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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hao Xu <haoxu@linux.alibaba.com>,
        Jens Axboe <axboe@kernel.dk>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.14 113/162] io_uring: fix missing set of EPOLLONESHOT for CQ ring overflow
Date:   Mon, 27 Sep 2021 19:02:39 +0200
Message-Id: <20210927170237.362444454@linuxfoundation.org>
In-Reply-To: <20210927170233.453060397@linuxfoundation.org>
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From: Hao Xu <haoxu@linux.alibaba.com>

[ Upstream commit a62682f92eedb41c1cd8290fa875a4b85624fb9a ]

We should set EPOLLONESHOT if cqring_fill_event() returns false since
io_poll_add() decides to put req or not by it.

Fixes: 5082620fb2ca ("io_uring: terminate multishot poll for CQ ring overflow")
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20210922101238.7177-3-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/io_uring.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 27a1c813f1e1..739e58ccc982 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4968,8 +4968,10 @@ static bool io_poll_complete(struct io_kiocb *req, __poll_t mask)
 	}
 	if (req->poll.events & EPOLLONESHOT)
 		flags = 0;
-	if (!io_cqring_fill_event(ctx, req->user_data, error, flags))
+	if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) {
+		req->poll.events |= EPOLLONESHOT;
 		flags = 0;
+	}
 	if (flags & IORING_CQE_F_MORE)
 		ctx->cq_extra++;
 
-- 
2.33.0