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:
Jens Axboe
2023-01-21 10:39:22 -07:00
committed by Treehugger Robot
parent a64d6ea01b
commit 63bf975936

View File

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