[PATCH v1] fs/io_uring: Prioritise checking faster conditions first in io_write

From: Noah Goldstein
Date: Sat Oct 16 2021 - 21:32:40 EST


This commit reorders the conditions in a branch in io_write. The
reorder to check 'ret2 == -EAGAIN' first as checking
'(req->ctx->flags & IORING_SETUP_IOPOLL)' will likely be more
expensive due to 2x memory derefences.

Signed-off-by: Noah Goldstein <goldstein.w.n@xxxxxxxxx>
---
fs/io_uring.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6b9e70208782..321de7ddf2cf 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3660,7 +3660,7 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags)
goto done;
if (!force_nonblock || ret2 != -EAGAIN) {
/* IOPOLL retry should happen for io-wq threads */
- if ((req->ctx->flags & IORING_SETUP_IOPOLL) && ret2 == -EAGAIN)
+ if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL))
goto copy_iov;
done:
kiocb_done(kiocb, ret2, issue_flags);
--
2.25.1