UPSTREAM: io_uring: allow re-poll if we made progress
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.
Change-Id: I36b6d16ac43202fdf9ae5eea64f9dfbcfbe7fee5
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Bug: 268174392
(cherry picked from commit 4bc17e6381
)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:

committed by
Treehugger Robot

parent
a64d6ea01b
commit
63bf975936
@@ -5704,7 +5704,7 @@ static int io_arm_poll_handler(struct io_kiocb *req)
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if (!req->file || !file_can_poll(req->file))
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return IO_APOLL_ABORTED;
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if (req->flags & REQ_F_POLLED)
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if ((req->flags & (REQ_F_POLLED|REQ_F_PARTIAL_IO)) == REQ_F_POLLED)
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return IO_APOLL_ABORTED;
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if (!def->pollin && !def->pollout)
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return IO_APOLL_ABORTED;
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@@ -5720,6 +5720,9 @@ static int io_arm_poll_handler(struct io_kiocb *req)
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mask |= POLLOUT | POLLWRNORM;
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}
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if (req->flags & REQ_F_POLLED)
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apoll = req->apoll;
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else
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apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
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if (unlikely(!apoll))
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return IO_APOLL_ABORTED;
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