io_uring: hold 'ctx' reference around task_work queue + execute
[linux-2.6-microblaze.git] / fs / io_uring.c
index 493e504..99582cf 100644 (file)
@@ -78,6 +78,7 @@
 #include <linux/fs_struct.h>
 #include <linux/splice.h>
 #include <linux/task_work.h>
+#include <linux/pagemap.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/io_uring.h>
@@ -226,7 +227,7 @@ struct io_ring_ctx {
        struct {
                unsigned int            flags;
                unsigned int            compat: 1;
-               unsigned int            account_mem: 1;
+               unsigned int            limit_mem: 1;
                unsigned int            cq_overflow_flushed: 1;
                unsigned int            drain_next: 1;
                unsigned int            eventfd_async: 1;
@@ -319,12 +320,12 @@ struct io_ring_ctx {
                spinlock_t              completion_lock;
 
                /*
-                * ->poll_list is protected by the ctx->uring_lock for
+                * ->iopoll_list is protected by the ctx->uring_lock for
                 * io_uring instances that don't use IORING_SETUP_SQPOLL.
                 * For SQPOLL, only the single threaded io_sq_thread() will
                 * manipulate the list, hence no extra locking is needed there.
                 */
-               struct list_head        poll_list;
+               struct list_head        iopoll_list;
                struct hlist_head       *cancel_hash;
                unsigned                cancel_hash_bits;
                bool                    poll_multi_file;
@@ -395,6 +396,7 @@ struct io_timeout {
        int                             flags;
        u32                             off;
        u32                             target_seq;
+       struct list_head                list;
 };
 
 struct io_rw {
@@ -413,7 +415,7 @@ struct io_connect {
 struct io_sr_msg {
        struct file                     *file;
        union {
-               struct user_msghdr __user *msg;
+               struct user_msghdr __user *umsg;
                void __user             *buf;
        };
        int                             msg_flags;
@@ -486,6 +488,12 @@ struct io_statx {
        struct statx __user             *buffer;
 };
 
+struct io_completion {
+       struct file                     *file;
+       struct list_head                list;
+       int                             cflags;
+};
+
 struct io_async_connect {
        struct sockaddr_storage         address;
 };
@@ -503,6 +511,7 @@ struct io_async_rw {
        struct iovec                    *iov;
        ssize_t                         nr_segs;
        ssize_t                         size;
+       struct wait_page_queue          wpq;
 };
 
 struct io_async_ctx {
@@ -523,23 +532,18 @@ enum {
        REQ_F_BUFFER_SELECT_BIT = IOSQE_BUFFER_SELECT_BIT,
 
        REQ_F_LINK_HEAD_BIT,
-       REQ_F_LINK_NEXT_BIT,
        REQ_F_FAIL_LINK_BIT,
        REQ_F_INFLIGHT_BIT,
        REQ_F_CUR_POS_BIT,
        REQ_F_NOWAIT_BIT,
        REQ_F_LINK_TIMEOUT_BIT,
-       REQ_F_TIMEOUT_BIT,
        REQ_F_ISREG_BIT,
-       REQ_F_MUST_PUNT_BIT,
-       REQ_F_TIMEOUT_NOSEQ_BIT,
        REQ_F_COMP_LOCKED_BIT,
        REQ_F_NEED_CLEANUP_BIT,
        REQ_F_OVERFLOW_BIT,
        REQ_F_POLLED_BIT,
        REQ_F_BUFFER_SELECTED_BIT,
        REQ_F_NO_FILE_TABLE_BIT,
-       REQ_F_QUEUE_TIMEOUT_BIT,
        REQ_F_WORK_INITIALIZED_BIT,
        REQ_F_TASK_PINNED_BIT,
 
@@ -563,8 +567,6 @@ enum {
 
        /* head of a link */
        REQ_F_LINK_HEAD         = BIT(REQ_F_LINK_HEAD_BIT),
-       /* already grabbed next link */
-       REQ_F_LINK_NEXT         = BIT(REQ_F_LINK_NEXT_BIT),
        /* fail rest of links */
        REQ_F_FAIL_LINK         = BIT(REQ_F_FAIL_LINK_BIT),
        /* on inflight list */
@@ -575,14 +577,8 @@ enum {
        REQ_F_NOWAIT            = BIT(REQ_F_NOWAIT_BIT),
        /* has linked timeout */
        REQ_F_LINK_TIMEOUT      = BIT(REQ_F_LINK_TIMEOUT_BIT),
-       /* timeout request */
-       REQ_F_TIMEOUT           = BIT(REQ_F_TIMEOUT_BIT),
        /* regular file */
        REQ_F_ISREG             = BIT(REQ_F_ISREG_BIT),
-       /* must be punted even for NONBLOCK */
-       REQ_F_MUST_PUNT         = BIT(REQ_F_MUST_PUNT_BIT),
-       /* no timeout sequence */
-       REQ_F_TIMEOUT_NOSEQ     = BIT(REQ_F_TIMEOUT_NOSEQ_BIT),
        /* completion under lock */
        REQ_F_COMP_LOCKED       = BIT(REQ_F_COMP_LOCKED_BIT),
        /* needs cleanup */
@@ -595,8 +591,6 @@ enum {
        REQ_F_BUFFER_SELECTED   = BIT(REQ_F_BUFFER_SELECTED_BIT),
        /* doesn't need file table for this request */
        REQ_F_NO_FILE_TABLE     = BIT(REQ_F_NO_FILE_TABLE_BIT),
-       /* needs to queue linked timeout */
-       REQ_F_QUEUE_TIMEOUT     = BIT(REQ_F_QUEUE_TIMEOUT_BIT),
        /* io_wq_work is initialized */
        REQ_F_WORK_INITIALIZED  = BIT(REQ_F_WORK_INITIALIZED_BIT),
        /* req->task is refcounted */
@@ -606,7 +600,6 @@ enum {
 struct async_poll {
        struct io_poll_iocb     poll;
        struct io_poll_iocb     *double_poll;
-       struct io_wq_work       work;
 };
 
 /*
@@ -635,51 +628,54 @@ struct io_kiocb {
                struct io_splice        splice;
                struct io_provide_buf   pbuf;
                struct io_statx         statx;
+               /* use only after cleaning per-op data, see io_clean_op() */
+               struct io_completion    compl;
        };
 
        struct io_async_ctx             *io;
-       int                             cflags;
        u8                              opcode;
        /* polled IO has completed */
        u8                              iopoll_completed;
 
        u16                             buf_index;
+       u32                             result;
 
-       struct io_ring_ctx      *ctx;
-       struct list_head        list;
-       unsigned int            flags;
-       refcount_t              refs;
-       struct task_struct      *task;
-       unsigned long           fsize;
-       u64                     user_data;
-       u32                     result;
-       u32                     sequence;
-
-       struct list_head        link_list;
+       struct io_ring_ctx              *ctx;
+       unsigned int                    flags;
+       refcount_t                      refs;
+       struct task_struct              *task;
+       u64                             user_data;
 
-       struct list_head        inflight_entry;
+       struct list_head                link_list;
 
-       struct percpu_ref       *fixed_file_refs;
+       /*
+        * 1. used with ctx->iopoll_list with reads/writes
+        * 2. to track reqs with ->files (see io_op_def::file_table)
+        */
+       struct list_head                inflight_entry;
+
+       struct percpu_ref               *fixed_file_refs;
+       struct callback_head            task_work;
+       /* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */
+       struct hlist_node               hash_node;
+       struct async_poll               *apoll;
+       struct io_wq_work               work;
+};
 
-       union {
-               /*
-                * Only commands that never go async can use the below fields,
-                * obviously. Right now only IORING_OP_POLL_ADD uses them, and
-                * async armed poll handlers for regular commands. The latter
-                * restore the work, if needed.
-                */
-               struct {
-                       struct callback_head    task_work;
-                       struct hlist_node       hash_node;
-                       struct async_poll       *apoll;
-               };
-               struct io_wq_work       work;
-       };
+struct io_defer_entry {
+       struct list_head        list;
+       struct io_kiocb         *req;
+       u32                     seq;
 };
 
-#define IO_PLUG_THRESHOLD              2
 #define IO_IOPOLL_BATCH                        8
 
+struct io_comp_state {
+       unsigned int            nr;
+       struct list_head        list;
+       struct io_ring_ctx      *ctx;
+};
+
 struct io_submit_state {
        struct blk_plug         plug;
 
@@ -689,13 +685,17 @@ struct io_submit_state {
        void                    *reqs[IO_IOPOLL_BATCH];
        unsigned int            free_reqs;
 
+       /*
+        * Batch completion logic
+        */
+       struct io_comp_state    comp;
+
        /*
         * File reference cache
         */
        struct file             *file;
        unsigned int            fd;
        unsigned int            has_refs;
-       unsigned int            used_refs;
        unsigned int            ios_left;
 };
 
@@ -723,6 +723,7 @@ struct io_op_def {
        unsigned                pollout : 1;
        /* op supports buffer selection */
        unsigned                buffer_select : 1;
+       unsigned                needs_fsize : 1;
 };
 
 static const struct io_op_def io_op_defs[] = {
@@ -742,6 +743,7 @@ static const struct io_op_def io_op_defs[] = {
                .hash_reg_file          = 1,
                .unbound_nonreg_file    = 1,
                .pollout                = 1,
+               .needs_fsize            = 1,
        },
        [IORING_OP_FSYNC] = {
                .needs_file             = 1,
@@ -756,6 +758,7 @@ static const struct io_op_def io_op_defs[] = {
                .hash_reg_file          = 1,
                .unbound_nonreg_file    = 1,
                .pollout                = 1,
+               .needs_fsize            = 1,
        },
        [IORING_OP_POLL_ADD] = {
                .needs_file             = 1,
@@ -808,6 +811,7 @@ static const struct io_op_def io_op_defs[] = {
        },
        [IORING_OP_FALLOCATE] = {
                .needs_file             = 1,
+               .needs_fsize            = 1,
        },
        [IORING_OP_OPENAT] = {
                .file_table             = 1,
@@ -839,6 +843,7 @@ static const struct io_op_def io_op_defs[] = {
                .needs_file             = 1,
                .unbound_nonreg_file    = 1,
                .pollout                = 1,
+               .needs_fsize            = 1,
        },
        [IORING_OP_FADVISE] = {
                .needs_file             = 1,
@@ -881,22 +886,38 @@ static const struct io_op_def io_op_defs[] = {
        },
 };
 
-static void io_wq_submit_work(struct io_wq_work **workptr);
+enum io_mem_account {
+       ACCT_LOCKED,
+       ACCT_PINNED,
+};
+
+static void __io_complete_rw(struct io_kiocb *req, long res, long res2,
+                            struct io_comp_state *cs);
 static void io_cqring_fill_event(struct io_kiocb *req, long res);
 static void io_put_req(struct io_kiocb *req);
+static void io_double_put_req(struct io_kiocb *req);
 static void __io_double_put_req(struct io_kiocb *req);
 static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req);
+static void __io_queue_linked_timeout(struct io_kiocb *req);
 static void io_queue_linked_timeout(struct io_kiocb *req);
 static int __io_sqe_files_update(struct io_ring_ctx *ctx,
                                 struct io_uring_files_update *ip,
                                 unsigned nr_args);
-static int io_grab_files(struct io_kiocb *req);
-static void io_complete_rw_common(struct kiocb *kiocb, long res);
-static void io_cleanup_req(struct io_kiocb *req);
+static int io_prep_work_files(struct io_kiocb *req);
+static void __io_clean_op(struct io_kiocb *req);
 static int io_file_get(struct io_submit_state *state, struct io_kiocb *req,
                       int fd, struct file **out_file, bool fixed);
 static void __io_queue_sqe(struct io_kiocb *req,
-                          const struct io_uring_sqe *sqe);
+                          const struct io_uring_sqe *sqe,
+                          struct io_comp_state *cs);
+static void io_file_put_work(struct work_struct *work);
+
+static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
+                              struct iovec **iovec, struct iov_iter *iter,
+                              bool needs_lock);
+static int io_setup_async_rw(struct io_kiocb *req, ssize_t io_size,
+                            struct iovec *iovec, struct iovec *fast_iov,
+                            struct iov_iter *iter);
 
 static struct kmem_cache *req_cachep;
 
@@ -923,6 +944,12 @@ static void io_get_req_task(struct io_kiocb *req)
        req->flags |= REQ_F_TASK_PINNED;
 }
 
+static inline void io_clean_op(struct io_kiocb *req)
+{
+       if (req->flags & (REQ_F_NEED_CLEANUP | REQ_F_BUFFER_SELECTED))
+               __io_clean_op(req);
+}
+
 /* not idempotent -- it doesn't clear REQ_F_TASK_PINNED */
 static void __io_put_req_task(struct io_kiocb *req)
 {
@@ -930,7 +957,41 @@ static void __io_put_req_task(struct io_kiocb *req)
                put_task_struct(req->task);
 }
 
-static void io_file_put_work(struct work_struct *work);
+static void io_sq_thread_drop_mm(void)
+{
+       struct mm_struct *mm = current->mm;
+
+       if (mm) {
+               kthread_unuse_mm(mm);
+               mmput(mm);
+       }
+}
+
+static int __io_sq_thread_acquire_mm(struct io_ring_ctx *ctx)
+{
+       if (!current->mm) {
+               if (unlikely(!(ctx->flags & IORING_SETUP_SQPOLL) ||
+                            !mmget_not_zero(ctx->sqo_mm)))
+                       return -EFAULT;
+               kthread_use_mm(ctx->sqo_mm);
+       }
+
+       return 0;
+}
+
+static int io_sq_thread_acquire_mm(struct io_ring_ctx *ctx,
+                                  struct io_kiocb *req)
+{
+       if (!io_op_defs[req->opcode].needs_mm)
+               return 0;
+       return __io_sq_thread_acquire_mm(ctx);
+}
+
+static inline void req_set_fail_links(struct io_kiocb *req)
+{
+       if ((req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) == REQ_F_LINK)
+               req->flags |= REQ_F_FAIL_LINK;
+}
 
 /*
  * Note: must call io_req_init_async() for the first time you
@@ -957,6 +1018,11 @@ static void io_ring_ctx_ref_free(struct percpu_ref *ref)
        complete(&ctx->ref_comp);
 }
 
+static inline bool io_is_timeout_noseq(struct io_kiocb *req)
+{
+       return !req->timeout.off;
+}
+
 static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
 {
        struct io_ring_ctx *ctx;
@@ -1000,7 +1066,7 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
        mutex_init(&ctx->uring_lock);
        init_waitqueue_head(&ctx->wait);
        spin_lock_init(&ctx->completion_lock);
-       INIT_LIST_HEAD(&ctx->poll_list);
+       INIT_LIST_HEAD(&ctx->iopoll_list);
        INIT_LIST_HEAD(&ctx->defer_list);
        INIT_LIST_HEAD(&ctx->timeout_list);
        init_waitqueue_head(&ctx->inflight_wait);
@@ -1017,18 +1083,14 @@ err:
        return NULL;
 }
 
-static inline bool __req_need_defer(struct io_kiocb *req)
+static bool req_need_defer(struct io_kiocb *req, u32 seq)
 {
-       struct io_ring_ctx *ctx = req->ctx;
+       if (unlikely(req->flags & REQ_F_IO_DRAIN)) {
+               struct io_ring_ctx *ctx = req->ctx;
 
-       return req->sequence != ctx->cached_cq_tail
+               return seq != ctx->cached_cq_tail
                                + atomic_read(&ctx->cached_cq_overflow);
-}
-
-static inline bool req_need_defer(struct io_kiocb *req)
-{
-       if (unlikely(req->flags & REQ_F_IO_DRAIN))
-               return __req_need_defer(req);
+       }
 
        return false;
 }
@@ -1046,31 +1108,16 @@ static void __io_commit_cqring(struct io_ring_ctx *ctx)
        }
 }
 
-static inline void io_req_work_grab_env(struct io_kiocb *req,
-                                       const struct io_op_def *def)
-{
-       if (!req->work.mm && def->needs_mm) {
-               mmgrab(current->mm);
-               req->work.mm = current->mm;
-       }
-       if (!req->work.creds)
-               req->work.creds = get_current_cred();
-       if (!req->work.fs && def->needs_fs) {
-               spin_lock(&current->fs->lock);
-               if (!current->fs->in_exec) {
-                       req->work.fs = current->fs;
-                       req->work.fs->users++;
-               } else {
-                       req->work.flags |= IO_WQ_WORK_CANCEL;
-               }
-               spin_unlock(&current->fs->lock);
-       }
-}
-
-static inline void io_req_work_drop_env(struct io_kiocb *req)
+/*
+ * Returns true if we need to defer file table putting. This can only happen
+ * from the error path with REQ_F_COMP_LOCKED set.
+ */
+static bool io_req_clean_work(struct io_kiocb *req)
 {
        if (!(req->flags & REQ_F_WORK_INITIALIZED))
-               return;
+               return false;
+
+       req->flags &= ~REQ_F_WORK_INITIALIZED;
 
        if (req->work.mm) {
                mmdrop(req->work.mm);
@@ -1083,17 +1130,22 @@ static inline void io_req_work_drop_env(struct io_kiocb *req)
        if (req->work.fs) {
                struct fs_struct *fs = req->work.fs;
 
+               if (req->flags & REQ_F_COMP_LOCKED)
+                       return true;
+
                spin_lock(&req->work.fs->lock);
                if (--fs->users)
                        fs = NULL;
                spin_unlock(&req->work.fs->lock);
                if (fs)
                        free_fs_struct(fs);
+               req->work.fs = NULL;
        }
+
+       return false;
 }
 
-static inline void io_prep_async_work(struct io_kiocb *req,
-                                     struct io_kiocb **link)
+static void io_prep_async_work(struct io_kiocb *req)
 {
        const struct io_op_def *def = &io_op_defs[req->opcode];
 
@@ -1106,22 +1158,56 @@ static inline void io_prep_async_work(struct io_kiocb *req,
                if (def->unbound_nonreg_file)
                        req->work.flags |= IO_WQ_WORK_UNBOUND;
        }
+       if (!req->work.mm && def->needs_mm) {
+               mmgrab(current->mm);
+               req->work.mm = current->mm;
+       }
+       if (!req->work.creds)
+               req->work.creds = get_current_cred();
+       if (!req->work.fs && def->needs_fs) {
+               spin_lock(&current->fs->lock);
+               if (!current->fs->in_exec) {
+                       req->work.fs = current->fs;
+                       req->work.fs->users++;
+               } else {
+                       req->work.flags |= IO_WQ_WORK_CANCEL;
+               }
+               spin_unlock(&current->fs->lock);
+       }
+       if (def->needs_fsize)
+               req->work.fsize = rlimit(RLIMIT_FSIZE);
+       else
+               req->work.fsize = RLIM_INFINITY;
+}
 
-       io_req_work_grab_env(req, def);
+static void io_prep_async_link(struct io_kiocb *req)
+{
+       struct io_kiocb *cur;
 
-       *link = io_prep_linked_timeout(req);
+       io_prep_async_work(req);
+       if (req->flags & REQ_F_LINK_HEAD)
+               list_for_each_entry(cur, &req->link_list, link_list)
+                       io_prep_async_work(cur);
 }
 
-static inline void io_queue_async_work(struct io_kiocb *req)
+static struct io_kiocb *__io_queue_async_work(struct io_kiocb *req)
 {
        struct io_ring_ctx *ctx = req->ctx;
-       struct io_kiocb *link;
-
-       io_prep_async_work(req, &link);
+       struct io_kiocb *link = io_prep_linked_timeout(req);
 
        trace_io_uring_queue_async_work(ctx, io_wq_is_hashed(&req->work), req,
                                        &req->work, req->flags);
        io_wq_enqueue(ctx->io_wq, &req->work);
+       return link;
+}
+
+static void io_queue_async_work(struct io_kiocb *req)
+{
+       struct io_kiocb *link;
+
+       /* init ->work of the whole link before punting */
+       io_prep_async_link(req);
+       link = __io_queue_async_work(req);
 
        if (link)
                io_queue_linked_timeout(link);
@@ -1133,8 +1219,9 @@ static void io_kill_timeout(struct io_kiocb *req)
 
        ret = hrtimer_try_to_cancel(&req->io->timeout.timer);
        if (ret != -1) {
-               atomic_inc(&req->ctx->cq_timeouts);
-               list_del_init(&req->list);
+               atomic_set(&req->ctx->cq_timeouts,
+                       atomic_read(&req->ctx->cq_timeouts) + 1);
+               list_del_init(&req->timeout.list);
                req->flags |= REQ_F_COMP_LOCKED;
                io_cqring_fill_event(req, 0);
                io_put_req(req);
@@ -1146,7 +1233,7 @@ static void io_kill_timeouts(struct io_ring_ctx *ctx)
        struct io_kiocb *req, *tmp;
 
        spin_lock_irq(&ctx->completion_lock);
-       list_for_each_entry_safe(req, tmp, &ctx->timeout_list, list)
+       list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list)
                io_kill_timeout(req);
        spin_unlock_irq(&ctx->completion_lock);
 }
@@ -1154,13 +1241,22 @@ static void io_kill_timeouts(struct io_ring_ctx *ctx)
 static void __io_queue_deferred(struct io_ring_ctx *ctx)
 {
        do {
-               struct io_kiocb *req = list_first_entry(&ctx->defer_list,
-                                                       struct io_kiocb, list);
+               struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
+                                               struct io_defer_entry, list);
+               struct io_kiocb *link;
 
