Commit 82733d16 authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: stop using io_wq_work as an fd placeholder 



There are two reasons why this isn't the best idea:

- It's an odd area to grab a bit of storage space, hence it's an odd area
  to grab storage from.
- It puts the 3rd io_kiocb cacheline into the hot path, where normal hot
  path just needs the first two.

Use 'cflags' for joint fd/cflags storage. We only need fd until we
successfully issue, and we only need cflags once a request is done and is
completed.

Fixes: 6bf9c47a ("io_uring: defer file assignment")
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 2804ecd8

fs/io-wq.h

+0 −1
Original line number Diff line number Diff line
@@ -155,7 +155,6 @@ struct io_wq_work_node *wq_stack_extract(struct io_wq_work_node *stack) 
struct io_wq_work {

	struct io_wq_work_node list;

	unsigned flags;

	int fd;

};



static inline struct io_wq_work *wq_next_work(struct io_wq_work *work)

fs/io_uring.c

+8 −4
Original line number Diff line number Diff line
@@ -907,7 +907,11 @@ struct io_kiocb { 


	u64				user_data;

	u32				result;

	/* fd initially, then cflags for completion */

	union {

		u32			cflags;

		int			fd;

	};



	struct io_ring_ctx		*ctx;

	struct task_struct		*task;
@@ -7090,9 +7094,9 @@ static bool io_assign_file(struct io_kiocb *req, unsigned int issue_flags) 
		return true;



	if (req->flags & REQ_F_FIXED_FILE)

		req->file = io_file_get_fixed(req, req->work.fd, issue_flags);

		req->file = io_file_get_fixed(req, req->fd, issue_flags);

	else

		req->file = io_file_get_normal(req, req->work.fd);

		req->file = io_file_get_normal(req, req->fd);

	if (req->file)

		return true;
@@ -7630,7 +7634,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, 
	if (io_op_defs[opcode].needs_file) {

		struct io_submit_state *state = &ctx->submit_state;



		req->work.fd = READ_ONCE(sqe->fd);

		req->fd = READ_ONCE(sqe->fd);



		/*

		 * Plug now if we have more than 2 IO left after this, and the