io_uring: ensure REQ_F_ISREG is set async offload

If we're offloading requests directly to io-wq because IOSQE_ASYNC was
set in the sqe, we can miss hashing writes appropriately because we
haven't set REQ_F_ISREG yet. This can cause a performance regression
with buffered writes, as io-wq then no longer correctly serializes writes
to that file.

Ensure that we set the flags in io_prep_async_work(), which will cause
the io-wq work item to be hashed appropriately.

Fixes: 584b0180f0f4 ("io_uring: move read/write file prep state into actual opcode handler")
Link: https://lore.kernel.org/io-uring/20220608080054.GB22428@xsang-OptiPlex-9020/
Reported-by: kernel test robot <oliver.sang@intel.com>
Tested-by: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 624535c..4b3fd64 100644 (file)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -406,6 +406,9 @@ static void io_prep_async_work(struct io_kiocb *req)
        if (req->flags & REQ_F_FORCE_ASYNC)
                req->work.flags |= IO_WQ_WORK_CONCURRENT;
 
+       if (req->file && !io_req_ffs_set(req))
+               req->flags |= io_file_get_flags(req->file) << REQ_F_SUPPORT_NOWAIT_BIT;
+
        if (req->flags & REQ_F_ISREG) {
                if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL))
                        io_wq_hash_work(&req->work, file_inode(req->file));

diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index 868f45d..5db0a60 100644 (file)
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -41,6 +41,11 @@ struct file *io_file_get_normal(struct io_kiocb *req, int fd);
 struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
                               unsigned issue_flags);
 
+static inline bool io_req_ffs_set(struct io_kiocb *req)
+{
+       return req->flags & REQ_F_FIXED_FILE;
+}
+
 bool io_is_uring_fops(struct file *file);
 bool io_alloc_async_data(struct io_kiocb *req);
 void io_req_task_work_add(struct io_kiocb *req);

diff --git a/io_uring/rw.c b/io_uring/rw.c
index ade3e23..c50a0d6 100644 (file)
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -647,11 +647,6 @@ static bool need_read_all(struct io_kiocb *req)
                S_ISBLK(file_inode(req->file)->i_mode);
 }
 
-static inline bool io_req_ffs_set(struct io_kiocb *req)
-{
-       return req->flags & REQ_F_FIXED_FILE;
-}
-
 static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
 {
        struct io_rw *rw = io_kiocb_to_cmd(req);