-               if (req_need_defer(req))
+               if (req_need_defer(de->req, de->seq))
                        break;
-               list_del_init(&req->list);
-               io_queue_async_work(req);
+               list_del_init(&de->list);
+               /* punt-init is done before queueing for defer */
+               link = __io_queue_async_work(de->req);
+               if (link) {
+                       __io_queue_linked_timeout(link);
+                       /* drop submission reference */
+                       link->flags |= REQ_F_COMP_LOCKED;
+                       io_put_req(link);
+               }
+               kfree(de);
        } while (!list_empty(&ctx->defer_list));
 }
 
@@ -1168,15 +1264,15 @@ static void io_flush_timeouts(struct io_ring_ctx *ctx)
 {
        while (!list_empty(&ctx->timeout_list)) {
                struct io_kiocb *req = list_first_entry(&ctx->timeout_list,
-                                                       struct io_kiocb, list);
+                                               struct io_kiocb, timeout.list);
 
-               if (req->flags & REQ_F_TIMEOUT_NOSEQ)
+               if (io_is_timeout_noseq(req))
                        break;
                if (req->timeout.target_seq != ctx->cached_cq_tail
                                        - atomic_read(&ctx->cq_timeouts))
                        break;
 
-               list_del_init(&req->list);
+               list_del_init(&req->timeout.list);
                io_kill_timeout(req);
        }
 }
@@ -1229,6 +1325,15 @@ static void io_cqring_ev_posted(struct io_ring_ctx *ctx)
                eventfd_signal(ctx->cq_ev_fd, 1);
 }
 
+static void io_cqring_mark_overflow(struct io_ring_ctx *ctx)
+{
+       if (list_empty(&ctx->cq_overflow_list)) {
+               clear_bit(0, &ctx->sq_check_overflow);
+               clear_bit(0, &ctx->cq_check_overflow);
+               ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW;
+       }
+}
+
 /* Returns true if there are no backlogged entries after the flush */
 static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
 {
@@ -1259,13 +1364,13 @@ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
                        break;
 
                req = list_first_entry(&ctx->cq_overflow_list, struct io_kiocb,
-                                               list);
-               list_move(&req->list, &list);
+                                               compl.list);
+               list_move(&req->compl.list, &list);
                req->flags &= ~REQ_F_OVERFLOW;
                if (cqe) {
                        WRITE_ONCE(cqe->user_data, req->user_data);
                        WRITE_ONCE(cqe->res, req->result);
-                       WRITE_ONCE(cqe->flags, req->cflags);
+                       WRITE_ONCE(cqe->flags, req->compl.cflags);
                } else {
                        WRITE_ONCE(ctx->rings->cq_overflow,
                                atomic_inc_return(&ctx->cached_cq_overflow));
@@ -1273,17 +1378,14 @@ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
        }
 
        io_commit_cqring(ctx);
-       if (cqe) {
-               clear_bit(0, &ctx->sq_check_overflow);
-               clear_bit(0, &ctx->cq_check_overflow);
-               ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW;
-       }
+       io_cqring_mark_overflow(ctx);
+
        spin_unlock_irqrestore(&ctx->completion_lock, flags);
        io_cqring_ev_posted(ctx);
 
        while (!list_empty(&list)) {
-               req = list_first_entry(&list, struct io_kiocb, list);
-               list_del(&req->list);
+               req = list_first_entry(&list, struct io_kiocb, compl.list);
+               list_del(&req->compl.list);
                io_put_req(req);
        }
 
@@ -1316,11 +1418,12 @@ static void __io_cqring_fill_event(struct io_kiocb *req, long res, long cflags)
                        set_bit(0, &ctx->cq_check_overflow);
                        ctx->rings->sq_flags |= IORING_SQ_CQ_OVERFLOW;
                }
+               io_clean_op(req);
                req->flags |= REQ_F_OVERFLOW;
-               refcount_inc(&req->refs);
                req->result = res;
-               req->cflags = cflags;
-               list_add_tail(&req->list, &ctx->cq_overflow_list);
+               req->compl.cflags = cflags;
+               refcount_inc(&req->refs);
+               list_add_tail(&req->compl.list, &ctx->cq_overflow_list);
        }
 }
 
@@ -1329,7 +1432,7 @@ static void io_cqring_fill_event(struct io_kiocb *req, long res)
        __io_cqring_fill_event(req, res, 0);
 }
 
-static void __io_cqring_add_event(struct io_kiocb *req, long res, long cflags)
+static void io_cqring_add_event(struct io_kiocb *req, long res, long cflags)
 {
        struct io_ring_ctx *ctx = req->ctx;
        unsigned long flags;
@@ -1342,9 +1445,52 @@ static void __io_cqring_add_event(struct io_kiocb *req, long res, long cflags)
        io_cqring_ev_posted(ctx);
 }
 
-static void io_cqring_add_event(struct io_kiocb *req, long res)
+static void io_submit_flush_completions(struct io_comp_state *cs)
+{
+       struct io_ring_ctx *ctx = cs->ctx;
+
+       spin_lock_irq(&ctx->completion_lock);
+       while (!list_empty(&cs->list)) {
+               struct io_kiocb *req;
+
+               req = list_first_entry(&cs->list, struct io_kiocb, compl.list);
+               list_del(&req->compl.list);
+               __io_cqring_fill_event(req, req->result, req->compl.cflags);
+               if (!(req->flags & REQ_F_LINK_HEAD)) {
+                       req->flags |= REQ_F_COMP_LOCKED;
+                       io_put_req(req);
+               } else {
+                       spin_unlock_irq(&ctx->completion_lock);
+                       io_put_req(req);
+                       spin_lock_irq(&ctx->completion_lock);
+               }
+       }
+       io_commit_cqring(ctx);
+       spin_unlock_irq(&ctx->completion_lock);
+
+       io_cqring_ev_posted(ctx);
+       cs->nr = 0;
+}
+
+static void __io_req_complete(struct io_kiocb *req, long res, unsigned cflags,
+                             struct io_comp_state *cs)
+{
+       if (!cs) {
+               io_cqring_add_event(req, res, cflags);
+               io_put_req(req);
+       } else {
+               io_clean_op(req);
+               req->result = res;
+               req->compl.cflags = cflags;
+               list_add_tail(&req->compl.list, &cs->list);
+               if (++cs->nr >= 32)
+                       io_submit_flush_completions(cs);
+       }
+}
+
+static void io_req_complete(struct io_kiocb *req, long res)
 {
-       __io_cqring_add_event(req, res, 0);
+       __io_req_complete(req, res, 0, NULL);
 }
 
 static inline bool io_is_fallback_req(struct io_kiocb *req)
@@ -1370,11 +1516,7 @@ static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx,
        gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
        struct io_kiocb *req;
 
-       if (!state) {
-               req = kmem_cache_alloc(req_cachep, gfp);
-               if (unlikely(!req))
-                       goto fallback;
-       } else if (!state->free_reqs) {
+       if (!state->free_reqs) {
                size_t sz;
                int ret;
 
@@ -1412,21 +1554,14 @@ static inline void io_put_file(struct io_kiocb *req, struct file *file,
                fput(file);
 }
 
-static void __io_req_aux_free(struct io_kiocb *req)
+static bool io_dismantle_req(struct io_kiocb *req)
 {
-       if (req->flags & REQ_F_NEED_CLEANUP)
-               io_cleanup_req(req);
+       io_clean_op(req);
 
-       kfree(req->io);
+       if (req->io)
+               kfree(req->io);
        if (req->file)
                io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE));
-       __io_put_req_task(req);
-       io_req_work_drop_env(req);
-}
-
-static void __io_free_req(struct io_kiocb *req)
-{
-       __io_req_aux_free(req);
 
        if (req->flags & REQ_F_INFLIGHT) {
                struct io_ring_ctx *ctx = req->ctx;
@@ -1439,56 +1574,52 @@ static void __io_free_req(struct io_kiocb *req)
                spin_unlock_irqrestore(&ctx->inflight_lock, flags);
        }
 
-       percpu_ref_put(&req->ctx->refs);
+       return io_req_clean_work(req);
+}
+
+static void __io_free_req_finish(struct io_kiocb *req)
+{
+       struct io_ring_ctx *ctx = req->ctx;
+
+       __io_put_req_task(req);
        if (likely(!io_is_fallback_req(req)))
                kmem_cache_free(req_cachep, req);
        else
-               clear_bit_unlock(0, (unsigned long *) &req->ctx->fallback_req);
+               clear_bit_unlock(0, (unsigned long *) &ctx->fallback_req);
+       percpu_ref_put(&ctx->refs);
 }
 
-struct req_batch {
-       void *reqs[IO_IOPOLL_BATCH];
-       int to_free;
-       int need_iter;
-};
-
-static void io_free_req_many(struct io_ring_ctx *ctx, struct req_batch *rb)
+static void io_req_task_file_table_put(struct callback_head *cb)
 {
-       if (!rb->to_free)
-               return;
-       if (rb->need_iter) {
-               int i, inflight = 0;
-               unsigned long flags;
+       struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
+       struct fs_struct *fs = req->work.fs;
 
-               for (i = 0; i < rb->to_free; i++) {
-                       struct io_kiocb *req = rb->reqs[i];
+       spin_lock(&req->work.fs->lock);
+       if (--fs->users)
+               fs = NULL;
+       spin_unlock(&req->work.fs->lock);
+       if (fs)
+               free_fs_struct(fs);
+       req->work.fs = NULL;
+       __io_free_req_finish(req);
+}
 
-                       if (req->flags & REQ_F_INFLIGHT)
-                               inflight++;
-                       __io_req_aux_free(req);
-               }
-               if (!inflight)
-                       goto do_free;
+static void __io_free_req(struct io_kiocb *req)
+{
+       if (!io_dismantle_req(req)) {
+               __io_free_req_finish(req);
+       } else {
+               int ret;
 
-               spin_lock_irqsave(&ctx->inflight_lock, flags);
-               for (i = 0; i < rb->to_free; i++) {
-                       struct io_kiocb *req = rb->reqs[i];
+               init_task_work(&req->task_work, io_req_task_file_table_put);
+               ret = task_work_add(req->task, &req->task_work, TWA_RESUME);
+               if (unlikely(ret)) {
+                       struct task_struct *tsk;
 
-                       if (req->flags & REQ_F_INFLIGHT) {
-                               list_del(&req->inflight_entry);
-                               if (!--inflight)
-                                       break;
-                       }
+                       tsk = io_wq_get_task(req->ctx->io_wq);
+                       task_work_add(tsk, &req->task_work, 0);
                }
-               spin_unlock_irqrestore(&ctx->inflight_lock, flags);
-
-               if (waitqueue_active(&ctx->inflight_wait))
-                       wake_up(&ctx->inflight_wait);
        }
-do_free:
-       kmem_cache_free_bulk(req_cachep, rb->to_free, rb->reqs);
-       percpu_ref_put_many(&ctx->refs, rb->to_free);
-       rb->to_free = rb->need_iter = 0;
 }
 
 static bool io_link_cancel_timeout(struct io_kiocb *req)
@@ -1508,53 +1639,68 @@ static bool io_link_cancel_timeout(struct io_kiocb *req)
        return false;
 }
 
-static void io_req_link_next(struct io_kiocb *req, struct io_kiocb **nxtptr)
+static bool __io_kill_linked_timeout(struct io_kiocb *req)
+{
+       struct io_kiocb *link;
+       bool wake_ev;
+
+       if (list_empty(&req->link_list))
+               return false;
+       link = list_first_entry(&req->link_list, struct io_kiocb, link_list);
+       if (link->opcode != IORING_OP_LINK_TIMEOUT)
+               return false;
+
+       list_del_init(&link->link_list);
+       link->flags |= REQ_F_COMP_LOCKED;
+       wake_ev = io_link_cancel_timeout(link);
+       req->flags &= ~REQ_F_LINK_TIMEOUT;
+       return wake_ev;
+}
+
+static void io_kill_linked_timeout(struct io_kiocb *req)
 {
        struct io_ring_ctx *ctx = req->ctx;
-       bool wake_ev = false;
+       bool wake_ev;
 
-       /* Already got next link */
-       if (req->flags & REQ_F_LINK_NEXT)
-               return;
+       if (!(req->flags & REQ_F_COMP_LOCKED)) {
+               unsigned long flags;
+
+               spin_lock_irqsave(&ctx->completion_lock, flags);
+               wake_ev = __io_kill_linked_timeout(req);
+               spin_unlock_irqrestore(&ctx->completion_lock, flags);
+       } else {
+               wake_ev = __io_kill_linked_timeout(req);
+       }
+
+       if (wake_ev)
+               io_cqring_ev_posted(ctx);
+}
+
+static struct io_kiocb *io_req_link_next(struct io_kiocb *req)
+{
+       struct io_kiocb *nxt;
 
        /*
         * The list should never be empty when we are called here. But could
         * potentially happen if the chain is messed up, check to be on the
         * safe side.
         */
-       while (!list_empty(&req->link_list)) {
-               struct io_kiocb *nxt = list_first_entry(&req->link_list,
-                                               struct io_kiocb, link_list);
-
-               if (unlikely((req->flags & REQ_F_LINK_TIMEOUT) &&
-                            (nxt->flags & REQ_F_TIMEOUT))) {
-                       list_del_init(&nxt->link_list);
-                       wake_ev |= io_link_cancel_timeout(nxt);
-                       req->flags &= ~REQ_F_LINK_TIMEOUT;
-                       continue;
-               }
-
-               list_del_init(&req->link_list);
-               if (!list_empty(&nxt->link_list))
-                       nxt->flags |= REQ_F_LINK_HEAD;
-               *nxtptr = nxt;
-               break;
-       }
+       if (unlikely(list_empty(&req->link_list)))
+               return NULL;
 
-       req->flags |= REQ_F_LINK_NEXT;
-       if (wake_ev)
-               io_cqring_ev_posted(ctx);
+       nxt = list_first_entry(&req->link_list, struct io_kiocb, link_list);
+       list_del_init(&req->link_list);
+       if (!list_empty(&nxt->link_list))
+               nxt->flags |= REQ_F_LINK_HEAD;
+       return nxt;
 }
 
 /*
  * Called if REQ_F_LINK_HEAD is set, and we fail the head request
  */
-static void io_fail_links(struct io_kiocb *req)
+static void __io_fail_links(struct io_kiocb *req)
 {
        struct io_ring_ctx *ctx = req->ctx;
-       unsigned long flags;
-
-       spin_lock_irqsave(&ctx->completion_lock, flags);
 
        while (!list_empty(&req->link_list)) {
                struct io_kiocb *link = list_first_entry(&req->link_list,
@@ -1563,88 +1709,229 @@ static void io_fail_links(struct io_kiocb *req)
                list_del_init(&link->link_list);
                trace_io_uring_fail_link(req, link);
 
-               if ((req->flags & REQ_F_LINK_TIMEOUT) &&
-                   link->opcode == IORING_OP_LINK_TIMEOUT) {
-                       io_link_cancel_timeout(link);
-               } else {
-                       io_cqring_fill_event(link, -ECANCELED);
-                       __io_double_put_req(link);
-               }
+               io_cqring_fill_event(link, -ECANCELED);
+               link->flags |= REQ_F_COMP_LOCKED;
+               __io_double_put_req(link);
                req->flags &= ~REQ_F_LINK_TIMEOUT;
        }
 
        io_commit_cqring(ctx);
-       spin_unlock_irqrestore(&ctx->completion_lock, flags);
        io_cqring_ev_posted(ctx);
 }
 
-static void io_req_find_next(struct io_kiocb *req, struct io_kiocb **nxt)
+static void io_fail_links(struct io_kiocb *req)
 {
-       if (likely(!(req->flags & REQ_F_LINK_HEAD)))
-               return;
+       struct io_ring_ctx *ctx = req->ctx;
 
-       /*
+       if (!(req->flags & REQ_F_COMP_LOCKED)) {
+               unsigned long flags;
+
+               spin_lock_irqsave(&ctx->completion_lock, flags);
+               __io_fail_links(req);
+               spin_unlock_irqrestore(&ctx->completion_lock, flags);
+       } else {
+               __io_fail_links(req);
+       }
+
+       io_cqring_ev_posted(ctx);
+}
+
+static struct io_kiocb *__io_req_find_next(struct io_kiocb *req)
+{
+       req->flags &= ~REQ_F_LINK_HEAD;
+       if (req->flags & REQ_F_LINK_TIMEOUT)
+               io_kill_linked_timeout(req);
+
+       /*
         * If LINK is set, we have dependent requests in this chain. If we
         * didn't fail this request, queue the first one up, moving any other
         * dependencies to the next request. In case of failure, fail the rest
         * of the chain.
         */
-       if (req->flags & REQ_F_FAIL_LINK) {
-               io_fail_links(req);
-       } else if ((req->flags & (REQ_F_LINK_TIMEOUT | REQ_F_COMP_LOCKED)) ==
-                       REQ_F_LINK_TIMEOUT) {
-               struct io_ring_ctx *ctx = req->ctx;
-               unsigned long flags;
+       if (likely(!(req->flags & REQ_F_FAIL_LINK)))
+               return io_req_link_next(req);
+       io_fail_links(req);
+       return NULL;
+}
 
-               /*
-                * If this is a timeout link, we could be racing with the
-                * timeout timer. Grab the completion lock for this case to
-                * protect against that.
-                */
-               spin_lock_irqsave(&ctx->completion_lock, flags);
-               io_req_link_next(req, nxt);
-               spin_unlock_irqrestore(&ctx->completion_lock, flags);
+static struct io_kiocb *io_req_find_next(struct io_kiocb *req)
+{
+       if (likely(!(req->flags & REQ_F_LINK_HEAD)))
+               return NULL;
+       return __io_req_find_next(req);
+}
+
+static int io_req_task_work_add(struct io_kiocb *req, struct callback_head *cb)
+{
+       struct task_struct *tsk = req->task;
+       struct io_ring_ctx *ctx = req->ctx;
+       int ret, notify;
+
+       /*
+        * SQPOLL kernel thread doesn't need notification, just a wakeup. For
+        * all other cases, use TWA_SIGNAL unconditionally to ensure we're
+        * processing task_work. There's no reliable way to tell if TWA_RESUME
+        * will do the job.
+        */
+       notify = 0;
+       if (!(ctx->flags & IORING_SETUP_SQPOLL))
+               notify = TWA_SIGNAL;
+
+       ret = task_work_add(tsk, cb, notify);
+       if (!ret)
+               wake_up_process(tsk);
+
+       return ret;
+}
+
+static void __io_req_task_cancel(struct io_kiocb *req, int error)
+{
+       struct io_ring_ctx *ctx = req->ctx;
+
+       spin_lock_irq(&ctx->completion_lock);
+       io_cqring_fill_event(req, error);
+       io_commit_cqring(ctx);
+       spin_unlock_irq(&ctx->completion_lock);
+
+       io_cqring_ev_posted(ctx);
+       req_set_fail_links(req);
+       io_double_put_req(req);
+}
+
+static void io_req_task_cancel(struct callback_head *cb)
+{
+       struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
+
+       __io_req_task_cancel(req, -ECANCELED);
+}
+
+static void __io_req_task_submit(struct io_kiocb *req)
+{
+       struct io_ring_ctx *ctx = req->ctx;
+
+       if (!__io_sq_thread_acquire_mm(ctx)) {
+               mutex_lock(&ctx->uring_lock);
+               __io_queue_sqe(req, NULL, NULL);
+               mutex_unlock(&ctx->uring_lock);
        } else {
-               io_req_link_next(req, nxt);
+               __io_req_task_cancel(req, -EFAULT);
        }
 }
 
-static void io_free_req(struct io_kiocb *req)
+static void io_req_task_submit(struct callback_head *cb)
 {
-       struct io_kiocb *nxt = NULL;
+       struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
+       struct io_ring_ctx *ctx = req->ctx;
 
-       io_req_find_next(req, &nxt);
-       __io_free_req(req);
+       __io_req_task_submit(req);
+       percpu_ref_put(&ctx->refs);
+}
+
+static void io_req_task_queue(struct io_kiocb *req)
+{
+       int ret;
+
+       init_task_work(&req->task_work, io_req_task_submit);
+       percpu_ref_get(&req->ctx->refs);
+
+       ret = io_req_task_work_add(req, &req->task_work);
+       if (unlikely(ret)) {
+               struct task_struct *tsk;
+
+               init_task_work(&req->task_work, io_req_task_cancel);
+               tsk = io_wq_get_task(req->ctx->io_wq);
+               task_work_add(tsk, &req->task_work, 0);
+               wake_up_process(tsk);
+       }
+}
+
+static void io_queue_next(struct io_kiocb *req)
+{
+       struct io_kiocb *nxt = io_req_find_next(req);
 
        if (nxt)
-               io_queue_async_work(nxt);
+               io_req_task_queue(nxt);
 }
 
