diff mbox series

[RESEND,for-5.20] io_uring/net: fix overexcessive retries

Message ID 0bc0d5179c665b4ef5c328377c84c7a1f298467e.1661530037.git.asml.silence@gmail.com (mailing list archive)
State New
Headers show
Series [RESEND,for-5.20] io_uring/net: fix overexcessive retries | expand

Commit Message

Pavel Begunkov Aug. 26, 2022, 4:15 p.m. UTC
Length parameter of io_sg_from_iter() can be smaller than the iterator's
size, as it's with TCP, so when we set from->count at the end of the
function we truncate the iterator forcing TCP to return preliminary with
a short send. It affects zerocopy sends with large payload sizes and
leads to retries and possible request failures.

Fixes: 3ff1a0d395c00 ("io_uring: enable managed frags with register buffers")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/net.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Jens Axboe Aug. 26, 2022, 6:42 p.m. UTC | #1
On Fri, 26 Aug 2022 17:15:47 +0100, Pavel Begunkov wrote:
> Length parameter of io_sg_from_iter() can be smaller than the iterator's
> size, as it's with TCP, so when we set from->count at the end of the
> function we truncate the iterator forcing TCP to return preliminary with
> a short send. It affects zerocopy sends with large payload sizes and
> leads to retries and possible request failures.
> 
> 
> [...]

Applied, thanks!

[1/1] io_uring/net: fix overexcessive retries
      (no commit info)

Best regards,
diff mbox series

Patch

diff --git a/io_uring/net.c b/io_uring/net.c
index 0af8a02df580..7a5468cc905e 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -956,7 +956,7 @@  static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,
 	shinfo->nr_frags = frag;
 	from->bvec += bi.bi_idx;
 	from->nr_segs -= bi.bi_idx;
-	from->count = bi.bi_size;
+	from->count -= copied;
 	from->iov_offset = bi.bi_bvec_done;
 
 	skb->data_len += copied;