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: Dylan Yudaken <dylany@fb.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index d0f3e084da16ef782806136d25cfcbf589907218..c9efb1d32fd28d652e181e84ecdb87d1a1fe1ba0 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -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;