-static void io_wq_assign_next(struct io_wq_work **workptr, struct io_kiocb *nxt)
+static void io_free_req(struct io_kiocb *req)
 {
-       struct io_kiocb *link;
-       const struct io_op_def *def = &io_op_defs[nxt->opcode];
+       io_queue_next(req);
+       __io_free_req(req);
+}
 
-       if ((nxt->flags & REQ_F_ISREG) && def->hash_reg_file)
-               io_wq_hash_work(&nxt->work, file_inode(nxt->file));
+struct req_batch {
+       void *reqs[IO_IOPOLL_BATCH];
+       int to_free;
 
-       *workptr = &nxt->work;
-       link = io_prep_linked_timeout(nxt);
-       if (link)
-               nxt->flags |= REQ_F_QUEUE_TIMEOUT;
+       struct task_struct      *task;
+       int                     task_refs;
+};
+
+static inline void io_init_req_batch(struct req_batch *rb)
+{
+       rb->to_free = 0;
+       rb->task_refs = 0;
+       rb->task = NULL;
+}
+
+static void __io_req_free_batch_flush(struct io_ring_ctx *ctx,
+                                     struct req_batch *rb)
+{
+       kmem_cache_free_bulk(req_cachep, rb->to_free, rb->reqs);
+       percpu_ref_put_many(&ctx->refs, rb->to_free);
+       rb->to_free = 0;
+}
+
+static void io_req_free_batch_finish(struct io_ring_ctx *ctx,
+                                    struct req_batch *rb)
+{
+       if (rb->to_free)
+               __io_req_free_batch_flush(ctx, rb);
+       if (rb->task) {
+               put_task_struct_many(rb->task, rb->task_refs);
+               rb->task = NULL;
+       }
+}
+
+static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req)
+{
+       if (unlikely(io_is_fallback_req(req))) {
+               io_free_req(req);
+               return;
+       }
+       if (req->flags & REQ_F_LINK_HEAD)
+               io_queue_next(req);
+
+       if (req->flags & REQ_F_TASK_PINNED) {
+               if (req->task != rb->task) {
+                       if (rb->task)
+                               put_task_struct_many(rb->task, rb->task_refs);
+                       rb->task = req->task;
+                       rb->task_refs = 0;
+               }
+               rb->task_refs++;
+               req->flags &= ~REQ_F_TASK_PINNED;
+       }
+
+       WARN_ON_ONCE(io_dismantle_req(req));
+       rb->reqs[rb->to_free++] = req;
+       if (unlikely(rb->to_free == ARRAY_SIZE(rb->reqs)))
+               __io_req_free_batch_flush(req->ctx, rb);
 }
 
 /*
  * Drop reference to request, return next in chain (if there is one) if this
  * was the last reference to this request.
  */
-__attribute__((nonnull))
-static void io_put_req_find_next(struct io_kiocb *req, struct io_kiocb **nxtptr)
+static struct io_kiocb *io_put_req_find_next(struct io_kiocb *req)
 {
+       struct io_kiocb *nxt = NULL;
+
        if (refcount_dec_and_test(&req->refs)) {
-               io_req_find_next(req, nxtptr);
+               nxt = io_req_find_next(req);
                __io_free_req(req);
        }
+       return nxt;
 }
 
 static void io_put_req(struct io_kiocb *req)
@@ -1653,24 +1940,20 @@ static void io_put_req(struct io_kiocb *req)
                io_free_req(req);
 }
 
-static void io_steal_work(struct io_kiocb *req,
-                         struct io_wq_work **workptr)
+static struct io_wq_work *io_steal_work(struct io_kiocb *req)
 {
+       struct io_kiocb *nxt;
+
        /*
-        * It's in an io-wq worker, so there always should be at least
-        * one reference, which will be dropped in io_put_work() just
-        * after the current handler returns.
-        *
-        * It also means, that if the counter dropped to 1, then there is
-        * no asynchronous users left, so it's safe to steal the next work.
+        * A ref is owned by io-wq in which context we're. So, if that's the
+        * last one, it's safe to steal next work. False negatives are Ok,
+        * it just will be re-punted async in io_put_work()
         */
-       if (refcount_read(&req->refs) == 1) {
-               struct io_kiocb *nxt = NULL;
+       if (refcount_read(&req->refs) != 1)
+               return NULL;
 
-               io_req_find_next(req, &nxt);
-               if (nxt)
-                       io_wq_assign_next(workptr, nxt);
-       }
+       nxt = io_req_find_next(req);
+       return nxt ? &nxt->work : NULL;
 }
 
 /*
@@ -1720,31 +2003,34 @@ static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
        return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
 }
 
-static inline bool io_req_multi_free(struct req_batch *rb, struct io_kiocb *req)
+static unsigned int io_put_kbuf(struct io_kiocb *req, struct io_buffer *kbuf)
 {
-       if ((req->flags & REQ_F_LINK_HEAD) || io_is_fallback_req(req))
-               return false;
+       unsigned int cflags;
 
-       if (req->file || req->io)
-               rb->need_iter++;
-
-       rb->reqs[rb->to_free++] = req;
-       if (unlikely(rb->to_free == ARRAY_SIZE(rb->reqs)))
-               io_free_req_many(req->ctx, rb);
-       return true;
+       cflags = kbuf->bid << IORING_CQE_BUFFER_SHIFT;
+       cflags |= IORING_CQE_F_BUFFER;
+       req->flags &= ~REQ_F_BUFFER_SELECTED;
+       kfree(kbuf);
+       return cflags;
 }
 
-static int io_put_kbuf(struct io_kiocb *req)
+static inline unsigned int io_put_rw_kbuf(struct io_kiocb *req)
 {
        struct io_buffer *kbuf;
-       int cflags;
 
        kbuf = (struct io_buffer *) (unsigned long) req->rw.addr;
-       cflags = kbuf->bid << IORING_CQE_BUFFER_SHIFT;
-       cflags |= IORING_CQE_F_BUFFER;
-       req->rw.addr = 0;
-       kfree(kbuf);
-       return cflags;
+       return io_put_kbuf(req, kbuf);
+}
+
+static inline bool io_run_task_work(void)
+{
+       if (current->task_works) {
+               __set_current_state(TASK_RUNNING);
+               task_work_run();
+               return true;
+       }
+
+       return false;
 }
 
 static void io_iopoll_queue(struct list_head *again)
@@ -1752,18 +2038,9 @@ static void io_iopoll_queue(struct list_head *again)
        struct io_kiocb *req;
 
        do {
-               req = list_first_entry(again, struct io_kiocb, list);
-               list_del(&req->list);
-
-               /* shouldn't happen unless io_uring is dying, cancel reqs */
-               if (unlikely(!current->mm)) {
-                       io_complete_rw_common(&req->rw.kiocb, -EAGAIN);
-                       io_put_req(req);
-                       continue;
-               }
-
-               refcount_inc(&req->refs);
-               io_queue_async_work(req);
+               req = list_first_entry(again, struct io_kiocb, inflight_entry);
+               list_del(&req->inflight_entry);
+               __io_complete_rw(req, -EAGAIN, 0, NULL);
        } while (!list_empty(again));
 }
 
@@ -1780,33 +2057,32 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
        /* order with ->result store in io_complete_rw_iopoll() */
        smp_rmb();
 
-       rb.to_free = rb.need_iter = 0;
+       io_init_req_batch(&rb);
        while (!list_empty(done)) {
                int cflags = 0;
 
-               req = list_first_entry(done, struct io_kiocb, list);
+               req = list_first_entry(done, struct io_kiocb, inflight_entry);
                if (READ_ONCE(req->result) == -EAGAIN) {
                        req->iopoll_completed = 0;
-                       list_move_tail(&req->list, &again);
+                       list_move_tail(&req->inflight_entry, &again);
                        continue;
                }
-               list_del(&req->list);
+               list_del(&req->inflight_entry);
 
                if (req->flags & REQ_F_BUFFER_SELECTED)
-                       cflags = io_put_kbuf(req);
+                       cflags = io_put_rw_kbuf(req);
 
                __io_cqring_fill_event(req, req->result, cflags);
                (*nr_events)++;
 
-               if (refcount_dec_and_test(&req->refs) &&
-                   !io_req_multi_free(&rb, req))
-                       io_free_req(req);
+               if (refcount_dec_and_test(&req->refs))
+                       io_req_free_batch(&rb, req);
        }
 
        io_commit_cqring(ctx);
        if (ctx->flags & IORING_SETUP_SQPOLL)
                io_cqring_ev_posted(ctx);
-       io_free_req_many(ctx, &rb);
+       io_req_free_batch_finish(ctx, &rb);
 
        if (!list_empty(&again))
                io_iopoll_queue(&again);
@@ -1827,7 +2103,7 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
        spin = !ctx->poll_multi_file && *nr_events < min;
 
        ret = 0;
-       list_for_each_entry_safe(req, tmp, &ctx->poll_list, list) {
+       list_for_each_entry_safe(req, tmp, &ctx->iopoll_list, inflight_entry) {
                struct kiocb *kiocb = &req->rw.kiocb;
 
                /*
@@ -1836,7 +2112,7 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
                 * and complete those lists first, if we have entries there.
                 */
                if (READ_ONCE(req->iopoll_completed)) {
-                       list_move_tail(&req->list, &done);
+                       list_move_tail(&req->inflight_entry, &done);
                        continue;
                }
                if (!list_empty(&done))
@@ -1846,6 +2122,10 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
                if (ret < 0)
                        break;
 
+               /* iopoll may have completed current req */
+               if (READ_ONCE(req->iopoll_completed))
+                       list_move_tail(&req->inflight_entry, &done);
+
                if (ret && spin)
                        spin = false;
                ret = 0;
@@ -1865,13 +2145,13 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
 static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events,
                                long min)
 {
-       while (!list_empty(&ctx->poll_list) && !need_resched()) {
+       while (!list_empty(&ctx->iopoll_list) && !need_resched()) {
                int ret;
 
                ret = io_do_iopoll(ctx, nr_events, min);
                if (ret < 0)
                        return ret;
-               if (!min || *nr_events >= min)
+               if (*nr_events >= min)
                        return 0;
        }
 
@@ -1882,29 +2162,37 @@ static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events,
  * We can't just wait for polled events to come to us, we have to actively
  * find and complete them.
  */
-static void io_iopoll_reap_events(struct io_ring_ctx *ctx)
+static void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)
 {
        if (!(ctx->flags & IORING_SETUP_IOPOLL))
                return;
 
        mutex_lock(&ctx->uring_lock);
-       while (!list_empty(&ctx->poll_list)) {
+       while (!list_empty(&ctx->iopoll_list)) {
                unsigned int nr_events = 0;
 
-               io_iopoll_getevents(ctx, &nr_events, 1);
+               io_do_iopoll(ctx, &nr_events, 0);
 
+               /* let it sleep and repeat later if can't complete a request */
+               if (nr_events == 0)
+                       break;
                /*
                 * Ensure we allow local-to-the-cpu processing to take place,
                 * in this case we need to ensure that we reap all events.
+                * Also let task_work, etc. to progress by releasing the mutex
                 */
-               cond_resched();
+               if (need_resched()) {
+                       mutex_unlock(&ctx->uring_lock);
+                       cond_resched();
+                       mutex_lock(&ctx->uring_lock);
+               }
        }
        mutex_unlock(&ctx->uring_lock);
 }
 
-static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
-                          long min)
+static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
 {
+       unsigned int nr_events = 0;
        int iters = 0, ret = 0;
 
        /*
@@ -1914,8 +2202,6 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
         */
        mutex_lock(&ctx->uring_lock);
        do {
-               int tmin = 0;
-
                /*
                 * Don't enter poll loop if we already have events pending.
                 * If we do, we can potentially be spinning for commands that
@@ -1936,17 +2222,15 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
                 */
                if (!(++iters & 7)) {
                        mutex_unlock(&ctx->uring_lock);
+                       io_run_task_work();
                        mutex_lock(&ctx->uring_lock);
                }
 
-               if (*nr_events < min)
-                       tmin = min - *nr_events;
-
-               ret = io_iopoll_getevents(ctx, nr_events, tmin);
+               ret = io_iopoll_getevents(ctx, &nr_events, min);
                if (ret <= 0)
                        break;
                ret = 0;
-       } while (min && !*nr_events && !need_resched());
+       } while (min && !nr_events && !need_resched());
 
        mutex_unlock(&ctx->uring_lock);
        return ret;
@@ -1966,13 +2250,8 @@ static void kiocb_end_write(struct io_kiocb *req)
        file_end_write(req->file);
 }
 
-static inline void req_set_fail_links(struct io_kiocb *req)
-{
-       if ((req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) == REQ_F_LINK)
-               req->flags |= REQ_F_FAIL_LINK;
-}
-
-static void io_complete_rw_common(struct kiocb *kiocb, long res)
+static void io_complete_rw_common(struct kiocb *kiocb, long res,
+                                 struct io_comp_state *cs)
 {
        struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
        int cflags = 0;
@@ -1983,16 +2262,100 @@ static void io_complete_rw_common(struct kiocb *kiocb, long res)
        if (res != req->result)
                req_set_fail_links(req);
        if (req->flags & REQ_F_BUFFER_SELECTED)
-               cflags = io_put_kbuf(req);
-       __io_cqring_add_event(req, res, cflags);
+               cflags = io_put_rw_kbuf(req);
+       __io_req_complete(req, res, cflags, cs);
+}
+
+#ifdef CONFIG_BLOCK
+static bool io_resubmit_prep(struct io_kiocb *req, int error)
+{
+       struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
+       ssize_t ret = -ECANCELED;
+       struct iov_iter iter;
+       int rw;
+
+       if (error) {
+               ret = error;
+               goto end_req;
+       }
+
+       switch (req->opcode) {
+       case IORING_OP_READV:
+       case IORING_OP_READ_FIXED:
+       case IORING_OP_READ:
+               rw = READ;
+               break;
+       case IORING_OP_WRITEV:
+       case IORING_OP_WRITE_FIXED:
+       case IORING_OP_WRITE:
+               rw = WRITE;
+               break;
+       default:
+               printk_once(KERN_WARNING "io_uring: bad opcode in resubmit %d\n",
+                               req->opcode);
+               goto end_req;
+       }
+
+       ret = io_import_iovec(rw, req, &iovec, &iter, false);
+       if (ret < 0)
+               goto end_req;
+       ret = io_setup_async_rw(req, ret, iovec, inline_vecs, &iter);
+       if (!ret)
+               return true;
+       kfree(iovec);
+end_req:
+       req_set_fail_links(req);
+       io_req_complete(req, ret);
+       return false;
+}
+
+static void io_rw_resubmit(struct callback_head *cb)
+{
+       struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
+       struct io_ring_ctx *ctx = req->ctx;
+       int err;
+
+       err = io_sq_thread_acquire_mm(ctx, req);
+
+       if (io_resubmit_prep(req, err)) {
+               refcount_inc(&req->refs);
+               io_queue_async_work(req);
+       }
+
+       percpu_ref_put(&ctx->refs);
+}
+#endif
+
+static bool io_rw_reissue(struct io_kiocb *req, long res)
+{
+#ifdef CONFIG_BLOCK
+       int ret;
+
+       if ((res != -EAGAIN && res != -EOPNOTSUPP) || io_wq_current_is_worker())
+               return false;
+
+       init_task_work(&req->task_work, io_rw_resubmit);
+       percpu_ref_get(&req->ctx->refs);
+
+       ret = io_req_task_work_add(req, &req->task_work);
+       if (!ret)
+               return true;
+#endif
+       return false;
+}
+
+static void __io_complete_rw(struct io_kiocb *req, long res, long res2,
+                            struct io_comp_state *cs)
+{
+       if (!io_rw_reissue(req, res))
+               io_complete_rw_common(&req->rw.kiocb, res, cs);
 }
 
 static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
 {
        struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
 
-       io_complete_rw_common(kiocb, res);
-       io_put_req(req);
+       __io_complete_rw(req, res, res2, NULL);
 }
 
 static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
@@ -2026,13 +2389,13 @@ static void io_iopoll_req_issued(struct io_kiocb *req)
         * how we do polling eventually, not spinning if we're on potentially
         * different devices.
         */
-       if (list_empty(&ctx->poll_list)) {
+       if (list_empty(&ctx->iopoll_list)) {
                ctx->poll_multi_file = false;
        } else if (!ctx->poll_multi_file) {
                struct io_kiocb *list_req;
 
-               list_req = list_first_entry(&ctx->poll_list, struct io_kiocb,
-                                               list);
+               list_req = list_first_entry(&ctx->iopoll_list, struct io_kiocb,
+                                               inflight_entry);
                if (list_req->file != req->file)
                        ctx->poll_multi_file = true;
        }
@@ -2042,9 +2405,9 @@ static void io_iopoll_req_issued(struct io_kiocb *req)
         * it to the front so we find it first.
         */
        if (READ_ONCE(req->iopoll_completed))
-               list_add(&req->list, &ctx->poll_list);
+               list_add(&req->inflight_entry, &ctx->iopoll_list);
        else
-               list_add_tail(&req->list, &ctx->poll_list);
+               list_add_tail(&req->inflight_entry, &ctx->iopoll_list);
 
        if ((ctx->flags & IORING_SETUP_SQPOLL) &&
            wq_has_sleeper(&ctx->sqo_wait))
@@ -2053,10 +2416,8 @@ static void io_iopoll_req_issued(struct io_kiocb *req)
 
 static void __io_state_file_put(struct io_submit_state *state)
 {
-       int diff = state->has_refs - state->used_refs;
-
-       if (diff)
-               fput_many(state->file, diff);
+       if (state->has_refs)
+               fput_many(state->file, state->has_refs);
        state->file = NULL;
 }
 
@@ -2078,7 +2439,7 @@ static struct file *__io_file_get(struct io_submit_state *state, int fd)
 
        if (state->file) {
                if (state->fd == fd) {
-                       state->used_refs++;
+                       state->has_refs--;
                        state->ios_left--;
                        return state->file;
                }
@@ -2089,12 +2450,20 @@ static struct file *__io_file_get(struct io_submit_state *state, int fd)
                return NULL;
 
        state->fd = fd;
-       state->has_refs = state->ios_left;
-       state->used_refs = 1;
        state->ios_left--;
+       state->has_refs = state->ios_left;
        return state->file;
 }
 
+static bool io_bdev_nowait(struct block_device *bdev)
+{
+#ifdef CONFIG_BLOCK
+       return !bdev || queue_is_mq(bdev_get_queue(bdev));
+#else
+       return true;
+#endif
+}
+
 /*
  * If we tracked the file through the SCM inflight mechanism, we could support
  * any file. For now, just ensure that anything potentially problematic is done
@@ -2104,10 +2473,19 @@ static bool io_file_supports_async(struct file *file, int rw)
 {
        umode_t mode = file_inode(file)->i_mode;
 
-       if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISSOCK(mode))
-               return true;
-       if (S_ISREG(mode) && file->f_op != &io_uring_fops)
+       if (S_ISBLK(mode)) {
+               if (io_bdev_nowait(file->f_inode->i_bdev))
+                       return true;
+               return false;
+       }
+       if (S_ISCHR(mode) || S_ISSOCK(mode))
                return true;
+       if (S_ISREG(mode)) {
+               if (io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
+                   file->f_op != &io_uring_fops)
+                       return true;
+               return false;
+       }
 
        /* any ->read/write should understand O_NONBLOCK */
        if (file->f_flags & O_NONBLOCK)
@@ -2158,6 +2536,9 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
        if (kiocb->ki_flags & IOCB_NOWAIT)
                req->flags |= REQ_F_NOWAIT;
 
+       if (kiocb->ki_flags & IOCB_DIRECT)
+               io_get_req_task(req);
+
        if (force_nonblock)
                kiocb->ki_flags |= IOCB_NOWAIT;
 
@@ -2168,8 +2549,8 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 
                kiocb->ki_flags |= IOCB_HIPRI;
                kiocb->ki_complete = io_complete_rw_iopoll;
-               req->result = 0;
                req->iopoll_completed = 0;
+               io_get_req_task(req);
        } else {
                if (kiocb->ki_flags & IOCB_HIPRI)
                        return -EINVAL;
@@ -2203,14 +2584,15 @@ static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
        }
 }
 
