Commit f6b543fd authored Jul 21, 2022 by Jens Axboe

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: 584b0180 ("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>

parent 4f6a94d3

io_uring/io_uring.c

+3 −0

Original line number	Original line	Diff line number	Diff line
	@@ -406,6 +406,9 @@ static void io_prep_async_work(struct io_kiocb *req)
	if (req->flags & REQ_F_FORCE_ASYNC)		if (req->flags & REQ_F_FORCE_ASYNC)
	req->work.flags \|= IO_WQ_WORK_CONCURRENT;		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 (req->flags & REQ_F_ISREG) {
	if (def->hash_reg_file \|\| (ctx->flags & IORING_SETUP_IOPOLL))		if (def->hash_reg_file \|\| (ctx->flags & IORING_SETUP_IOPOLL))
	io_wq_hash_work(&req->work, file_inode(req->file));		io_wq_hash_work(&req->work, file_inode(req->file));

io_uring/io_uring.h

+5 −0

Original line number	Original line	Diff line number	Diff line
	@@ -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,		struct file io_file_get_fixed(struct io_kiocb req, int fd,
	unsigned issue_flags);		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_is_uring_fops(struct file *file);
	bool io_alloc_async_data(struct io_kiocb *req);		bool io_alloc_async_data(struct io_kiocb *req);
	void io_req_task_work_add(struct io_kiocb *req);		void io_req_task_work_add(struct io_kiocb *req);

io_uring/rw.c

+0 −5

Original line number	Original line	Diff line number	Diff line
	@@ -647,11 +647,6 @@ static bool need_read_all(struct io_kiocb *req)
	S_ISBLK(file_inode(req->file)->i_mode);		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)		static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
	{		{
	struct io_rw *rw = io_kiocb_to_cmd(req);		struct io_rw *rw = io_kiocb_to_cmd(req);