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io_uring: allow re-poll if we made progress

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commit 10c873334febaeea9aa0c25c10b5ac0951b77a5f upstream.

We currently check REQ_F_POLLED before arming async poll for a
notification to retry. If it's set, then we don't allow poll and will
punt to io-wq instead. This is done to prevent a situation where a buggy
driver will repeatedly return that there's space/data available yet we
get -EAGAIN.

However, if we already transferred data, then it should be safe to rely
on poll again. Gate the check on whether or not REQ_F_PARTIAL_IO is
also set.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jens Axboe 2023-01-21 10:39:22 -07:00 committed by Greg Kroah-Hartman
parent 3c1a3d0269
commit a79b13f249
1 changed files with 5 additions and 2 deletions
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7
io_uring/io_uring.c
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@ -5853,7 +5853,7 @@ static int io_arm_poll_handler(struct io_kiocb *req)
if (!req->file || !file_can_poll(req->file))
return IO_APOLL_ABORTED;
if (req->flags & REQ_F_POLLED)
if ((req->flags & (REQ_F_POLLED|REQ_F_PARTIAL_IO)) == REQ_F_POLLED)
return IO_APOLL_ABORTED;
if (!def->pollin && !def->pollout)
return IO_APOLL_ABORTED;
@ -5869,7 +5869,10 @@ static int io_arm_poll_handler(struct io_kiocb *req)
mask |= POLLOUT | POLLWRNORM;
}
apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
if (req->flags & REQ_F_POLLED)
apoll = req->apoll;
else
apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
if (unlikely(!apoll))
return IO_APOLL_ABORTED;
apoll->double_poll = NULL;