-static void kiocb_done(struct kiocb *kiocb, ssize_t ret)
+static void kiocb_done(struct kiocb *kiocb, ssize_t ret,
+                      struct io_comp_state *cs)
 {
        struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
 
        if (req->flags & REQ_F_CUR_POS)
                req->file->f_pos = kiocb->ki_pos;
        if (ret >= 0 && kiocb->ki_complete == io_complete_rw)
-               io_complete_rw(kiocb, ret, 0);
+               __io_complete_rw(req, ret, 0, cs);
        else
                io_rw_done(kiocb, ret);
 }
@@ -2466,10 +2848,8 @@ static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
        if (req->io) {
                struct io_async_rw *iorw = &req->io->rw;
 
-               *iovec = iorw->iov;
-               iov_iter_init(iter, rw, *iovec, iorw->nr_segs, iorw->size);
-               if (iorw->iov == iorw->fast_iov)
-                       *iovec = NULL;
+               iov_iter_init(iter, rw, iorw->iov, iorw->nr_segs, iorw->size);
+               *iovec = NULL;
                return iorw->size;
        }
 
@@ -2554,15 +2934,17 @@ static void io_req_map_rw(struct io_kiocb *req, ssize_t io_size,
                          struct iovec *iovec, struct iovec *fast_iov,
                          struct iov_iter *iter)
 {
-       req->io->rw.nr_segs = iter->nr_segs;
-       req->io->rw.size = io_size;
-       req->io->rw.iov = iovec;
-       if (!req->io->rw.iov) {
-               req->io->rw.iov = req->io->rw.fast_iov;
-               if (req->io->rw.iov != fast_iov)
-                       memcpy(req->io->rw.iov, fast_iov,
+       struct io_async_rw *rw = &req->io->rw;
+
+       rw->nr_segs = iter->nr_segs;
+       rw->size = io_size;
+       if (!iovec) {
+               rw->iov = rw->fast_iov;
+               if (rw->iov != fast_iov)
+                       memcpy(rw->iov, fast_iov,
                               sizeof(struct iovec) * iter->nr_segs);
        } else {
+               rw->iov = iovec;
                req->flags |= REQ_F_NEED_CLEANUP;
        }
 }
@@ -2581,107 +2963,239 @@ static int io_alloc_async_ctx(struct io_kiocb *req)
        return  __io_alloc_async_ctx(req);
 }
 
-static int io_setup_async_rw(struct io_kiocb *req, ssize_t io_size,
-                            struct iovec *iovec, struct iovec *fast_iov,
-                            struct iov_iter *iter)
+static int io_setup_async_rw(struct io_kiocb *req, ssize_t io_size,
+                            struct iovec *iovec, struct iovec *fast_iov,
+                            struct iov_iter *iter)
+{
+       if (!io_op_defs[req->opcode].async_ctx)
+               return 0;
+       if (!req->io) {
+               if (__io_alloc_async_ctx(req))
+                       return -ENOMEM;
+
+               io_req_map_rw(req, io_size, iovec, fast_iov, iter);
+       }
+       return 0;
+}
+
+static inline int io_rw_prep_async(struct io_kiocb *req, int rw,
+                                  bool force_nonblock)
+{
+       struct io_async_ctx *io = req->io;
+       struct iov_iter iter;
+       ssize_t ret;
+
+       io->rw.iov = io->rw.fast_iov;
+       req->io = NULL;
+       ret = io_import_iovec(rw, req, &io->rw.iov, &iter, !force_nonblock);
+       req->io = io;
+       if (unlikely(ret < 0))
+               return ret;
+
+       io_req_map_rw(req, ret, io->rw.iov, io->rw.fast_iov, &iter);
+       return 0;
+}
+
+static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
+                       bool force_nonblock)
+{
+       ssize_t ret;
+
+       ret = io_prep_rw(req, sqe, force_nonblock);
+       if (ret)
+               return ret;
+
+       if (unlikely(!(req->file->f_mode & FMODE_READ)))
+               return -EBADF;
+
+       /* either don't need iovec imported or already have it */
+       if (!req->io || req->flags & REQ_F_NEED_CLEANUP)
+               return 0;
+       return io_rw_prep_async(req, READ, force_nonblock);
+}
+
+/*
+ * This is our waitqueue callback handler, registered through lock_page_async()
+ * when we initially tried to do the IO with the iocb armed our waitqueue.
+ * This gets called when the page is unlocked, and we generally expect that to
+ * happen when the page IO is completed and the page is now uptodate. This will
+ * queue a task_work based retry of the operation, attempting to copy the data
+ * again. If the latter fails because the page was NOT uptodate, then we will
+ * do a thread based blocking retry of the operation. That's the unexpected
+ * slow path.
+ */
+static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
+                            int sync, void *arg)
+{
+       struct wait_page_queue *wpq;
+       struct io_kiocb *req = wait->private;
+       struct wait_page_key *key = arg;
+       int ret;
+
+       wpq = container_of(wait, struct wait_page_queue, wait);
+
+       if (!wake_page_match(wpq, key))
+               return 0;
+
+       list_del_init(&wait->entry);
+
+       init_task_work(&req->task_work, io_req_task_submit);
+       percpu_ref_get(&req->ctx->refs);
+
+       /* submit ref gets dropped, acquire a new one */
+       refcount_inc(&req->refs);
+       ret = io_req_task_work_add(req, &req->task_work);
+       if (unlikely(ret)) {
+               struct task_struct *tsk;
+
+               /* queue just for cancelation */
+               init_task_work(&req->task_work, io_req_task_cancel);
+               tsk = io_wq_get_task(req->ctx->io_wq);
+               task_work_add(tsk, &req->task_work, 0);
+               wake_up_process(tsk);
+       }
+       return 1;
+}
+
+static inline int kiocb_wait_page_queue_init(struct kiocb *kiocb,
+                                            struct wait_page_queue *wait,
+                                            wait_queue_func_t func,
+                                            void *data)
 {
-       if (!io_op_defs[req->opcode].async_ctx)
+       /* Can't support async wakeup with polled IO */
+       if (kiocb->ki_flags & IOCB_HIPRI)
+               return -EINVAL;
+       if (kiocb->ki_filp->f_mode & FMODE_BUF_RASYNC) {
+               wait->wait.func = func;
+               wait->wait.private = data;
+               wait->wait.flags = 0;
+               INIT_LIST_HEAD(&wait->wait.entry);
+               kiocb->ki_flags |= IOCB_WAITQ;
+               kiocb->ki_waitq = wait;
                return 0;
-       if (!req->io) {
-               if (__io_alloc_async_ctx(req))
-                       return -ENOMEM;
-
-               io_req_map_rw(req, io_size, iovec, fast_iov, iter);
        }
-       return 0;
+
+       return -EOPNOTSUPP;
 }
 
-static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
-                       bool force_nonblock)
+/*
+ * This controls whether a given IO request should be armed for async page
+ * based retry. If we return false here, the request is handed to the async
+ * worker threads for retry. If we're doing buffered reads on a regular file,
+ * we prepare a private wait_page_queue entry and retry the operation. This
+ * will either succeed because the page is now uptodate and unlocked, or it
+ * will register a callback when the page is unlocked at IO completion. Through
+ * that callback, io_uring uses task_work to setup a retry of the operation.
+ * That retry will attempt the buffered read again. The retry will generally
+ * succeed, or in rare cases where it fails, we then fall back to using the
+ * async worker threads for a blocking retry.
+ */
+static bool io_rw_should_retry(struct io_kiocb *req)
 {
-       struct io_async_ctx *io;
-       struct iov_iter iter;
-       ssize_t ret;
+       struct kiocb *kiocb = &req->rw.kiocb;
+       int ret;
 
-       ret = io_prep_rw(req, sqe, force_nonblock);
-       if (ret)
-               return ret;
+       /* never retry for NOWAIT, we just complete with -EAGAIN */
+       if (req->flags & REQ_F_NOWAIT)
+               return false;
 
-       if (unlikely(!(req->file->f_mode & FMODE_READ)))
-               return -EBADF;
+       /* already tried, or we're doing O_DIRECT */
+       if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_WAITQ))
+               return false;
+       /*
+        * just use poll if we can, and don't attempt if the fs doesn't
+        * support callback based unlocks
+        */
+       if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
+               return false;
 
-       /* either don't need iovec imported or already have it */
-       if (!req->io || req->flags & REQ_F_NEED_CLEANUP)
-               return 0;
+       /*
+        * If request type doesn't require req->io to defer in general,
+        * we need to allocate it here
+        */
+       if (!req->io && __io_alloc_async_ctx(req))
+               return false;
 
-       io = req->io;
-       io->rw.iov = io->rw.fast_iov;
-       req->io = NULL;
-       ret = io_import_iovec(READ, req, &io->rw.iov, &iter, !force_nonblock);
-       req->io = io;
-       if (ret < 0)
-               return ret;
+       ret = kiocb_wait_page_queue_init(kiocb, &req->io->rw.wpq,
+                                               io_async_buf_func, req);
+       if (!ret) {
+               io_get_req_task(req);
+               return true;
+       }
 
-       io_req_map_rw(req, ret, io->rw.iov, io->rw.fast_iov, &iter);
-       return 0;
+       return false;
+}
+
+static int io_iter_do_read(struct io_kiocb *req, struct iov_iter *iter)
+{
+       if (req->file->f_op->read_iter)
+               return call_read_iter(req->file, &req->rw.kiocb, iter);
+       else if (req->file->f_op->read)
+               return loop_rw_iter(READ, req->file, &req->rw.kiocb, iter);
+       else
+               return -EINVAL;
 }
 
-static int io_read(struct io_kiocb *req, bool force_nonblock)
+static int io_read(struct io_kiocb *req, bool force_nonblock,
+                  struct io_comp_state *cs)
 {
        struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
        struct kiocb *kiocb = &req->rw.kiocb;
        struct iov_iter iter;
        size_t iov_count;
-       ssize_t io_size, ret;
+       ssize_t io_size, ret, ret2;
+       unsigned long nr_segs;
 
        ret = io_import_iovec(READ, req, &iovec, &iter, !force_nonblock);
        if (ret < 0)
                return ret;
+       io_size = ret;
+       req->result = io_size;
 
        /* Ensure we clear previously set non-block flag */
        if (!force_nonblock)
                kiocb->ki_flags &= ~IOCB_NOWAIT;
 
-       req->result = 0;
-       io_size = ret;
-       if (req->flags & REQ_F_LINK_HEAD)
-               req->result = io_size;
-
-       /*
-        * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
-        * we know to async punt it even if it was opened O_NONBLOCK
-        */
+       /* If the file doesn't support async, just async punt */
        if (force_nonblock && !io_file_supports_async(req->file, READ))
                goto copy_iov;
 
        iov_count = iov_iter_count(&iter);
+       nr_segs = iter.nr_segs;
        ret = rw_verify_area(READ, req->file, &kiocb->ki_pos, iov_count);
-       if (!ret) {
-               ssize_t ret2;
+       if (unlikely(ret))
+               goto out_free;
 
-               if (req->file->f_op->read_iter)
-                       ret2 = call_read_iter(req->file, kiocb, &iter);
-               else
-                       ret2 = loop_rw_iter(READ, req->file, kiocb, &iter);
+       ret2 = io_iter_do_read(req, &iter);
 
-               /* Catch -EAGAIN return for forced non-blocking submission */
-               if (!force_nonblock || ret2 != -EAGAIN) {
-                       kiocb_done(kiocb, ret2);
-               } else {
+       /* Catch -EAGAIN return for forced non-blocking submission */
+       if (!force_nonblock || (ret2 != -EAGAIN && ret2 != -EIO)) {
+               kiocb_done(kiocb, ret2, cs);
+       } else {
+               iter.count = iov_count;
+               iter.nr_segs = nr_segs;
 copy_iov:
-                       ret = io_setup_async_rw(req, io_size, iovec,
-                                               inline_vecs, &iter);
-                       if (ret)
+               ret = io_setup_async_rw(req, io_size, iovec, inline_vecs,
+                                       &iter);
+               if (ret)
+                       goto out_free;
+               /* it's copied and will be cleaned with ->io */
+               iovec = NULL;
+               /* if we can retry, do so with the callbacks armed */
+               if (io_rw_should_retry(req)) {
+                       ret2 = io_iter_do_read(req, &iter);
+                       if (ret2 == -EIOCBQUEUED) {
                                goto out_free;
-                       /* any defer here is final, must blocking retry */
-                       if (!(req->flags & REQ_F_NOWAIT) &&
-                           !file_can_poll(req->file))
-                               req->flags |= REQ_F_MUST_PUNT;
-                       return -EAGAIN;
+                       } else if (ret2 != -EAGAIN) {
+                               kiocb_done(kiocb, ret2, cs);
+                               goto out_free;
+                       }
                }
+               kiocb->ki_flags &= ~IOCB_WAITQ;
+               return -EAGAIN;
        }
 out_free:
-       if (!(req->flags & REQ_F_NEED_CLEANUP))
+       if (iovec)
                kfree(iovec);
        return ret;
 }
@@ -2689,8 +3203,6 @@ out_free:
 static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                         bool force_nonblock)
 {
-       struct io_async_ctx *io;
-       struct iov_iter iter;
        ssize_t ret;
 
        ret = io_prep_rw(req, sqe, force_nonblock);
@@ -2700,49 +3212,33 @@ static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
        if (unlikely(!(req->file->f_mode & FMODE_WRITE)))
                return -EBADF;
 
-       req->fsize = rlimit(RLIMIT_FSIZE);
-
        /* either don't need iovec imported or already have it */
        if (!req->io || req->flags & REQ_F_NEED_CLEANUP)
                return 0;
-
-       io = req->io;
-       io->rw.iov = io->rw.fast_iov;
-       req->io = NULL;
-       ret = io_import_iovec(WRITE, req, &io->rw.iov, &iter, !force_nonblock);
-       req->io = io;
-       if (ret < 0)
-               return ret;
-
-       io_req_map_rw(req, ret, io->rw.iov, io->rw.fast_iov, &iter);
-       return 0;
+       return io_rw_prep_async(req, WRITE, force_nonblock);
 }
 
-static int io_write(struct io_kiocb *req, bool force_nonblock)
+static int io_write(struct io_kiocb *req, bool force_nonblock,
+                   struct io_comp_state *cs)
 {
        struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
        struct kiocb *kiocb = &req->rw.kiocb;
        struct iov_iter iter;
        size_t iov_count;
-       ssize_t ret, io_size;
+       ssize_t ret, ret2, io_size;
+       unsigned long nr_segs;
 
        ret = io_import_iovec(WRITE, req, &iovec, &iter, !force_nonblock);
        if (ret < 0)
                return ret;
+       io_size = ret;
+       req->result = io_size;
 
        /* Ensure we clear previously set non-block flag */
        if (!force_nonblock)
                req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT;
 
-       req->result = 0;
-       io_size = ret;
-       if (req->flags & REQ_F_LINK_HEAD)
-               req->result = io_size;
-
-       /*
-        * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
-        * we know to async punt it even if it was opened O_NONBLOCK
-        */
+       /* If the file doesn't support async, just async punt */
        if (force_nonblock && !io_file_supports_async(req->file, WRITE))
                goto copy_iov;
 
@@ -2752,59 +3248,55 @@ static int io_write(struct io_kiocb *req, bool force_nonblock)
                goto copy_iov;
 
        iov_count = iov_iter_count(&iter);
+       nr_segs = iter.nr_segs;
        ret = rw_verify_area(WRITE, req->file, &kiocb->ki_pos, iov_count);
-       if (!ret) {
-               ssize_t ret2;
-
-               /*
-                * Open-code file_start_write here to grab freeze protection,
-                * which will be released by another thread in
-                * io_complete_rw().  Fool lockdep by telling it the lock got
-                * released so that it doesn't complain about the held lock when
-                * we return to userspace.
-                */
-               if (req->flags & REQ_F_ISREG) {
-                       __sb_start_write(file_inode(req->file)->i_sb,
-                                               SB_FREEZE_WRITE, true);
-                       __sb_writers_release(file_inode(req->file)->i_sb,
-                                               SB_FREEZE_WRITE);
-               }
-               kiocb->ki_flags |= IOCB_WRITE;
-
-               if (!force_nonblock)
-                       current->signal->rlim[RLIMIT_FSIZE].rlim_cur = req->fsize;
+       if (unlikely(ret))
+               goto out_free;
 
-               if (req->file->f_op->write_iter)
-                       ret2 = call_write_iter(req->file, kiocb, &iter);
-               else
-                       ret2 = loop_rw_iter(WRITE, req->file, kiocb, &iter);
+       /*
+        * Open-code file_start_write here to grab freeze protection,
+        * which will be released by another thread in
+        * io_complete_rw().  Fool lockdep by telling it the lock got
+        * released so that it doesn't complain about the held lock when
+        * we return to userspace.
+        */
+       if (req->flags & REQ_F_ISREG) {
+               __sb_start_write(file_inode(req->file)->i_sb,
+                                       SB_FREEZE_WRITE, true);
+               __sb_writers_release(file_inode(req->file)->i_sb,
+                                       SB_FREEZE_WRITE);
+       }
+       kiocb->ki_flags |= IOCB_WRITE;
 
-               if (!force_nonblock)
-                       current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
+       if (req->file->f_op->write_iter)
+               ret2 = call_write_iter(req->file, kiocb, &iter);
+       else if (req->file->f_op->write)
+               ret2 = loop_rw_iter(WRITE, req->file, kiocb, &iter);
+       else
+               ret2 = -EINVAL;
 
-               /*
-                * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
-                * retry them without IOCB_NOWAIT.
-                */
-               if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
-                       ret2 = -EAGAIN;
-               if (!force_nonblock || ret2 != -EAGAIN) {
-                       kiocb_done(kiocb, ret2);
-               } else {
+       /*
+        * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
+        * retry them without IOCB_NOWAIT.
+        */
+       if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
+               ret2 = -EAGAIN;
+       if (!force_nonblock || ret2 != -EAGAIN) {
+               kiocb_done(kiocb, ret2, cs);
+       } else {
+               iter.count = iov_count;
+               iter.nr_segs = nr_segs;
 copy_iov:
-                       ret = io_setup_async_rw(req, io_size, iovec,
-                                               inline_vecs, &iter);
-                       if (ret)
-                               goto out_free;
-                       /* any defer here is final, must blocking retry */
-                       if (!(req->flags & REQ_F_NOWAIT) &&
-                           !file_can_poll(req->file))
-                               req->flags |= REQ_F_MUST_PUNT;
-                       return -EAGAIN;
-               }
+               ret = io_setup_async_rw(req, io_size, iovec, inline_vecs,
+                                       &iter);
+               if (ret)
+                       goto out_free;
+               /* it's copied and will be cleaned with ->io */
+               iovec = NULL;
+               return -EAGAIN;
        }
 out_free:
-       if (!(req->flags & REQ_F_NEED_CLEANUP))
+       if (iovec)
                kfree(iovec);
        return ret;
 }
@@ -2870,10 +3362,9 @@ static int io_tee(struct io_kiocb *req, bool force_nonblock)
        io_put_file(req, in, (sp->flags & SPLICE_F_FD_IN_FIXED));
        req->flags &= ~REQ_F_NEED_CLEANUP;
 
-       io_cqring_add_event(req, ret);
        if (ret != sp->len)
                req_set_fail_links(req);
-       io_put_req(req);
+       io_req_complete(req, ret);
        return 0;
 }
 
@@ -2907,25 +3398,23 @@ static int io_splice(struct io_kiocb *req, bool force_nonblock)
        io_put_file(req, in, (sp->flags & SPLICE_F_FD_IN_FIXED));
        req->flags &= ~REQ_F_NEED_CLEANUP;
 
-       io_cqring_add_event(req, ret);
        if (ret != sp->len)
                req_set_fail_links(req);
-       io_put_req(req);
+       io_req_complete(req, ret);
        return 0;
 }
 
 /*
  * IORING_OP_NOP just posts a completion event, nothing else.
  */
-static int io_nop(struct io_kiocb *req)
+static int io_nop(struct io_kiocb *req, struct io_comp_state *cs)
 {
        struct io_ring_ctx *ctx = req->ctx;
 
        if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
                return -EINVAL;
 
-       io_cqring_add_event(req, 0);
-       io_put_req(req);
+       __io_req_complete(req, 0, 0, cs);
        return 0;
 }
 
@@ -2964,8 +3453,7 @@ static int io_fsync(struct io_kiocb *req, bool force_nonblock)
                                req->sync.flags & IORING_FSYNC_DATASYNC);
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       io_req_complete(req, ret);
        return 0;
 }
 
@@ -2980,7 +3468,6 @@ static int io_fallocate_prep(struct io_kiocb *req,
        req->sync.off = READ_ONCE(sqe->off);
        req->sync.len = READ_ONCE(sqe->addr);
        req->sync.mode = READ_ONCE(sqe->len);
-       req->fsize = rlimit(RLIMIT_FSIZE);
        return 0;
 }
 
@@ -2991,15 +3478,11 @@ static int io_fallocate(struct io_kiocb *req, bool force_nonblock)
        /* fallocate always requiring blocking context */
        if (force_nonblock)
                return -EAGAIN;
-
-       current->signal->rlim[RLIMIT_FSIZE].rlim_cur = req->fsize;
        ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off,
                                req->sync.len);
-       current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       io_req_complete(req, ret);
        return 0;
 }
 
