Commit 56952e91 authored Jun 17, 2020 by Jens Axboe

io_uring: reap poll completions while waiting for refs to drop on exit



If we're doing polled IO and end up having requests being submitted
async, then completions can come in while we're waiting for refs to
drop. We need to reap these manually, as nobody else will be looking
for them.

Break the wait into 1/20th of a second time waits, and check for done
poll completions if we time out. Otherwise we can have done poll
completions sitting in ctx->poll_list, which needs us to reap them but
we're just waiting for them.

Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 9d8426a0

fs/io_uring.c

+11 −1

Original line number	Diff line number	Diff line
		@@ -7363,7 +7363,17 @@ static void io_ring_exit_work(struct work_struct *work)
		if (ctx->rings)
		io_cqring_overflow_flush(ctx, true);

		wait_for_completion(&ctx->ref_comp);
		/*
		* If we're doing polled IO and end up having requests being
		* submitted async (out-of-line), then completions can come in while
		* we're waiting for refs to drop. We need to reap these manually,
		* as nobody else will be looking for them.
		*/
		while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20)) {
		io_iopoll_reap_events(ctx);
		if (ctx->rings)
		io_cqring_overflow_flush(ctx, true);
		}
		io_ring_ctx_free(ctx);
		}

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