io_uring: store io_identity in io_uring_task

This is, by definition, a per-task structure. So store it in the
task context, instead of doing carrying it in each io_kiocb. We're being
a bit inefficient if members have changed, as that requires an alloc and
copy of a new io_identity struct. The next patch will fix that up.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index ab30834..ae91632 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -689,7 +689,6 @@ struct io_kiocb {
        struct hlist_node               hash_node;
        struct async_poll               *apoll;
        struct io_wq_work               work;
-       struct io_identity              identity;
 };
 
 struct io_defer_entry {
@@ -1072,8 +1071,7 @@ static inline void io_req_init_async(struct io_kiocb *req)
 
        memset(&req->work, 0, sizeof(req->work));
        req->flags |= REQ_F_WORK_INITIALIZED;
-       io_init_identity(&req->identity);
-       req->work.identity = &req->identity;
+       req->work.identity = &current->io_uring->identity;
 }
 
 static inline bool io_async_submit(struct io_ring_ctx *ctx)
@@ -1179,9 +1177,9 @@ static void __io_commit_cqring(struct io_ring_ctx *ctx)
        }
 }
 
-static void io_put_identity(struct io_kiocb *req)
+static void io_put_identity(struct io_uring_task *tctx, struct io_kiocb *req)
 {
-       if (req->work.identity == &req->identity)
+       if (req->work.identity == &tctx->identity)
                return;
        if (refcount_dec_and_test(&req->work.identity->count))
                kfree(req->work.identity);
@@ -1220,7 +1218,7 @@ static void io_req_clean_work(struct io_kiocb *req)
                req->work.flags &= ~IO_WQ_WORK_FS;
        }
 
-       io_put_identity(req);
+       io_put_identity(req->task->io_uring, req);
 }
 
 /*
@@ -1229,6 +1227,7 @@ static void io_req_clean_work(struct io_kiocb *req)
  */
 static bool io_identity_cow(struct io_kiocb *req)
 {
+       struct io_uring_task *tctx = current->io_uring;
        const struct cred *creds = NULL;
        struct io_identity *id;
 
@@ -1255,7 +1254,7 @@ static bool io_identity_cow(struct io_kiocb *req)
        refcount_inc(&id->count);
 
        /* drop old identity, assign new one. one ref for req, one for tctx */
-       if (req->work.identity != &req->identity &&
+       if (req->work.identity != &tctx->identity &&
            refcount_sub_and_test(2, &req->work.identity->count))
                kfree(req->work.identity);
 
@@ -1266,7 +1265,7 @@ static bool io_identity_cow(struct io_kiocb *req)
 static bool io_grab_identity(struct io_kiocb *req)
 {
        const struct io_op_def *def = &io_op_defs[req->opcode];
-       struct io_identity *id = &req->identity;
+       struct io_identity *id = req->work.identity;
        struct io_ring_ctx *ctx = req->ctx;
 
        if (def->needs_fsize && id->fsize != rlimit(RLIMIT_FSIZE))
@@ -1330,10 +1329,11 @@ static bool io_grab_identity(struct io_kiocb *req)
 static void io_prep_async_work(struct io_kiocb *req)
 {
        const struct io_op_def *def = &io_op_defs[req->opcode];
-       struct io_identity *id = &req->identity;
        struct io_ring_ctx *ctx = req->ctx;
+       struct io_identity *id;
 
        io_req_init_async(req);
+       id = req->work.identity;
 
        if (req->flags & REQ_F_ISREG) {
                if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL))
@@ -6481,7 +6481,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
                if (unlikely(!iod))
                        return -EINVAL;
                refcount_inc(&iod->count);
-               io_put_identity(req);
+               io_put_identity(current->io_uring, req);
                get_cred(iod->creds);
                req->work.identity = iod;
                req->work.flags |= IO_WQ_WORK_CREDS;
@@ -7691,6 +7691,7 @@ static int io_uring_alloc_task_context(struct task_struct *task)
        tctx->in_idle = 0;
        atomic_long_set(&tctx->req_issue, 0);
        atomic_long_set(&tctx->req_complete, 0);
+       io_init_identity(&tctx->identity);
        task->io_uring = tctx;
        return 0;
 }

diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index 342cc57..bd33461 100644 (file)
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -24,6 +24,7 @@ struct io_uring_task {
        struct wait_queue_head  wait;
        struct file             *last;
        atomic_long_t           req_issue;
+       struct io_identity      identity;
 
        /* completion side */
        bool                    in_idle ____cacheline_aligned_in_smp;