@@ -3095,8 +3578,7 @@ err:
        req->flags &= ~REQ_F_NEED_CLEANUP;
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       io_req_complete(req, ret);
        return 0;
 }
 
@@ -3150,7 +3632,8 @@ static int __io_remove_buffers(struct io_ring_ctx *ctx, struct io_buffer *buf,
        return i;
 }
 
-static int io_remove_buffers(struct io_kiocb *req, bool force_nonblock)
+static int io_remove_buffers(struct io_kiocb *req, bool force_nonblock,
+                            struct io_comp_state *cs)
 {
        struct io_provide_buf *p = &req->pbuf;
        struct io_ring_ctx *ctx = req->ctx;
@@ -3169,8 +3652,7 @@ static int io_remove_buffers(struct io_kiocb *req, bool force_nonblock)
        io_ring_submit_lock(ctx, !force_nonblock);
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       __io_req_complete(req, ret, 0, cs);
        return 0;
 }
 
@@ -3228,7 +3710,8 @@ static int io_add_buffers(struct io_provide_buf *pbuf, struct io_buffer **head)
        return i ? i : -ENOMEM;
 }
 
-static int io_provide_buffers(struct io_kiocb *req, bool force_nonblock)
+static int io_provide_buffers(struct io_kiocb *req, bool force_nonblock,
+                             struct io_comp_state *cs)
 {
        struct io_provide_buf *p = &req->pbuf;
        struct io_ring_ctx *ctx = req->ctx;
@@ -3257,8 +3740,7 @@ out:
        io_ring_submit_unlock(ctx, !force_nonblock);
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       __io_req_complete(req, ret, 0, cs);
        return 0;
 }
 
@@ -3289,7 +3771,8 @@ static int io_epoll_ctl_prep(struct io_kiocb *req,
 #endif
 }
 
-static int io_epoll_ctl(struct io_kiocb *req, bool force_nonblock)
+static int io_epoll_ctl(struct io_kiocb *req, bool force_nonblock,
+                       struct io_comp_state *cs)
 {
 #if defined(CONFIG_EPOLL)
        struct io_epoll *ie = &req->epoll;
@@ -3301,8 +3784,7 @@ static int io_epoll_ctl(struct io_kiocb *req, bool force_nonblock)
 
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       __io_req_complete(req, ret, 0, cs);
        return 0;
 #else
        return -EOPNOTSUPP;
@@ -3338,8 +3820,7 @@ static int io_madvise(struct io_kiocb *req, bool force_nonblock)
        ret = do_madvise(ma->addr, ma->len, ma->advice);
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       io_req_complete(req, ret);
        return 0;
 #else
        return -EOPNOTSUPP;
@@ -3378,8 +3859,7 @@ static int io_fadvise(struct io_kiocb *req, bool force_nonblock)
        ret = vfs_fadvise(req->file, fa->offset, fa->len, fa->advice);
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       io_req_complete(req, ret);
        return 0;
 }
 
@@ -3418,8 +3898,7 @@ static int io_statx(struct io_kiocb *req, bool force_nonblock)
 
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       io_req_complete(req, ret);
        return 0;
 }
 
@@ -3450,7 +3929,8 @@ static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
        return 0;
 }
 
-static int io_close(struct io_kiocb *req, bool force_nonblock)
+static int io_close(struct io_kiocb *req, bool force_nonblock,
+                   struct io_comp_state *cs)
 {
        struct io_close *close = &req->close;
        int ret;
@@ -3464,8 +3944,10 @@ static int io_close(struct io_kiocb *req, bool force_nonblock)
 
        /* if the file has a flush method, be safe and punt to async */
        if (close->put_file->f_op->flush && force_nonblock) {
+               /* was never set, but play safe */
+               req->flags &= ~REQ_F_NOWAIT;
                /* avoid grabbing files - we don't need the files */
-               req->flags |= REQ_F_NO_FILE_TABLE | REQ_F_MUST_PUNT;
+               req->flags |= REQ_F_NO_FILE_TABLE;
                return -EAGAIN;
        }
 
@@ -3473,10 +3955,9 @@ static int io_close(struct io_kiocb *req, bool force_nonblock)
        ret = filp_close(close->put_file, req->work.files);
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
        fput(close->put_file);
        close->put_file = NULL;
-       io_put_req(req);
+       __io_req_complete(req, ret, 0, cs);
        return 0;
 }
 
@@ -3510,8 +3991,7 @@ static int io_sync_file_range(struct io_kiocb *req, bool force_nonblock)
                                req->sync.flags);
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       io_req_complete(req, ret);
        return 0;
 }
 
@@ -3531,6 +4011,15 @@ static int io_setup_async_msg(struct io_kiocb *req,
        return -EAGAIN;
 }
 
+static int io_sendmsg_copy_hdr(struct io_kiocb *req,
+                              struct io_async_msghdr *iomsg)
+{
+       iomsg->iov = iomsg->fast_iov;
+       iomsg->msg.msg_name = &iomsg->addr;
+       return sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg,
+                                  req->sr_msg.msg_flags, &iomsg->iov);
+}
+
 static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
        struct io_sr_msg *sr = &req->sr_msg;
@@ -3541,7 +4030,7 @@ static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
                return -EINVAL;
 
        sr->msg_flags = READ_ONCE(sqe->msg_flags);
-       sr->msg = u64_to_user_ptr(READ_ONCE(sqe->addr));
+       sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
        sr->len = READ_ONCE(sqe->len);
 
 #ifdef CONFIG_COMPAT
@@ -3555,136 +4044,126 @@ static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
        if (req->flags & REQ_F_NEED_CLEANUP)
                return 0;
 
-       io->msg.msg.msg_name = &io->msg.addr;
-       io->msg.iov = io->msg.fast_iov;
-       ret = sendmsg_copy_msghdr(&io->msg.msg, sr->msg, sr->msg_flags,
-                                       &io->msg.iov);
+       ret = io_sendmsg_copy_hdr(req, &io->msg);
        if (!ret)
                req->flags |= REQ_F_NEED_CLEANUP;
        return ret;
 }
 
-static int io_sendmsg(struct io_kiocb *req, bool force_nonblock)
+static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
+                     struct io_comp_state *cs)
 {
-       struct io_async_msghdr *kmsg = NULL;
+       struct io_async_msghdr iomsg, *kmsg;
        struct socket *sock;
+       unsigned flags;
        int ret;
 
        sock = sock_from_file(req->file, &ret);
-       if (sock) {
-               struct io_async_ctx io;
-               unsigned flags;
-
-               if (req->io) {
-                       kmsg = &req->io->msg;
-                       kmsg->msg.msg_name = &req->io->msg.addr;
-                       /* if iov is set, it's allocated already */
-                       if (!kmsg->iov)
-                               kmsg->iov = kmsg->fast_iov;
-                       kmsg->msg.msg_iter.iov = kmsg->iov;
-               } else {
-                       struct io_sr_msg *sr = &req->sr_msg;
-
-                       kmsg = &io.msg;
-                       kmsg->msg.msg_name = &io.msg.addr;
+       if (unlikely(!sock))
+               return ret;
 
-                       io.msg.iov = io.msg.fast_iov;
-                       ret = sendmsg_copy_msghdr(&io.msg.msg, sr->msg,
-                                       sr->msg_flags, &io.msg.iov);
-                       if (ret)
-                               return ret;
-               }
+       if (req->io) {
+               kmsg = &req->io->msg;
+               kmsg->msg.msg_name = &req->io->msg.addr;
+               /* if iov is set, it's allocated already */
+               if (!kmsg->iov)
+                       kmsg->iov = kmsg->fast_iov;
+               kmsg->msg.msg_iter.iov = kmsg->iov;
+       } else {
+               ret = io_sendmsg_copy_hdr(req, &iomsg);
+               if (ret)
+                       return ret;
+               kmsg = &iomsg;
+       }
 
-               flags = req->sr_msg.msg_flags;
-               if (flags & MSG_DONTWAIT)
-                       req->flags |= REQ_F_NOWAIT;
-               else if (force_nonblock)
-                       flags |= MSG_DONTWAIT;
+       flags = req->sr_msg.msg_flags;
+       if (flags & MSG_DONTWAIT)
+               req->flags |= REQ_F_NOWAIT;
+       else if (force_nonblock)
+               flags |= MSG_DONTWAIT;
 
-               ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
-               if (force_nonblock && ret == -EAGAIN)
-                       return io_setup_async_msg(req, kmsg);
-               if (ret == -ERESTARTSYS)
-                       ret = -EINTR;
-       }
+       ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
+       if (force_nonblock && ret == -EAGAIN)
+               return io_setup_async_msg(req, kmsg);
+       if (ret == -ERESTARTSYS)
+               ret = -EINTR;
 
-       if (kmsg && kmsg->iov != kmsg->fast_iov)
+       if (kmsg->iov != kmsg->fast_iov)
                kfree(kmsg->iov);
        req->flags &= ~REQ_F_NEED_CLEANUP;
-       io_cqring_add_event(req, ret);
        if (ret < 0)
                req_set_fail_links(req);
-       io_put_req(req);
+       __io_req_complete(req, ret, 0, cs);
        return 0;
 }
 
-static int io_send(struct io_kiocb *req, bool force_nonblock)
+static int io_send(struct io_kiocb *req, bool force_nonblock,
+                  struct io_comp_state *cs)
 {
+       struct io_sr_msg *sr = &req->sr_msg;
+       struct msghdr msg;
+       struct iovec iov;
        struct socket *sock;
+       unsigned flags;
        int ret;
 
        sock = sock_from_file(req->file, &ret);
-       if (sock) {
-               struct io_sr_msg *sr = &req->sr_msg;
-               struct msghdr msg;
-               struct iovec iov;
-               unsigned flags;
+       if (unlikely(!sock))
+               return ret;
 
-               ret = import_single_range(WRITE, sr->buf, sr->len, &iov,
-                                               &msg.msg_iter);
-               if (ret)
-                       return ret;
+       ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter);
+       if (unlikely(ret))
+               return ret;;
 
-               msg.msg_name = NULL;
-               msg.msg_control = NULL;
-               msg.msg_controllen = 0;
-               msg.msg_namelen = 0;
+       msg.msg_name = NULL;
+       msg.msg_control = NULL;
+       msg.msg_controllen = 0;
+       msg.msg_namelen = 0;
 
-               flags = req->sr_msg.msg_flags;
-               if (flags & MSG_DONTWAIT)
-                       req->flags |= REQ_F_NOWAIT;
-               else if (force_nonblock)
-                       flags |= MSG_DONTWAIT;
+       flags = req->sr_msg.msg_flags;
+       if (flags & MSG_DONTWAIT)
+               req->flags |= REQ_F_NOWAIT;
+       else if (force_nonblock)
+               flags |= MSG_DONTWAIT;
 
-               msg.msg_flags = flags;
-               ret = sock_sendmsg(sock, &msg);
-               if (force_nonblock && ret == -EAGAIN)
-                       return -EAGAIN;
-               if (ret == -ERESTARTSYS)
-                       ret = -EINTR;
-       }
+       msg.msg_flags = flags;
+       ret = sock_sendmsg(sock, &msg);
+       if (force_nonblock && ret == -EAGAIN)
+               return -EAGAIN;
+       if (ret == -ERESTARTSYS)
+               ret = -EINTR;
 
-       io_cqring_add_event(req, ret);
        if (ret < 0)
                req_set_fail_links(req);
-       io_put_req(req);
+       __io_req_complete(req, ret, 0, cs);
        return 0;
 }
 
-static int __io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_ctx *io)
+static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
+                                struct io_async_msghdr *iomsg)
 {
        struct io_sr_msg *sr = &req->sr_msg;
        struct iovec __user *uiov;
        size_t iov_len;
        int ret;
 
-       ret = __copy_msghdr_from_user(&io->msg.msg, sr->msg, &io->msg.uaddr,
-                                       &uiov, &iov_len);
+       ret = __copy_msghdr_from_user(&iomsg->msg, sr->umsg,
+                                       &iomsg->uaddr, &uiov, &iov_len);
        if (ret)
                return ret;
 
        if (req->flags & REQ_F_BUFFER_SELECT) {
                if (iov_len > 1)
                        return -EINVAL;
-               if (copy_from_user(io->msg.iov, uiov, sizeof(*uiov)))
+               if (copy_from_user(iomsg->iov, uiov, sizeof(*uiov)))
                        return -EFAULT;
-               sr->len = io->msg.iov[0].iov_len;
-               iov_iter_init(&io->msg.msg.msg_iter, READ, io->msg.iov, 1,
+               sr->len = iomsg->iov[0].iov_len;
+               iov_iter_init(&iomsg->msg.msg_iter, READ, iomsg->iov, 1,
                                sr->len);
-               io->msg.iov = NULL;
+               iomsg->iov = NULL;
        } else {
                ret = import_iovec(READ, uiov, iov_len, UIO_FASTIOV,
-                                       &io->msg.iov, &io->msg.msg.msg_iter);
+                                       &iomsg->iov, &iomsg->msg.msg_iter);
                if (ret > 0)
                        ret = 0;
        }
@@ -3694,7 +4173,7 @@ static int __io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_ctx *io)
 
 #ifdef CONFIG_COMPAT
 static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
-                                       struct io_async_ctx *io)
+                                       struct io_async_msghdr *iomsg)
 {
        struct compat_msghdr __user *msg_compat;
        struct io_sr_msg *sr = &req->sr_msg;
@@ -3703,8 +4182,8 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
        compat_size_t len;
        int ret;
 
-       msg_compat = (struct compat_msghdr __user *) sr->msg;
-       ret = __get_compat_msghdr(&io->msg.msg, msg_compat, &io->msg.uaddr,
+       msg_compat = (struct compat_msghdr __user *) sr->umsg;
+       ret = __get_compat_msghdr(&iomsg->msg, msg_compat, &iomsg->uaddr,
                                        &ptr, &len);
        if (ret)
                return ret;
@@ -3721,12 +4200,12 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
                        return -EFAULT;
                if (clen < 0)
                        return -EINVAL;
-               sr->len = io->msg.iov[0].iov_len;
-               io->msg.iov = NULL;
+               sr->len = iomsg->iov[0].iov_len;
+               iomsg->iov = NULL;
        } else {
                ret = compat_import_iovec(READ, uiov, len, UIO_FASTIOV,
-                                               &io->msg.iov,
-                                               &io->msg.msg.msg_iter);
+                                               &iomsg->iov,
+                                               &iomsg->msg.msg_iter);
                if (ret < 0)
                        return ret;
        }
@@ -3735,40 +4214,40 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
 }
 #endif
 
-static int io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_ctx *io)
+static int io_recvmsg_copy_hdr(struct io_kiocb *req,
+                              struct io_async_msghdr *iomsg)
 {
-       io->msg.msg.msg_name = &io->msg.addr;
-       io->msg.iov = io->msg.fast_iov;
+       iomsg->msg.msg_name = &iomsg->addr;
+       iomsg->iov = iomsg->fast_iov;
 
 #ifdef CONFIG_COMPAT
        if (req->ctx->compat)
-               return __io_compat_recvmsg_copy_hdr(req, io);
+               return __io_compat_recvmsg_copy_hdr(req, iomsg);
 #endif
 
-       return __io_recvmsg_copy_hdr(req, io);
+       return __io_recvmsg_copy_hdr(req, iomsg);
 }
 
 static struct io_buffer *io_recv_buffer_select(struct io_kiocb *req,
-                                              int *cflags, bool needs_lock)
+                                              bool needs_lock)
 {
        struct io_sr_msg *sr = &req->sr_msg;
        struct io_buffer *kbuf;
 
-       if (!(req->flags & REQ_F_BUFFER_SELECT))
-               return NULL;
-
        kbuf = io_buffer_select(req, &sr->len, sr->bgid, sr->kbuf, needs_lock);
        if (IS_ERR(kbuf))
                return kbuf;
 
        sr->kbuf = kbuf;
        req->flags |= REQ_F_BUFFER_SELECTED;
-
-       *cflags = kbuf->bid << IORING_CQE_BUFFER_SHIFT;
-       *cflags |= IORING_CQE_F_BUFFER;
        return kbuf;
 }
 
+static inline unsigned int io_put_recv_kbuf(struct io_kiocb *req)
+{
+       return io_put_kbuf(req, req->sr_msg.kbuf);
+}
+
 static int io_recvmsg_prep(struct io_kiocb *req,
                           const struct io_uring_sqe *sqe)
 {
@@ -3780,7 +4259,7 @@ static int io_recvmsg_prep(struct io_kiocb *req,
                return -EINVAL;
 
        sr->msg_flags = READ_ONCE(sqe->msg_flags);
-       sr->msg = u64_to_user_ptr(READ_ONCE(sqe->addr));
+       sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
        sr->len = READ_ONCE(sqe->len);
        sr->bgid = READ_ONCE(sqe->buf_group);
 
@@ -3795,133 +4274,123 @@ static int io_recvmsg_prep(struct io_kiocb *req,
        if (req->flags & REQ_F_NEED_CLEANUP)
                return 0;
 
-       ret = io_recvmsg_copy_hdr(req, io);
+       ret = io_recvmsg_copy_hdr(req, &io->msg);
        if (!ret)
                req->flags |= REQ_F_NEED_CLEANUP;
        return ret;
 }
 
-static int io_recvmsg(struct io_kiocb *req, bool force_nonblock)
+static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
+                     struct io_comp_state *cs)
 {
-       struct io_async_msghdr *kmsg = NULL;
+       struct io_async_msghdr iomsg, *kmsg;
        struct socket *sock;
+       struct io_buffer *kbuf;
+       unsigned flags;
        int ret, cflags = 0;
 
        sock = sock_from_file(req->file, &ret);
-       if (sock) {
-               struct io_buffer *kbuf;
-               struct io_async_ctx io;
-               unsigned flags;
-
-               if (req->io) {
-                       kmsg = &req->io->msg;
-                       kmsg->msg.msg_name = &req->io->msg.addr;
-                       /* if iov is set, it's allocated already */
-                       if (!kmsg->iov)
-                               kmsg->iov = kmsg->fast_iov;
-                       kmsg->msg.msg_iter.iov = kmsg->iov;
-               } else {
-                       kmsg = &io.msg;
-                       kmsg->msg.msg_name = &io.msg.addr;
+       if (unlikely(!sock))
+               return ret;
 
-                       ret = io_recvmsg_copy_hdr(req, &io);
-                       if (ret)
-                               return ret;
-               }
+       if (req->io) {
+               kmsg = &req->io->msg;
+               kmsg->msg.msg_name = &req->io->msg.addr;
+               /* if iov is set, it's allocated already */
+               if (!kmsg->iov)
+                       kmsg->iov = kmsg->fast_iov;
+               kmsg->msg.msg_iter.iov = kmsg->iov;
+       } else {
+               ret = io_recvmsg_copy_hdr(req, &iomsg);
+               if (ret)
+                       return ret;
+               kmsg = &iomsg;
+       }
 
-               kbuf = io_recv_buffer_select(req, &cflags, !force_nonblock);
-               if (IS_ERR(kbuf)) {
+       if (req->flags & REQ_F_BUFFER_SELECT) {
+               kbuf = io_recv_buffer_select(req, !force_nonblock);
+               if (IS_ERR(kbuf))
                        return PTR_ERR(kbuf);
-               } else if (kbuf) {
-                       kmsg->fast_iov[0].iov_base = u64_to_user_ptr(kbuf->addr);
-                       iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->iov,
-                                       1, req->sr_msg.len);
-               }
+               kmsg->fast_iov[0].iov_base = u64_to_user_ptr(kbuf->addr);
+               iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->iov,
+                               1, req->sr_msg.len);
+       }
 
-               flags = req->sr_msg.msg_flags;
-               if (flags & MSG_DONTWAIT)
-                       req->flags |= REQ_F_NOWAIT;
-               else if (force_nonblock)
-                       flags |= MSG_DONTWAIT;
+       flags = req->sr_msg.msg_flags;
+       if (flags & MSG_DONTWAIT)
+               req->flags |= REQ_F_NOWAIT;
+       else if (force_nonblock)
+               flags |= MSG_DONTWAIT;
 
-               ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.msg,
-                                               kmsg->uaddr, flags);
-               if (force_nonblock && ret == -EAGAIN) {
-                       ret = io_setup_async_msg(req, kmsg);
-                       if (ret != -EAGAIN)
-                               kfree(kbuf);
-                       return ret;
-               }
-               if (ret == -ERESTARTSYS)
-                       ret = -EINTR;
-               if (kbuf)
-                       kfree(kbuf);
-       }
+       ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.umsg,
+                                       kmsg->uaddr, flags);
+       if (force_nonblock && ret == -EAGAIN)
+               return io_setup_async_msg(req, kmsg);
+       if (ret == -ERESTARTSYS)
+               ret = -EINTR;
 
