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Subject[PATCH v2] fs/io_uring: Hoist ret2 == -EAGAIN check in tail of io_write
Date
This commit reorganizes the branches in the tail of io_write so that
the 'ret2 == -EAGAIN' check is not repeated and done first.

The previous version was duplicating the 'ret2 == -EAGAIN'. As well
'ret2 != -EAGAIN' gurantees the 'done:' path so it makes sense to
move that check to the front before the likely more expensive branches
which require memory derefences.

Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
---
fs/io_uring.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index d1e672e7a2d1..18293407e8bc 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3648,21 +3648,19 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags)
*/
if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
ret2 = -EAGAIN;
- /* no retry on NONBLOCK nor RWF_NOWAIT */
- if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT))
- goto done;
- if (!force_nonblock || ret2 != -EAGAIN) {
- /* IOPOLL retry should happen for io-wq threads */
- if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL))
- goto copy_iov;
-done:
+
+ if (ret2 != -EAGAIN ||
+ /* no retry on NONBLOCK nor RWF_NOWAIT */
+ (req->flags & REQ_F_NOWAIT)
+ /* IOPOLL retry should happen for io-wq threads */
+ || (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))) {
kiocb_done(kiocb, ret2, issue_flags);
} else {
copy_iov:
iov_iter_restore(&s->iter, &s->iter_state);
ret = io_setup_async_rw(req, iovec, s, false);
return ret ?: -EAGAIN;
- }
+}
out_free:
/* it's reportedly faster than delegating the null check to kfree() */
if (iovec)
--
2.29.2
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