Commit 67b0025d authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring/rw: forbid multishot async reads 



At the moment we can't sanely handle queuing an async request from a
multishot context, so disable them. It shouldn't matter as pollable
files / socekts don't normally do async.

Patching it in __io_read() is not the cleanest way, but it's simpler
than other options, so let's fix it there and clean up on top.

Cc: stable@vger.kernel.org
Reported-by: default avatarchase xd <sl1589472800@gmail.com>
Fixes: fc68fcda ("io_uring/rw: add support for IORING_OP_READ_MULTISHOT")
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7d51732c125159d17db4fe16f51ec41b936973f8.1739919038.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent fb3331f5

io_uring/rw.c

+11 −2
Original line number Diff line number Diff line
@@ -880,7 +880,15 @@ static int __io_read(struct io_kiocb *req, unsigned int issue_flags) 
	if (unlikely(ret))

		return ret;



	if (unlikely(req->opcode == IORING_OP_READ_MULTISHOT)) {

		void *cb_copy = rw->kiocb.ki_complete;



		rw->kiocb.ki_complete = NULL;

		ret = io_iter_do_read(rw, &io->iter);

		rw->kiocb.ki_complete = cb_copy;

	} else {

		ret = io_iter_do_read(rw, &io->iter);

	}



	/*

	 * Some file systems like to return -EOPNOTSUPP for an IOCB_NOWAIT
@@ -904,7 +912,8 @@ static int __io_read(struct io_kiocb *req, unsigned int issue_flags) 
	} else if (ret == -EIOCBQUEUED) {

		return IOU_ISSUE_SKIP_COMPLETE;

	} else if (ret == req->cqe.res || ret <= 0 || !force_nonblock ||

		   (req->flags & REQ_F_NOWAIT) || !need_complete_io(req)) {

		   (req->flags & REQ_F_NOWAIT) || !need_complete_io(req) ||

		   (issue_flags & IO_URING_F_MULTISHOT)) {

		/* read all, failed, already did sync or don't want to retry */

		goto done;

	}