-       if (kmsg && kmsg->iov != kmsg->fast_iov)
+       if (req->flags & REQ_F_BUFFER_SELECTED)
+               cflags = io_put_recv_kbuf(req);
+       if (kmsg->iov != kmsg->fast_iov)
                kfree(kmsg->iov);
        req->flags &= ~REQ_F_NEED_CLEANUP;
-       __io_cqring_add_event(req, ret, cflags);
        if (ret < 0)
                req_set_fail_links(req);
-       io_put_req(req);
+       __io_req_complete(req, ret, cflags, cs);
        return 0;
 }
 
-static int io_recv(struct io_kiocb *req, bool force_nonblock)
+static int io_recv(struct io_kiocb *req, bool force_nonblock,
+                  struct io_comp_state *cs)
 {
-       struct io_buffer *kbuf = NULL;
+       struct io_buffer *kbuf;
+       struct io_sr_msg *sr = &req->sr_msg;
+       struct msghdr msg;
+       void __user *buf = sr->buf;
        struct socket *sock;
+       struct iovec iov;
+       unsigned flags;
        int ret, cflags = 0;
 
        sock = sock_from_file(req->file, &ret);
-       if (sock) {
-               struct io_sr_msg *sr = &req->sr_msg;
-               void __user *buf = sr->buf;
-               struct msghdr msg;
-               struct iovec iov;
-               unsigned flags;
+       if (unlikely(!sock))
+               return ret;
 
-               kbuf = io_recv_buffer_select(req, &cflags, !force_nonblock);
+       if (req->flags & REQ_F_BUFFER_SELECT) {
+               kbuf = io_recv_buffer_select(req, !force_nonblock);
                if (IS_ERR(kbuf))
                        return PTR_ERR(kbuf);
-               else if (kbuf)
-                       buf = u64_to_user_ptr(kbuf->addr);
+               buf = u64_to_user_ptr(kbuf->addr);
+       }
 
-               ret = import_single_range(READ, buf, sr->len, &iov,
-                                               &msg.msg_iter);
-               if (ret) {
-                       kfree(kbuf);
-                       return ret;
-               }
+       ret = import_single_range(READ, buf, sr->len, &iov, &msg.msg_iter);
+       if (unlikely(ret))
+               goto out_free;
 
-               req->flags |= REQ_F_NEED_CLEANUP;
-               msg.msg_name = NULL;
-               msg.msg_control = NULL;
-               msg.msg_controllen = 0;
-               msg.msg_namelen = 0;
-               msg.msg_iocb = NULL;
-               msg.msg_flags = 0;
-
-               flags = req->sr_msg.msg_flags;
-               if (flags & MSG_DONTWAIT)
-                       req->flags |= REQ_F_NOWAIT;
-               else if (force_nonblock)
-                       flags |= MSG_DONTWAIT;
-
-               ret = sock_recvmsg(sock, &msg, flags);
-               if (force_nonblock && ret == -EAGAIN)
-                       return -EAGAIN;
-               if (ret == -ERESTARTSYS)
-                       ret = -EINTR;
-       }
+       msg.msg_name = NULL;
+       msg.msg_control = NULL;
+       msg.msg_controllen = 0;
+       msg.msg_namelen = 0;
+       msg.msg_iocb = NULL;
+       msg.msg_flags = 0;
 
-       kfree(kbuf);
-       req->flags &= ~REQ_F_NEED_CLEANUP;
-       __io_cqring_add_event(req, ret, cflags);
+       flags = req->sr_msg.msg_flags;
+       if (flags & MSG_DONTWAIT)
+               req->flags |= REQ_F_NOWAIT;
+       else if (force_nonblock)
+               flags |= MSG_DONTWAIT;
+
+       ret = sock_recvmsg(sock, &msg, flags);
+       if (force_nonblock && ret == -EAGAIN)
+               return -EAGAIN;
+       if (ret == -ERESTARTSYS)
+               ret = -EINTR;
+out_free:
+       if (req->flags & REQ_F_BUFFER_SELECTED)
+               cflags = io_put_recv_kbuf(req);
        if (ret < 0)
                req_set_fail_links(req);
-       io_put_req(req);
+       __io_req_complete(req, ret, cflags, cs);
        return 0;
 }
 
@@ -3941,7 +4410,8 @@ static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
        return 0;
 }
 
-static int io_accept(struct io_kiocb *req, bool force_nonblock)
+static int io_accept(struct io_kiocb *req, bool force_nonblock,
+                    struct io_comp_state *cs)
 {
        struct io_accept *accept = &req->accept;
        unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
@@ -3960,8 +4430,7 @@ static int io_accept(struct io_kiocb *req, bool force_nonblock)
                        ret = -EINTR;
                req_set_fail_links(req);
        }
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       __io_req_complete(req, ret, 0, cs);
        return 0;
 }
 
@@ -3985,7 +4454,8 @@ static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
                                        &io->connect.address);
 }
 
-static int io_connect(struct io_kiocb *req, bool force_nonblock)
+static int io_connect(struct io_kiocb *req, bool force_nonblock,
+                     struct io_comp_state *cs)
 {
        struct io_async_ctx __io, *io;
        unsigned file_flags;
@@ -4021,8 +4491,7 @@ static int io_connect(struct io_kiocb *req, bool force_nonblock)
 out:
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       __io_req_complete(req, ret, 0, cs);
        return 0;
 }
 #else /* !CONFIG_NET */
@@ -4031,12 +4500,14 @@ static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
        return -EOPNOTSUPP;
 }
 
-static int io_sendmsg(struct io_kiocb *req, bool force_nonblock)
+static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
+                     struct io_comp_state *cs)
 {
        return -EOPNOTSUPP;
 }
 
-static int io_send(struct io_kiocb *req, bool force_nonblock)
+static int io_send(struct io_kiocb *req, bool force_nonblock,
+                  struct io_comp_state *cs)
 {
        return -EOPNOTSUPP;
 }
@@ -4047,12 +4518,14 @@ static int io_recvmsg_prep(struct io_kiocb *req,
        return -EOPNOTSUPP;
 }
 
-static int io_recvmsg(struct io_kiocb *req, bool force_nonblock)
+static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
+                     struct io_comp_state *cs)
 {
        return -EOPNOTSUPP;
 }
 
-static int io_recv(struct io_kiocb *req, bool force_nonblock)
+static int io_recv(struct io_kiocb *req, bool force_nonblock,
+                  struct io_comp_state *cs)
 {
        return -EOPNOTSUPP;
 }
@@ -4062,7 +4535,8 @@ static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
        return -EOPNOTSUPP;
 }
 
-static int io_accept(struct io_kiocb *req, bool force_nonblock)
+static int io_accept(struct io_kiocb *req, bool force_nonblock,
+                    struct io_comp_state *cs)
 {
        return -EOPNOTSUPP;
 }
@@ -4072,45 +4546,22 @@ static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
        return -EOPNOTSUPP;
 }
 
-static int io_connect(struct io_kiocb *req, bool force_nonblock)
+static int io_connect(struct io_kiocb *req, bool force_nonblock,
+                     struct io_comp_state *cs)
 {
        return -EOPNOTSUPP;
 }
 #endif /* CONFIG_NET */
 
 struct io_poll_table {
-       struct poll_table_struct pt;
-       struct io_kiocb *req;
-       int error;
-};
-
-static int io_req_task_work_add(struct io_kiocb *req, struct callback_head *cb)
-{
-       struct task_struct *tsk = req->task;
-       struct io_ring_ctx *ctx = req->ctx;
-       int ret, notify = TWA_RESUME;
-
-       /*
-        * SQPOLL kernel thread doesn't need notification, just a wakeup.
-        * If we're not using an eventfd, then TWA_RESUME is always fine,
-        * as we won't have dependencies between request completions for
-        * other kernel wait conditions.
-        */
-       if (ctx->flags & IORING_SETUP_SQPOLL)
-               notify = 0;
-       else if (ctx->cq_ev_fd)
-               notify = TWA_SIGNAL;
-
-       ret = task_work_add(tsk, cb, notify);
-       if (!ret)
-               wake_up_process(tsk);
-       return ret;
-}
+       struct poll_table_struct pt;
+       struct io_kiocb *req;
+       int error;
+};
 
 static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll,
                           __poll_t mask, task_work_func_t func)
 {
-       struct task_struct *tsk;
        int ret;
 
        /* for instances that support it check for an event match first: */
@@ -4121,9 +4572,10 @@ static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll,
 
        list_del_init(&poll->wait.entry);
 
-       tsk = req->task;
        req->result = mask;
        init_task_work(&req->task_work, func);
+       percpu_ref_get(&req->ctx->refs);
+
        /*
         * If this fails, then the task is exiting. When a task exits, the
         * work gets canceled, so just cancel this request as well instead
@@ -4132,6 +4584,8 @@ static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll,
         */
        ret = io_req_task_work_add(req, &req->task_work);
        if (unlikely(ret)) {
+               struct task_struct *tsk;
+
                WRITE_ONCE(poll->canceled, true);
                tsk = io_wq_get_task(req->ctx->io_wq);
                task_work_add(tsk, &req->task_work, 0);
@@ -4199,25 +4653,23 @@ static void io_poll_task_handler(struct io_kiocb *req, struct io_kiocb **nxt)
 
        hash_del(&req->hash_node);
        io_poll_complete(req, req->result, 0);
+       req->flags |= REQ_F_COMP_LOCKED;
+       *nxt = io_put_req_find_next(req);
        spin_unlock_irq(&ctx->completion_lock);
 
-       io_put_req_find_next(req, nxt);
        io_cqring_ev_posted(ctx);
 }
 
 static void io_poll_task_func(struct callback_head *cb)
 {
        struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
+       struct io_ring_ctx *ctx = req->ctx;
        struct io_kiocb *nxt = NULL;
 
        io_poll_task_handler(req, &nxt);
-       if (nxt) {
-               struct io_ring_ctx *ctx = nxt->ctx;
-
-               mutex_lock(&ctx->uring_lock);
-               __io_queue_sqe(nxt, NULL);
-               mutex_unlock(&ctx->uring_lock);
-       }
+       if (nxt)
+               __io_req_task_submit(nxt);
+       percpu_ref_put(&ctx->refs);
 }
 
 static int io_poll_double_wake(struct wait_queue_entry *wait, unsigned mode,
@@ -4287,7 +4739,11 @@ static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt,
 
        pt->error = 0;
        poll->head = head;
-       add_wait_queue(head, &poll->wait);
+
+       if (poll->events & EPOLLEXCLUSIVE)
+               add_wait_queue_exclusive(head, &poll->wait);
+       else
+               add_wait_queue(head, &poll->wait);
 }
 
 static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
@@ -4299,77 +4755,35 @@ static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
        __io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll);
 }
 
-static void io_sq_thread_drop_mm(struct io_ring_ctx *ctx)
-{
-       struct mm_struct *mm = current->mm;
-
-       if (mm) {
-               kthread_unuse_mm(mm);
-               mmput(mm);
-       }
-}
-
-static int io_sq_thread_acquire_mm(struct io_ring_ctx *ctx,
-                                  struct io_kiocb *req)
-{
-       if (io_op_defs[req->opcode].needs_mm && !current->mm) {
-               if (unlikely(!mmget_not_zero(ctx->sqo_mm)))
-                       return -EFAULT;
-               kthread_use_mm(ctx->sqo_mm);
-       }
-
-       return 0;
-}
-
 static void io_async_task_func(struct callback_head *cb)
 {
        struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
        struct async_poll *apoll = req->apoll;
        struct io_ring_ctx *ctx = req->ctx;
-       bool canceled = false;
 
        trace_io_uring_task_run(req->ctx, req->opcode, req->user_data);
 
        if (io_poll_rewait(req, &apoll->poll)) {
                spin_unlock_irq(&ctx->completion_lock);
+               percpu_ref_put(&ctx->refs);
                return;
        }
 
        /* If req is still hashed, it cannot have been canceled. Don't check. */
-       if (hash_hashed(&req->hash_node)) {
+       if (hash_hashed(&req->hash_node))
                hash_del(&req->hash_node);
-       } else {
-               canceled = READ_ONCE(apoll->poll.canceled);
-               if (canceled) {
-                       io_cqring_fill_event(req, -ECANCELED);
-                       io_commit_cqring(ctx);
-               }
-       }
 
        io_poll_remove_double(req, apoll->double_poll);
        spin_unlock_irq(&ctx->completion_lock);
 
-       /* restore ->work in case we need to retry again */
-       if (req->flags & REQ_F_WORK_INITIALIZED)
-               memcpy(&req->work, &apoll->work, sizeof(req->work));
+       if (!READ_ONCE(apoll->poll.canceled))
+               __io_req_task_submit(req);
+       else
+               __io_req_task_cancel(req, -ECANCELED);
+
+       percpu_ref_put(&ctx->refs);
        kfree(apoll->double_poll);
        kfree(apoll);
-
-       if (!canceled) {
-               __set_current_state(TASK_RUNNING);
-               if (io_sq_thread_acquire_mm(ctx, req)) {
-                       io_cqring_add_event(req, -EFAULT);
-                       goto end_req;
-               }
-               mutex_lock(&ctx->uring_lock);
-               __io_queue_sqe(req, NULL);
-               mutex_unlock(&ctx->uring_lock);
-       } else {
-               io_cqring_ev_posted(ctx);
-end_req:
-               req_set_fail_links(req);
-               io_double_put_req(req);
-       }
 }
 
 static int io_async_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
@@ -4402,8 +4816,8 @@ static __poll_t __io_arm_poll_handler(struct io_kiocb *req,
        struct io_ring_ctx *ctx = req->ctx;
        bool cancel = false;
 
-       poll->file = req->file;
        io_init_poll_iocb(poll, mask, wake_func);
+       poll->file = req->file;
        poll->wait.private = req;
 
        ipt->pt._key = mask;
@@ -4443,7 +4857,7 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
 
        if (!req->file || !file_can_poll(req->file))
                return false;
-       if (req->flags & (REQ_F_MUST_PUNT | REQ_F_POLLED))
+       if (req->flags & REQ_F_POLLED)
                return false;
        if (!def->pollin && !def->pollout)
                return false;
@@ -4454,9 +4868,6 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
        apoll->double_poll = NULL;
 
        req->flags |= REQ_F_POLLED;
-       if (req->flags & REQ_F_WORK_INITIALIZED)
-               memcpy(&apoll->work, &req->work, sizeof(req->work));
-
        io_get_req_task(req);
        req->apoll = apoll;
        INIT_HLIST_NODE(&req->hash_node);
@@ -4475,8 +4886,6 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
        if (ret) {
                io_poll_remove_double(req, apoll->double_poll);
                spin_unlock_irq(&ctx->completion_lock);
-               if (req->flags & REQ_F_WORK_INITIALIZED)
-                       memcpy(&req->work, &apoll->work, sizeof(req->work));
                kfree(apoll->double_poll);
                kfree(apoll);
                return false;
@@ -4519,14 +4928,6 @@ static bool io_poll_remove_one(struct io_kiocb *req)
                do_complete = __io_poll_remove_one(req, &apoll->poll);
                if (do_complete) {
                        io_put_req(req);
-                       /*
-                        * restore ->work because we will call
-                        * io_req_work_drop_env below when dropping the
-                        * final reference.
-                        */
-                       if (req->flags & REQ_F_WORK_INITIALIZED)
-                               memcpy(&req->work, &apoll->work,
-                                      sizeof(req->work));
                        kfree(apoll->double_poll);
                        kfree(apoll);
                }
@@ -4607,10 +5008,9 @@ static int io_poll_remove(struct io_kiocb *req)
        ret = io_poll_cancel(ctx, addr);
        spin_unlock_irq(&ctx->completion_lock);
 
-       io_cqring_add_event(req, ret);
        if (ret < 0)
                req_set_fail_links(req);
-       io_put_req(req);
+       io_req_complete(req, ret);
        return 0;
 }
 
@@ -4634,7 +5034,7 @@ static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
 static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
        struct io_poll_iocb *poll = &req->poll;
-       u16 events;
+       u32 events;
 
        if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
                return -EINVAL;
@@ -4643,8 +5043,12 @@ static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe
        if (!poll->file)
                return -EBADF;
 
-       events = READ_ONCE(sqe->poll_events);
-       poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;
+       events = READ_ONCE(sqe->poll32_events);
+#ifdef __BIG_ENDIAN
+       events = swahw32(events);
+#endif
+       poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP |
+                      (events & EPOLLEXCLUSIVE);
 
        io_get_req_task(req);
        return 0;
@@ -4657,12 +5061,7 @@ static int io_poll_add(struct io_kiocb *req)
        struct io_poll_table ipt;
        __poll_t mask;
 
-       /* ->work is in union with hash_node and others */
-       io_req_work_drop_env(req);
-       req->flags &= ~REQ_F_WORK_INITIALIZED;
-
        INIT_HLIST_NODE(&req->hash_node);
-       INIT_LIST_HEAD(&req->list);
        ipt.pt._qproc = io_poll_queue_proc;
 
        mask = __io_arm_poll_handler(req, &req->poll, &ipt, poll->events,
@@ -4689,15 +5088,16 @@ static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
        struct io_ring_ctx *ctx = req->ctx;
        unsigned long flags;
 
-       atomic_inc(&ctx->cq_timeouts);
-
        spin_lock_irqsave(&ctx->completion_lock, flags);
+       atomic_set(&req->ctx->cq_timeouts,
+               atomic_read(&req->ctx->cq_timeouts) + 1);
+
        /*
         * We could be racing with timeout deletion. If the list is empty,
         * then timeout lookup already found it and will be handling it.
         */
-       if (!list_empty(&req->list))
-               list_del_init(&req->list);
+       if (!list_empty(&req->timeout.list))
+               list_del_init(&req->timeout.list);
 
        io_cqring_fill_event(req, -ETIME);
        io_commit_cqring(ctx);
@@ -4714,9 +5114,9 @@ static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
        struct io_kiocb *req;
        int ret = -ENOENT;
 
-       list_for_each_entry(req, &ctx->timeout_list, list) {
+       list_for_each_entry(req, &ctx->timeout_list, timeout.list) {
                if (user_data == req->user_data) {
-                       list_del_init(&req->list);
+                       list_del_init(&req->timeout.list);
                        ret = 0;
                        break;
                }
@@ -4730,6 +5130,7 @@ static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
                return -EALREADY;
 
        req_set_fail_links(req);
+       req->flags |= REQ_F_COMP_LOCKED;
        io_cqring_fill_event(req, -ECANCELED);
        io_put_req(req);
        return 0;
@@ -4798,7 +5199,6 @@ static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 
        data = &req->io->timeout;
        data->req = req;
-       req->flags |= REQ_F_TIMEOUT;
 
        if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
                return -EFAULT;
@@ -4826,8 +5226,7 @@ static int io_timeout(struct io_kiocb *req)
         * timeout event to be satisfied. If it isn't set, then this is
         * a pure timeout request, sequence isn't used.
         */
-       if (!off) {
-               req->flags |= REQ_F_TIMEOUT_NOSEQ;
+       if (io_is_timeout_noseq(req)) {
                entry = ctx->timeout_list.prev;
                goto add;
        }
@@ -4840,16 +5239,17 @@ static int io_timeout(struct io_kiocb *req)
         * the one we need first.
         */
        list_for_each_prev(entry, &ctx->timeout_list) {
-               struct io_kiocb *nxt = list_entry(entry, struct io_kiocb, list);
+               struct io_kiocb *nxt = list_entry(entry, struct io_kiocb,
+                                                 timeout.list);
 
-               if (nxt->flags & REQ_F_TIMEOUT_NOSEQ)
+               if (io_is_timeout_noseq(nxt))
                        continue;
                /* nxt.seq is behind @tail, otherwise would've been completed */
                if (off >= nxt->timeout.target_seq - tail)
                        break;
        }
 add:
-       list_add(&req->list, entry);
+       list_add(&req->timeout.list, entry);
        data->timer.function = io_timeout_fn;
        hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
        spin_unlock_irq(&ctx->completion_lock);
@@ -4953,7 +5353,8 @@ static int io_files_update_prep(struct io_kiocb *req,
        return 0;
 }
 
-static int io_files_update(struct io_kiocb *req, bool force_nonblock)
+static int io_files_update(struct io_kiocb *req, bool force_nonblock,
+                          struct io_comp_state *cs)
 {
        struct io_ring_ctx *ctx = req->ctx;
        struct io_uring_files_update up;
@@ -4971,8 +5372,7 @@ static int io_files_update(struct io_kiocb *req, bool force_nonblock)
 
        if (ret < 0)
                req_set_fail_links(req);
-       io_cqring_add_event(req, ret);
-       io_put_req(req);
+       __io_req_complete(req, ret, 0, cs);
        return 0;
 }
 
@@ -4984,15 +5384,11 @@ static int io_req_defer_prep(struct io_kiocb *req,
        if (!sqe)
                return 0;
 
