Commit b4aec400 authored by Dylan Yudaken's avatar Dylan Yudaken Committed by Jens Axboe
Browse files

io_uring: do not recalculate ppos unnecessarily 



There is a slight optimisation to be had by calculating the correct pos
pointer inside io_kiocb_update_pos and then using that later.

It seems code size drops by a bit:
000000000000a1b0 0000000000000400 t io_read
000000000000a5b0 0000000000000319 t io_write

vs
000000000000a1b0 00000000000003f6 t io_read
000000000000a5b0 0000000000000310 t io_write

Signed-off-by: default avatarDylan Yudaken <dylany@fb.com>
Reviewed-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent d34e1e5b

fs/io_uring.c

+12 −6
Original line number Diff line number Diff line
@@ -3086,18 +3086,22 @@ static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) 
	}

}



static inline void io_kiocb_update_pos(struct io_kiocb *req)

static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)

{

	struct kiocb *kiocb = &req->rw.kiocb;

	bool is_stream = req->file->f_mode & FMODE_STREAM;



	if (kiocb->ki_pos == -1) {

		if (!(req->file->f_mode & FMODE_STREAM)) {

		if (!is_stream) {

			req->flags |= REQ_F_CUR_POS;

			kiocb->ki_pos = req->file->f_pos;

			return &kiocb->ki_pos;

		} else {

			kiocb->ki_pos = 0;

			return NULL;

		}

	}

	return is_stream ? NULL : &kiocb->ki_pos;

}



static void kiocb_done(struct io_kiocb *req, ssize_t ret,
@@ -3658,6 +3662,7 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags) 
	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;

	struct io_async_rw *rw;

	ssize_t ret, ret2;

	loff_t *ppos;



	if (!req_has_async_data(req)) {

		ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
@@ -3688,9 +3693,9 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags) 
		kiocb->ki_flags &= ~IOCB_NOWAIT;

	}



	io_kiocb_update_pos(req);

	ppos = io_kiocb_update_pos(req);



	ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), req->result);

	ret = rw_verify_area(READ, req->file, ppos, req->result);

	if (unlikely(ret)) {

		kfree(iovec);

		return ret;
@@ -3789,6 +3794,7 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags) 
	struct kiocb *kiocb = &req->rw.kiocb;

	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;

	ssize_t ret, ret2;

	loff_t *ppos;



	if (!req_has_async_data(req)) {

		ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags);
@@ -3819,9 +3825,9 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags) 
		kiocb->ki_flags &= ~IOCB_NOWAIT;

	}



	io_kiocb_update_pos(req);

	ppos = io_kiocb_update_pos(req);



	ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), req->result);

	ret = rw_verify_area(WRITE, req->file, ppos, req->result);

	if (unlikely(ret))

		goto out_free;