[PATCH] io_uring: fix req cannot arm poll after polled

[Xuan Zhuo <xuanzhuo@linux.alibaba.com>]

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