-       io_req_init_async(req);
-
-       if (io_op_defs[req->opcode].file_table) {
-               ret = io_grab_files(req);
-               if (unlikely(ret))
-                       return ret;
-       }
-
-       io_req_work_grab_env(req, &io_op_defs[req->opcode]);
+       if (io_alloc_async_ctx(req))
+               return -EAGAIN;
+       ret = io_prep_work_files(req);
+       if (unlikely(ret))
+               return ret;
 
        switch (req->opcode) {
        case IORING_OP_NOP:
@@ -5094,86 +5490,117 @@ static int io_req_defer_prep(struct io_kiocb *req,
        return ret;
 }
 
+static u32 io_get_sequence(struct io_kiocb *req)
+{
+       struct io_kiocb *pos;
+       struct io_ring_ctx *ctx = req->ctx;
+       u32 total_submitted, nr_reqs = 1;
+
+       if (req->flags & REQ_F_LINK_HEAD)
+               list_for_each_entry(pos, &req->link_list, link_list)
+                       nr_reqs++;
+
+       total_submitted = ctx->cached_sq_head - ctx->cached_sq_dropped;
+       return total_submitted - nr_reqs;
+}
+
 static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
        struct io_ring_ctx *ctx = req->ctx;
+       struct io_defer_entry *de;
        int ret;
+       u32 seq;
 
        /* Still need defer if there is pending req in defer list. */
-       if (!req_need_defer(req) && list_empty_careful(&ctx->defer_list))
+       if (likely(list_empty_careful(&ctx->defer_list) &&
+               !(req->flags & REQ_F_IO_DRAIN)))
+               return 0;
+
+       seq = io_get_sequence(req);
+       /* Still a chance to pass the sequence check */
+       if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list))
                return 0;
 
        if (!req->io) {
-               if (io_alloc_async_ctx(req))
-                       return -EAGAIN;
                ret = io_req_defer_prep(req, sqe);
-               if (ret < 0)
+               if (ret)
                        return ret;
        }
+       io_prep_async_link(req);
+       de = kmalloc(sizeof(*de), GFP_KERNEL);
+       if (!de)
+               return -ENOMEM;
 
        spin_lock_irq(&ctx->completion_lock);
-       if (!req_need_defer(req) && list_empty(&ctx->defer_list)) {
+       if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {
                spin_unlock_irq(&ctx->completion_lock);
-               return 0;
+               kfree(de);
+               io_queue_async_work(req);
+               return -EIOCBQUEUED;
        }
 
        trace_io_uring_defer(ctx, req, req->user_data);
-       list_add_tail(&req->list, &ctx->defer_list);
+       de->req = req;
+       de->seq = seq;
+       list_add_tail(&de->list, &ctx->defer_list);
        spin_unlock_irq(&ctx->completion_lock);
        return -EIOCBQUEUED;
 }
 
-static void io_cleanup_req(struct io_kiocb *req)
+static void __io_clean_op(struct io_kiocb *req)
 {
        struct io_async_ctx *io = req->io;
 
-       switch (req->opcode) {
-       case IORING_OP_READV:
-       case IORING_OP_READ_FIXED:
-       case IORING_OP_READ:
-               if (req->flags & REQ_F_BUFFER_SELECTED)
+       if (req->flags & REQ_F_BUFFER_SELECTED) {
+               switch (req->opcode) {
+               case IORING_OP_READV:
+               case IORING_OP_READ_FIXED:
+               case IORING_OP_READ:
                        kfree((void *)(unsigned long)req->rw.addr);
-               /* fallthrough */
-       case IORING_OP_WRITEV:
-       case IORING_OP_WRITE_FIXED:
-       case IORING_OP_WRITE:
-               if (io->rw.iov != io->rw.fast_iov)
-                       kfree(io->rw.iov);
-               break;
-       case IORING_OP_RECVMSG:
-               if (req->flags & REQ_F_BUFFER_SELECTED)
-                       kfree(req->sr_msg.kbuf);
-               /* fallthrough */
-       case IORING_OP_SENDMSG:
-               if (io->msg.iov != io->msg.fast_iov)
-                       kfree(io->msg.iov);
-               break;
-       case IORING_OP_RECV:
-               if (req->flags & REQ_F_BUFFER_SELECTED)
+                       break;
+               case IORING_OP_RECVMSG:
+               case IORING_OP_RECV:
                        kfree(req->sr_msg.kbuf);
-               break;
-       case IORING_OP_OPENAT:
-       case IORING_OP_OPENAT2:
-               break;
-       case IORING_OP_SPLICE:
-       case IORING_OP_TEE:
-               io_put_file(req, req->splice.file_in,
-                           (req->splice.flags & SPLICE_F_FD_IN_FIXED));
-               break;
+                       break;
+               }
+               req->flags &= ~REQ_F_BUFFER_SELECTED;
+       }
+
+       if (req->flags & REQ_F_NEED_CLEANUP) {
+               switch (req->opcode) {
+               case IORING_OP_READV:
+               case IORING_OP_READ_FIXED:
+               case IORING_OP_READ:
+               case IORING_OP_WRITEV:
+               case IORING_OP_WRITE_FIXED:
+               case IORING_OP_WRITE:
+                       if (io->rw.iov != io->rw.fast_iov)
+                               kfree(io->rw.iov);
+                       break;
+               case IORING_OP_RECVMSG:
+               case IORING_OP_SENDMSG:
+                       if (io->msg.iov != io->msg.fast_iov)
+                               kfree(io->msg.iov);
+                       break;
+               case IORING_OP_SPLICE:
+               case IORING_OP_TEE:
+                       io_put_file(req, req->splice.file_in,
+                                   (req->splice.flags & SPLICE_F_FD_IN_FIXED));
+                       break;
+               }
+               req->flags &= ~REQ_F_NEED_CLEANUP;
        }
-
-       req->flags &= ~REQ_F_NEED_CLEANUP;
 }
 
 static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
-                       bool force_nonblock)
+                       bool force_nonblock, struct io_comp_state *cs)
 {
        struct io_ring_ctx *ctx = req->ctx;
        int ret;
 
        switch (req->opcode) {
        case IORING_OP_NOP:
-               ret = io_nop(req);
+               ret = io_nop(req, cs);
                break;
        case IORING_OP_READV:
        case IORING_OP_READ_FIXED:
@@ -5183,7 +5610,7 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                        if (ret < 0)
                                break;
                }
-               ret = io_read(req, force_nonblock);
+               ret = io_read(req, force_nonblock, cs);
                break;
        case IORING_OP_WRITEV:
        case IORING_OP_WRITE_FIXED:
@@ -5193,7 +5620,7 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                        if (ret < 0)
                                break;
                }
-               ret = io_write(req, force_nonblock);
+               ret = io_write(req, force_nonblock, cs);
                break;
        case IORING_OP_FSYNC:
                if (sqe) {
@@ -5235,9 +5662,9 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                                break;
                }
                if (req->opcode == IORING_OP_SENDMSG)
-                       ret = io_sendmsg(req, force_nonblock);
+                       ret = io_sendmsg(req, force_nonblock, cs);
                else
-                       ret = io_send(req, force_nonblock);
+                       ret = io_send(req, force_nonblock, cs);
                break;
        case IORING_OP_RECVMSG:
        case IORING_OP_RECV:
@@ -5247,9 +5674,9 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                                break;
                }
                if (req->opcode == IORING_OP_RECVMSG)
-                       ret = io_recvmsg(req, force_nonblock);
+                       ret = io_recvmsg(req, force_nonblock, cs);
                else
-                       ret = io_recv(req, force_nonblock);
+                       ret = io_recv(req, force_nonblock, cs);
                break;
        case IORING_OP_TIMEOUT:
                if (sqe) {
@@ -5273,7 +5700,7 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                        if (ret)
                                break;
                }
-               ret = io_accept(req, force_nonblock);
+               ret = io_accept(req, force_nonblock, cs);
                break;
        case IORING_OP_CONNECT:
                if (sqe) {
@@ -5281,7 +5708,7 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                        if (ret)
                                break;
                }
-               ret = io_connect(req, force_nonblock);
+               ret = io_connect(req, force_nonblock, cs);
                break;
        case IORING_OP_ASYNC_CANCEL:
                if (sqe) {
@@ -5313,7 +5740,7 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                        if (ret)
                                break;
                }
-               ret = io_close(req, force_nonblock);
+               ret = io_close(req, force_nonblock, cs);
                break;
        case IORING_OP_FILES_UPDATE:
                if (sqe) {
@@ -5321,7 +5748,7 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                        if (ret)
                                break;
                }
-               ret = io_files_update(req, force_nonblock);
+               ret = io_files_update(req, force_nonblock, cs);
                break;
        case IORING_OP_STATX:
                if (sqe) {
@@ -5361,7 +5788,7 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                        if (ret)
                                break;
                }
-               ret = io_epoll_ctl(req, force_nonblock);
+               ret = io_epoll_ctl(req, force_nonblock, cs);
                break;
        case IORING_OP_SPLICE:
                if (sqe) {
@@ -5377,7 +5804,7 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                        if (ret)
                                break;
                }
-               ret = io_provide_buffers(req, force_nonblock);
+               ret = io_provide_buffers(req, force_nonblock, cs);
                break;
        case IORING_OP_REMOVE_BUFFERS:
                if (sqe) {
@@ -5385,7 +5812,7 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                        if (ret)
                                break;
                }
-               ret = io_remove_buffers(req, force_nonblock);
+               ret = io_remove_buffers(req, force_nonblock, cs);
                break;
        case IORING_OP_TEE:
                if (sqe) {
@@ -5420,25 +5847,15 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
        return 0;
 }
 
-static void io_arm_async_linked_timeout(struct io_kiocb *req)
-{
-       struct io_kiocb *link;
-
-       /* link head's timeout is queued in io_queue_async_work() */
-       if (!(req->flags & REQ_F_QUEUE_TIMEOUT))
-               return;
-
-       link = list_first_entry(&req->link_list, struct io_kiocb, link_list);
-       io_queue_linked_timeout(link);
-}
-
-static void io_wq_submit_work(struct io_wq_work **workptr)
+static struct io_wq_work *io_wq_submit_work(struct io_wq_work *work)
 {
-       struct io_wq_work *work = *workptr;
        struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+       struct io_kiocb *timeout;
        int ret = 0;
 
-       io_arm_async_linked_timeout(req);
+       timeout = io_prep_linked_timeout(req);
+       if (timeout)
+               io_queue_linked_timeout(timeout);
 
        /* if NO_CANCEL is set, we must still run the work */
        if ((work->flags & (IO_WQ_WORK_CANCEL|IO_WQ_WORK_NO_CANCEL)) ==
@@ -5448,7 +5865,7 @@ static void io_wq_submit_work(struct io_wq_work **workptr)
 
        if (!ret) {
                do {
-                       ret = io_issue_sqe(req, NULL, false);
+                       ret = io_issue_sqe(req, NULL, false, NULL);
                        /*
                         * We can get EAGAIN for polled IO even though we're
                         * forcing a sync submission from here, since we can't
@@ -5462,11 +5879,10 @@ static void io_wq_submit_work(struct io_wq_work **workptr)
 
        if (ret) {
                req_set_fail_links(req);
-               io_cqring_add_event(req, ret);
-               io_put_req(req);
+               io_req_complete(req, ret);
        }
 
-       io_steal_work(req, workptr);
+       return io_steal_work(req);
 }
 
 static inline struct file *io_file_from_index(struct io_ring_ctx *ctx,
@@ -5523,6 +5939,8 @@ static int io_grab_files(struct io_kiocb *req)
        int ret = -EBADF;
        struct io_ring_ctx *ctx = req->ctx;
 
+       io_req_init_async(req);
+
        if (req->work.files || (req->flags & REQ_F_NO_FILE_TABLE))
                return 0;
        if (!ctx->ring_file)
@@ -5548,6 +5966,13 @@ static int io_grab_files(struct io_kiocb *req)
        return ret;
 }
 
+static inline int io_prep_work_files(struct io_kiocb *req)
+{
+       if (!io_op_defs[req->opcode].file_table)
+               return 0;
+       return io_grab_files(req);
+}
+
 static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
 {
        struct io_timeout_data *data = container_of(timer,
@@ -5580,21 +6005,17 @@ static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
                io_async_find_and_cancel(ctx, req, prev->user_data, -ETIME);
                io_put_req(prev);
        } else {
-               io_cqring_add_event(req, -ETIME);
-               io_put_req(req);
+               io_req_complete(req, -ETIME);
        }
        return HRTIMER_NORESTART;
 }
 
-static void io_queue_linked_timeout(struct io_kiocb *req)
+static void __io_queue_linked_timeout(struct io_kiocb *req)
 {
-       struct io_ring_ctx *ctx = req->ctx;
-
        /*
         * If the list is now empty, then our linked request finished before
         * we got a chance to setup the timer
         */
-       spin_lock_irq(&ctx->completion_lock);
        if (!list_empty(&req->link_list)) {
                struct io_timeout_data *data = &req->io->timeout;
 
@@ -5602,6 +6023,14 @@ static void io_queue_linked_timeout(struct io_kiocb *req)
                hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
                                data->mode);
        }
+}
+
+static void io_queue_linked_timeout(struct io_kiocb *req)
+{
+       struct io_ring_ctx *ctx = req->ctx;
+
+       spin_lock_irq(&ctx->completion_lock);
+       __io_queue_linked_timeout(req);
        spin_unlock_irq(&ctx->completion_lock);
 
        /* drop submission reference */
@@ -5614,8 +6043,7 @@ static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
 
        if (!(req->flags & REQ_F_LINK_HEAD))
                return NULL;
-       /* for polled retry, if flag is set, we already went through here */
-       if (req->flags & REQ_F_POLLED)
+       if (req->flags & REQ_F_LINK_TIMEOUT)
                return NULL;
 
        nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb,
@@ -5627,7 +6055,8 @@ static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
        return nxt;
 }
 
-static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
+                          struct io_comp_state *cs)
 {
        struct io_kiocb *linked_timeout;
        struct io_kiocb *nxt;
@@ -5647,54 +6076,45 @@ again:
                        old_creds = override_creds(req->work.creds);
        }
 
-       ret = io_issue_sqe(req, sqe, true);
+       ret = io_issue_sqe(req, sqe, true, cs);
 
        /*
         * We async punt it if the file wasn't marked NOWAIT, or if the file
         * doesn't support non-blocking read/write attempts
         */
-       if (ret == -EAGAIN && (!(req->flags & REQ_F_NOWAIT) ||
-           (req->flags & REQ_F_MUST_PUNT))) {
-               if (io_arm_poll_handler(req)) {
-                       if (linked_timeout)
-                               io_queue_linked_timeout(linked_timeout);
-                       goto exit;
-               }
+       if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) {
+               if (!io_arm_poll_handler(req)) {
 punt:
-               io_req_init_async(req);
-
-               if (io_op_defs[req->opcode].file_table) {
-                       ret = io_grab_files(req);
-                       if (ret)
+                       ret = io_prep_work_files(req);
+                       if (unlikely(ret))
                                goto err;
+                       /*
+                        * Queued up for async execution, worker will release
+                        * submit reference when the iocb is actually submitted.
+                        */
+                       io_queue_async_work(req);
                }
 
-               /*
-                * Queued up for async execution, worker will release
-                * submit reference when the iocb is actually submitted.
-                */
-               io_queue_async_work(req);
+               if (linked_timeout)
+                       io_queue_linked_timeout(linked_timeout);
                goto exit;
        }
 
+       if (unlikely(ret)) {
 err:
-       nxt = NULL;
-       /* drop submission reference */
-       io_put_req_find_next(req, &nxt);
-
-       if (linked_timeout) {
-               if (!ret)
-                       io_queue_linked_timeout(linked_timeout);
-               else
-                       io_put_req(linked_timeout);
-       }
-
-       /* and drop final reference, if we failed */
-       if (ret) {
-               io_cqring_add_event(req, ret);
+               /* un-prep timeout, so it'll be killed as any other linked */
+               req->flags &= ~REQ_F_LINK_TIMEOUT;
                req_set_fail_links(req);
                io_put_req(req);
+               io_req_complete(req, ret);
+               goto exit;
        }
+
+       /* drop submission reference */
+       nxt = io_put_req_find_next(req);
+       if (linked_timeout)
+               io_queue_linked_timeout(linked_timeout);
+
        if (nxt) {
                req = nxt;
 
@@ -5707,7 +6127,8 @@ exit:
                revert_creds(old_creds);
 }
 
-static void io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+static void io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
+                        struct io_comp_state *cs)
 {
        int ret;
 
@@ -5715,17 +6136,14 @@ static void io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe)
        if (ret) {
                if (ret != -EIOCBQUEUED) {
 fail_req:
-                       io_cqring_add_event(req, ret);
                        req_set_fail_links(req);
-                       io_double_put_req(req);
+                       io_put_req(req);
+                       io_req_complete(req, ret);
                }
        } else if (req->flags & REQ_F_FORCE_ASYNC) {
                if (!req->io) {
-                       ret = -EAGAIN;
-                       if (io_alloc_async_ctx(req))
-                               goto fail_req;
                        ret = io_req_defer_prep(req, sqe);
-                       if (unlikely(ret < 0))
+                       if (unlikely(ret))
                                goto fail_req;
                }
 
@@ -5737,21 +6155,22 @@ fail_req:
                req->work.flags |= IO_WQ_WORK_CONCURRENT;
                io_queue_async_work(req);
        } else {
-               __io_queue_sqe(req, sqe);
+               __io_queue_sqe(req, sqe, cs);
        }
 }
 
-static inline void io_queue_link_head(struct io_kiocb *req)
+static inline void io_queue_link_head(struct io_kiocb *req,
+                                     struct io_comp_state *cs)
 {
        if (unlikely(req->flags & REQ_F_FAIL_LINK)) {
-               io_cqring_add_event(req, -ECANCELED);
-               io_double_put_req(req);
+               io_put_req(req);
+               io_req_complete(req, -ECANCELED);
        } else
-               io_queue_sqe(req, NULL);
+               io_queue_sqe(req, NULL, cs);
 }
 
 static int io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
-                        struct io_kiocb **link)
+                        struct io_kiocb **link, struct io_comp_state *cs)
 {
        struct io_ring_ctx *ctx = req->ctx;
        int ret;
@@ -5777,21 +6196,19 @@ static int io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                        head->flags |= REQ_F_IO_DRAIN;
                        ctx->drain_next = 1;
                }
-               if (io_alloc_async_ctx(req))
-                       return -EAGAIN;
-
                ret = io_req_defer_prep(req, sqe);
-               if (ret) {
+               if (unlikely(ret)) {
                        /* fail even hard links since we don't submit */
                        head->flags |= REQ_F_FAIL_LINK;
                        return ret;
                }
                trace_io_uring_link(ctx, req, head);
+               io_get_req_task(req);
                list_add_tail(&req->link_list, &head->link_list);
 
                /* last request of a link, enqueue the link */
                if (!(req->flags & (REQ_F_LINK | REQ_F_HARDLINK))) {
-                       io_queue_link_head(head);
+                       io_queue_link_head(head, cs);
                        *link = NULL;
                }
        } else {
@@ -5803,15 +6220,12 @@ static int io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
                        req->flags |= REQ_F_LINK_HEAD;
                        INIT_LIST_HEAD(&req->link_list);
 
-                       if (io_alloc_async_ctx(req))
-                               return -EAGAIN;
-
                        ret = io_req_defer_prep(req, sqe);
-                       if (ret)
+                       if (unlikely(ret))
                                req->flags |= REQ_F_FAIL_LINK;
                        *link = req;
                } else {
-                       io_queue_sqe(req, sqe);
+                       io_queue_sqe(req, sqe, cs);
                }
        }
 
@@ -5823,6 +6237,8 @@ static int io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
  */
 static void io_submit_state_end(struct io_submit_state *state)
 {
+       if (!list_empty(&state->comp.list))
+               io_submit_flush_completions(&state->comp);
        blk_finish_plug(&state->plug);
        io_state_file_put(state);
        if (state->free_reqs)
@@ -5833,9 +6249,15 @@ static void io_submit_state_end(struct io_submit_state *state)
  * Start submission side cache.
  */
 static void io_submit_state_start(struct io_submit_state *state,
-                                 unsigned int max_ios)
+                                 struct io_ring_ctx *ctx, unsigned int max_ios)
 {
        blk_start_plug(&state->plug);
+#ifdef CONFIG_BLOCK
+       state->plug.nowait = true;
+#endif
+       state->comp.nr = 0;
+       INIT_LIST_HEAD(&state->comp.list);
+       state->comp.ctx = ctx;
        state->free_reqs = 0;
        state->file = NULL;
        state->ios_left = max_ios;
@@ -5900,12 +6322,6 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
        unsigned int sqe_flags;
        int id;
 
