io_uring: retry poll if we got woken with non-matching mask (a6ba632d) · Commits · 戴 / test

If we get woken and the poll doesn't match our mask, re-add the task to the poll waitqueue and try again instead of completing the request with a mask of 0. Reported-by:

Dan Melnic <dmm@fb.com> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -4412,8 +4412,20 @@ static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error)
		static void io_poll_task_handler(struct io_kiocb req, struct io_kiocb *nxt)
		{
		struct io_ring_ctx *ctx = req->ctx;
		struct io_poll_iocb *poll = &req->poll;

		if (!req->result && !READ_ONCE(poll->canceled)) {
		struct poll_table_struct pt = { ._key = poll->events };

		req->result = vfs_poll(req->file, &pt) & poll->events;
		}

		spin_lock_irq(&ctx->completion_lock);
		if (!req->result && !READ_ONCE(poll->canceled)) {
		add_wait_queue(poll->head, &poll->wait);
		spin_unlock_irq(&ctx->completion_lock);
		return;
		}
		hash_del(&req->hash_node);
		io_poll_complete(req, req->result, 0);
		req->flags \|= REQ_F_COMP_LOCKED;

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