IO-Uring Archive on lore.kernel.org
 help / color / Atom feed
From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
To: io-uring <io-uring@vger.kernel.org>, "axboe@kernel.dk" <axboe@kernel.dk>
Cc: Dust.li@linux.alibaba.com
Subject: [PATCH] io_uring: fix req cannot arm poll after polled
Date: Tue, 30 Jun 2020 20:41:14 +0800
Message-ID: <2ebb186ebbef9c5a01e27317aae664e9011acf86.1593520864.git.xuanzhuo@linux.alibaba.com> (raw)

For example, there are multiple sqes recv with the same connection.
When there is no data in the connection, the reqs of these sqes will
be armed poll. Then if only a little data is received, only one req
receives the data, and the other reqs get EAGAIN again. However,
due to this flags REQ_F_POLLED, these reqs cannot enter the
io_arm_poll_handler function. These reqs will be put into wq by
io_queue_async_work, and the flags passed by io_wqe_worker when recv
is called are BLOCK, which may make io_wqe_worker enter schedule in the
network protocol stack. When the main process of io_uring exits,
these io_wqe_workers still cannot exit. The connection will not be
actively released until the connection is closed by the peer.

So we should allow req to arm poll again.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 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 e507737..a309832 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4406,7 +4406,7 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
 
 	if (!req->file || !file_can_poll(req->file))
 		return false;
-	if (req->flags & (REQ_F_MUST_PUNT | REQ_F_POLLED))
+	if (req->flags & REQ_F_MUST_PUNT)
 		return false;
 	if (!def->pollin && !def->pollout)
 		return false;
-- 
1.8.3.1


             reply index

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-30 12:41 Xuan Zhuo [this message]
2020-06-30 12:59 ` Pavel Begunkov
2020-06-30 14:02 ` Jens Axboe
2020-07-01 12:47 ` Xuan Zhuo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=2ebb186ebbef9c5a01e27317aae664e9011acf86.1593520864.git.xuanzhuo@linux.alibaba.com \
    --to=xuanzhuo@linux.alibaba.com \
    --cc=Dust.li@linux.alibaba.com \
    --cc=axboe@kernel.dk \
    --cc=io-uring@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

IO-Uring Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/io-uring/0 io-uring/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 io-uring io-uring/ https://lore.kernel.org/io-uring \
		io-uring@vger.kernel.org
	public-inbox-index io-uring

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.io-uring


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git