-       /*
-        * All io need record the previous position, if LINK vs DARIN,
-        * it can be used to mark the position of the first IO in the
-        * link list.
-        */
-       req->sequence = ctx->cached_sq_head - ctx->cached_sq_dropped;
        req->opcode = READ_ONCE(sqe->opcode);
        req->user_data = READ_ONCE(sqe->user_data);
        req->io = NULL;
@@ -5953,7 +6369,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
 static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
                          struct file *ring_file, int ring_fd)
 {
-       struct io_submit_state state, *statep = NULL;
+       struct io_submit_state state;
        struct io_kiocb *link = NULL;
        int i, submitted = 0;
 
@@ -5970,10 +6386,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
        if (!percpu_ref_tryget_many(&ctx->refs, nr))
                return -EAGAIN;
 
-       if (nr > IO_PLUG_THRESHOLD) {
-               io_submit_state_start(&state, nr);
-               statep = &state;
-       }
+       io_submit_state_start(&state, ctx, nr);
 
        ctx->ring_fd = ring_fd;
        ctx->ring_file = ring_file;
@@ -5988,28 +6401,28 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
                        io_consume_sqe(ctx);
                        break;
                }
-               req = io_alloc_req(ctx, statep);
+               req = io_alloc_req(ctx, &state);
                if (unlikely(!req)) {
                        if (!submitted)
                                submitted = -EAGAIN;
                        break;
                }
 
-               err = io_init_req(ctx, req, sqe, statep);
+               err = io_init_req(ctx, req, sqe, &state);
                io_consume_sqe(ctx);
                /* will complete beyond this point, count as submitted */
                submitted++;
 
                if (unlikely(err)) {
 fail_req:
-                       io_cqring_add_event(req, err);
-                       io_double_put_req(req);
+                       io_put_req(req);
+                       io_req_complete(req, err);
                        break;
                }
 
                trace_io_uring_submit_sqe(ctx, req->opcode, req->user_data,
                                                true, io_async_submit(ctx));
-               err = io_submit_sqe(req, sqe, &link);
+               err = io_submit_sqe(req, sqe, &link, &state.comp);
                if (err)
                        goto fail_req;
        }
@@ -6020,9 +6433,8 @@ fail_req:
                percpu_ref_put_many(&ctx->refs, nr - ref_used);
        }
        if (link)
-               io_queue_link_head(link);
-       if (statep)
-               io_submit_state_end(&state);
+               io_queue_link_head(link, &state.comp);
+       io_submit_state_end(&state);
 
         /* Commit SQ ring head once we've consumed and submitted all SQEs */
        io_commit_sqring(ctx);
@@ -6030,6 +6442,21 @@ fail_req:
        return submitted;
 }
 
+static inline void io_ring_set_wakeup_flag(struct io_ring_ctx *ctx)
+{
+       /* Tell userspace we may need a wakeup call */
+       spin_lock_irq(&ctx->completion_lock);
+       ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
+       spin_unlock_irq(&ctx->completion_lock);
+}
+
+static inline void io_ring_clear_wakeup_flag(struct io_ring_ctx *ctx)
+{
+       spin_lock_irq(&ctx->completion_lock);
+       ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
+       spin_unlock_irq(&ctx->completion_lock);
+}
+
 static int io_sq_thread(void *data)
 {
        struct io_ring_ctx *ctx = data;
@@ -6046,12 +6473,12 @@ static int io_sq_thread(void *data)
        while (!kthread_should_park()) {
                unsigned int to_submit;
 
-               if (!list_empty(&ctx->poll_list)) {
+               if (!list_empty(&ctx->iopoll_list)) {
                        unsigned nr_events = 0;
 
                        mutex_lock(&ctx->uring_lock);
-                       if (!list_empty(&ctx->poll_list))
-                               io_iopoll_getevents(ctx, &nr_events, 0);
+                       if (!list_empty(&ctx->iopoll_list) && !need_resched())
+                               io_do_iopoll(ctx, &nr_events, 0);
                        else
                                timeout = jiffies + ctx->sq_thread_idle;
                        mutex_unlock(&ctx->uring_lock);
@@ -6070,7 +6497,7 @@ static int io_sq_thread(void *data)
                         * adding ourselves to the waitqueue, as the unuse/drop
                         * may sleep.
                         */
-                       io_sq_thread_drop_mm(ctx);
+                       io_sq_thread_drop_mm();
 
                        /*
                         * We're polling. If we're within the defined idle
@@ -6079,11 +6506,10 @@ static int io_sq_thread(void *data)
                         * more IO, we should wait for the application to
                         * reap events and wake us up.
                         */
-                       if (!list_empty(&ctx->poll_list) || need_resched() ||
+                       if (!list_empty(&ctx->iopoll_list) || need_resched() ||
                            (!time_after(jiffies, timeout) && ret != -EBUSY &&
                            !percpu_ref_is_dying(&ctx->refs))) {
-                               if (current->task_works)
-                                       task_work_run();
+                               io_run_task_work();
                                cond_resched();
                                continue;
                        }
@@ -6093,21 +6519,18 @@ static int io_sq_thread(void *data)
 
                        /*
                         * While doing polled IO, before going to sleep, we need
-                        * to check if there are new reqs added to poll_list, it
-                        * is because reqs may have been punted to io worker and
-                        * will be added to poll_list later, hence check the
-                        * poll_list again.
+                        * to check if there are new reqs added to iopoll_list,
+                        * it is because reqs may have been punted to io worker
+                        * and will be added to iopoll_list later, hence check
+                        * the iopoll_list again.
                         */
                        if ((ctx->flags & IORING_SETUP_IOPOLL) &&
-                           !list_empty_careful(&ctx->poll_list)) {
+                           !list_empty_careful(&ctx->iopoll_list)) {
                                finish_wait(&ctx->sqo_wait, &wait);
                                continue;
                        }
 
-                       /* Tell userspace we may need a wakeup call */
-                       spin_lock_irq(&ctx->completion_lock);
-                       ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
-                       spin_unlock_irq(&ctx->completion_lock);
+                       io_ring_set_wakeup_flag(ctx);
 
                        to_submit = io_sqring_entries(ctx);
                        if (!to_submit || ret == -EBUSY) {
@@ -6115,9 +6538,9 @@ static int io_sq_thread(void *data)
                                        finish_wait(&ctx->sqo_wait, &wait);
                                        break;
                                }
-                               if (current->task_works) {
-                                       task_work_run();
+                               if (io_run_task_work()) {
                                        finish_wait(&ctx->sqo_wait, &wait);
+                                       io_ring_clear_wakeup_flag(ctx);
                                        continue;
                                }
                                if (signal_pending(current))
@@ -6125,17 +6548,13 @@ static int io_sq_thread(void *data)
                                schedule();
                                finish_wait(&ctx->sqo_wait, &wait);
 
-                               spin_lock_irq(&ctx->completion_lock);
-                               ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
-                               spin_unlock_irq(&ctx->completion_lock);
+                               io_ring_clear_wakeup_flag(ctx);
                                ret = 0;
                                continue;
                        }
                        finish_wait(&ctx->sqo_wait, &wait);
 
-                       spin_lock_irq(&ctx->completion_lock);
-                       ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
-                       spin_unlock_irq(&ctx->completion_lock);
+                       io_ring_clear_wakeup_flag(ctx);
                }
 
                mutex_lock(&ctx->uring_lock);
@@ -6145,10 +6564,9 @@ static int io_sq_thread(void *data)
                timeout = jiffies + ctx->sq_thread_idle;
        }
 
-       if (current->task_works)
-               task_work_run();
+       io_run_task_work();
 
-       io_sq_thread_drop_mm(ctx);
+       io_sq_thread_drop_mm();
        revert_creds(old_cred);
 
        kthread_parkme();
@@ -6211,9 +6629,8 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
        do {
                if (io_cqring_events(ctx, false) >= min_events)
                        return 0;
-               if (!current->task_works)
+               if (!io_run_task_work())
                        break;
-               task_work_run();
        } while (1);
 
        if (sig) {
@@ -6235,8 +6652,8 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
                prepare_to_wait_exclusive(&ctx->wait, &iowq.wq,
                                                TASK_INTERRUPTIBLE);
                /* make sure we run task_work before checking for signals */
-               if (current->task_works)
-                       task_work_run();
+               if (io_run_task_work())
+                       continue;
                if (signal_pending(current)) {
                        if (current->jobctl & JOBCTL_TASK_WORK) {
                                spin_lock_irq(&current->sighand->siglock);
@@ -7022,17 +7439,21 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
        return 0;
 err:
        io_finish_async(ctx);
-       mmdrop(ctx->sqo_mm);
-       ctx->sqo_mm = NULL;
+       if (ctx->sqo_mm) {
+               mmdrop(ctx->sqo_mm);
+               ctx->sqo_mm = NULL;
+       }
        return ret;
 }
 
-static void io_unaccount_mem(struct user_struct *user, unsigned long nr_pages)
+static inline void __io_unaccount_mem(struct user_struct *user,
+                                     unsigned long nr_pages)
 {
        atomic_long_sub(nr_pages, &user->locked_vm);
 }
 
-static int io_account_mem(struct user_struct *user, unsigned long nr_pages)
+static inline int __io_account_mem(struct user_struct *user,
+                                  unsigned long nr_pages)
 {
        unsigned long page_limit, cur_pages, new_pages;
 
@@ -7050,6 +7471,41 @@ static int io_account_mem(struct user_struct *user, unsigned long nr_pages)
        return 0;
 }
 
+static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages,
+                            enum io_mem_account acct)
+{
+       if (ctx->limit_mem)
+               __io_unaccount_mem(ctx->user, nr_pages);
+
+       if (ctx->sqo_mm) {
+               if (acct == ACCT_LOCKED)
+                       ctx->sqo_mm->locked_vm -= nr_pages;
+               else if (acct == ACCT_PINNED)
+                       atomic64_sub(nr_pages, &ctx->sqo_mm->pinned_vm);
+       }
+}
+
+static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages,
+                         enum io_mem_account acct)
+{
+       int ret;
+
+       if (ctx->limit_mem) {
+               ret = __io_account_mem(ctx->user, nr_pages);
+               if (ret)
+                       return ret;
+       }
+
+       if (ctx->sqo_mm) {
+               if (acct == ACCT_LOCKED)
+                       ctx->sqo_mm->locked_vm += nr_pages;
+               else if (acct == ACCT_PINNED)
+                       atomic64_add(nr_pages, &ctx->sqo_mm->pinned_vm);
+       }
+
+       return 0;
+}
+
 static void io_mem_free(void *ptr)
 {
        struct page *page;
@@ -7086,6 +7542,9 @@ static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
                return SIZE_MAX;
 #endif
 
+       if (sq_offset)
+               *sq_offset = off;
+
        sq_array_size = array_size(sizeof(u32), sq_entries);
        if (sq_array_size == SIZE_MAX)
                return SIZE_MAX;
@@ -7093,9 +7552,6 @@ static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
        if (check_add_overflow(off, sq_array_size, &off))
                return SIZE_MAX;
 
-       if (sq_offset)
-               *sq_offset = off;
-
        return off;
 }
 
@@ -7124,8 +7580,7 @@ static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
                for (j = 0; j < imu->nr_bvecs; j++)
                        unpin_user_page(imu->bvec[j].bv_page);
 
-               if (ctx->account_mem)
-                       io_unaccount_mem(ctx->user, imu->nr_bvecs);
+               io_unaccount_mem(ctx, imu->nr_bvecs, ACCT_PINNED);
                kvfree(imu->bvec);
                imu->nr_bvecs = 0;
        }
@@ -7208,11 +7663,9 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
                start = ubuf >> PAGE_SHIFT;
                nr_pages = end - start;
 
-               if (ctx->account_mem) {
-                       ret = io_account_mem(ctx->user, nr_pages);
-                       if (ret)
-                               goto err;
-               }
+               ret = io_account_mem(ctx, nr_pages, ACCT_PINNED);
+               if (ret)
+                       goto err;
 
                ret = 0;
                if (!pages || nr_pages > got_pages) {
@@ -7225,8 +7678,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
                                        GFP_KERNEL);
                        if (!pages || !vmas) {
                                ret = -ENOMEM;
-                               if (ctx->account_mem)
-                                       io_unaccount_mem(ctx->user, nr_pages);
+                               io_unaccount_mem(ctx, nr_pages, ACCT_PINNED);
                                goto err;
                        }
                        got_pages = nr_pages;
@@ -7236,8 +7688,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
                                                GFP_KERNEL);
                ret = -ENOMEM;
                if (!imu->bvec) {
-                       if (ctx->account_mem)
-                               io_unaccount_mem(ctx->user, nr_pages);
+                       io_unaccount_mem(ctx, nr_pages, ACCT_PINNED);
                        goto err;
                }
 
@@ -7268,8 +7719,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
                         */
                        if (pret > 0)
                                unpin_user_pages(pages, pret);
-                       if (ctx->account_mem)
-                               io_unaccount_mem(ctx->user, nr_pages);
+                       io_unaccount_mem(ctx, nr_pages, ACCT_PINNED);
                        kvfree(imu->bvec);
                        goto err;
                }
@@ -7353,11 +7803,12 @@ static void io_destroy_buffers(struct io_ring_ctx *ctx)
 static void io_ring_ctx_free(struct io_ring_ctx *ctx)
 {
        io_finish_async(ctx);
-       if (ctx->sqo_mm)
+       io_sqe_buffer_unregister(ctx);
+       if (ctx->sqo_mm) {
                mmdrop(ctx->sqo_mm);
+               ctx->sqo_mm = NULL;
+       }
 
-       io_iopoll_reap_events(ctx);
-       io_sqe_buffer_unregister(ctx);
        io_sqe_files_unregister(ctx);
        io_eventfd_unregister(ctx);
        io_destroy_buffers(ctx);
@@ -7421,11 +7872,8 @@ static int io_remove_personalities(int id, void *p, void *data)
 
 static void io_ring_exit_work(struct work_struct *work)
 {
-       struct io_ring_ctx *ctx;
-
-       ctx = container_of(work, struct io_ring_ctx, exit_work);
-       if (ctx->rings)
-               io_cqring_overflow_flush(ctx, true);
+       struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
+                                              exit_work);
 
        /*
         * If we're doing polled IO and end up having requests being
@@ -7433,11 +7881,11 @@ static void io_ring_exit_work(struct work_struct *work)
         * we're waiting for refs to drop. We need to reap these manually,
         * as nobody else will be looking for them.
         */
-       while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20)) {
-               io_iopoll_reap_events(ctx);
+       do {
                if (ctx->rings)
                        io_cqring_overflow_flush(ctx, true);
-       }
+               io_iopoll_try_reap_events(ctx);
+       } while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20));
        io_ring_ctx_free(ctx);
 }
 
@@ -7453,10 +7901,10 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
        if (ctx->io_wq)
                io_wq_cancel_all(ctx->io_wq);
 
-       io_iopoll_reap_events(ctx);
        /* if we failed setting up the ctx, we might not have any rings */
        if (ctx->rings)
                io_cqring_overflow_flush(ctx, true);
+       io_iopoll_try_reap_events(ctx);
        idr_for_each(&ctx->personality_idr, io_remove_personalities, ctx);
 
        /*
@@ -7464,9 +7912,8 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
         * is closed but resources aren't reaped yet. This can cause
         * spurious failure in setting up a new ring.
         */
-       if (ctx->account_mem)
-               io_unaccount_mem(ctx->user,
-                               ring_pages(ctx->sq_entries, ctx->cq_entries));
+       io_unaccount_mem(ctx, ring_pages(ctx->sq_entries, ctx->cq_entries),
+                        ACCT_LOCKED);
 
        INIT_WORK(&ctx->exit_work, io_ring_exit_work);
        queue_work(system_wq, &ctx->exit_work);
@@ -7522,17 +7969,14 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx,
 
                if (cancel_req->flags & REQ_F_OVERFLOW) {
                        spin_lock_irq(&ctx->completion_lock);
-                       list_del(&cancel_req->list);
+                       list_del(&cancel_req->compl.list);
                        cancel_req->flags &= ~REQ_F_OVERFLOW;
-                       if (list_empty(&ctx->cq_overflow_list)) {
-                               clear_bit(0, &ctx->sq_check_overflow);
-                               clear_bit(0, &ctx->cq_check_overflow);
-                               ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW;
-                       }
-                       spin_unlock_irq(&ctx->completion_lock);
 
+                       io_cqring_mark_overflow(ctx);
                        WRITE_ONCE(ctx->rings->cq_overflow,
                                atomic_inc_return(&ctx->cached_cq_overflow));
+                       io_commit_cqring(ctx);
+                       spin_unlock_irq(&ctx->completion_lock);
 
                        /*
                         * Put inflight ref and overflow ref. If that's
@@ -7655,8 +8099,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
        int submitted = 0;
        struct fd f;
 
-       if (current->task_works)
-               task_work_run();
+       io_run_task_work();
 
        if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP))
                return -EINVAL;
@@ -7695,8 +8138,6 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
                        goto out;
        }
        if (flags & IORING_ENTER_GETEVENTS) {
-               unsigned nr_events = 0;
-
                min_complete = min(min_complete, ctx->cq_entries);
 
                /*
@@ -7707,7 +8148,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
                 */
                if (ctx->flags & IORING_SETUP_IOPOLL &&
                    !(ctx->flags & IORING_SETUP_SQPOLL)) {
-                       ret = io_iopoll_check(ctx, &nr_events, min_complete);
+                       ret = io_iopoll_check(ctx, min_complete);
                } else {
                        ret = io_cqring_wait(ctx, min_complete, sig, sigsz);
                }
@@ -7828,6 +8269,10 @@ static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
        struct io_rings *rings;
        size_t size, sq_array_offset;
 
+       /* make sure these are sane, as we already accounted them */
+       ctx->sq_entries = p->sq_entries;
+       ctx->cq_entries = p->cq_entries;
+
        size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset);
        if (size == SIZE_MAX)
                return -EOVERFLOW;
@@ -7844,8 +8289,6 @@ static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
        rings->cq_ring_entries = p->cq_entries;
        ctx->sq_mask = rings->sq_ring_mask;
        ctx->cq_mask = rings->cq_ring_mask;
-       ctx->sq_entries = rings->sq_ring_entries;
-       ctx->cq_entries = rings->cq_ring_entries;
 
        size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
        if (size == SIZE_MAX) {
@@ -7912,7 +8355,7 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
 {
        struct user_struct *user = NULL;
        struct io_ring_ctx *ctx;
-       bool account_mem;
+       bool limit_mem;
        int ret;
 
        if (!entries)
@@ -7951,10 +8394,10 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
        }
 
        user = get_uid(current_user());
-       account_mem = !capable(CAP_IPC_LOCK);
+       limit_mem = !capable(CAP_IPC_LOCK);
 
-       if (account_mem) {
-               ret = io_account_mem(user,
+       if (limit_mem) {
+               ret = __io_account_mem(user,
                                ring_pages(p->sq_entries, p->cq_entries));
                if (ret) {
                        free_uid(user);
@@ -7964,17 +8407,26 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
 
        ctx = io_ring_ctx_alloc(p);
        if (!ctx) {
-               if (account_mem)
-                       io_unaccount_mem(user, ring_pages(p->sq_entries,
+               if (limit_mem)
+                       __io_unaccount_mem(user, ring_pages(p->sq_entries,
                                                                p->cq_entries));
                free_uid(user);
                return -ENOMEM;
        }
        ctx->compat = in_compat_syscall();
-       ctx->account_mem = account_mem;
        ctx->user = user;
        ctx->creds = get_current_cred();
 
+       /*
+        * Account memory _before_ installing the file descriptor. Once
+        * the descriptor is installed, it can get closed at any time. Also
+        * do this before hitting the general error path, as ring freeing
+        * will un-account as well.
+        */
+       io_account_mem(ctx, ring_pages(p->sq_entries, p->cq_entries),
+                      ACCT_LOCKED);
+       ctx->limit_mem = limit_mem;
+
        ret = io_allocate_scq_urings(ctx, p);
        if (ret)
                goto err;
@@ -8003,12 +8455,14 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
 
        p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
                        IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
-                       IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL;
+                       IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |
+                       IORING_FEAT_POLL_32BITS;
 
        if (copy_to_user(params, p, sizeof(*p))) {
                ret = -EFAULT;
                goto err;
        }
+
        /*
         * Install ring fd as the very last thing, so we don't risk someone
         * having closed it before we finish setup
@@ -8292,7 +8746,8 @@ static int __init io_uring_init(void)
        BUILD_BUG_SQE_ELEM(28, /* compat */   int, rw_flags);
        BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);
        BUILD_BUG_SQE_ELEM(28, __u32,  fsync_flags);
-       BUILD_BUG_SQE_ELEM(28, __u16,  poll_events);
+       BUILD_BUG_SQE_ELEM(28, /* compat */ __u16,  poll_events);
+       BUILD_BUG_SQE_ELEM(28, __u32,  poll32_events);
        BUILD_BUG_SQE_ELEM(28, __u32,  sync_range_flags);
        BUILD_BUG_SQE_ELEM(28, __u32,  msg_flags);
        BUILD_BUG_SQE_ELEM(28, __u32,  timeout_flags);