io_uring: signal SQPOLL task_work with TWA_SIGNAL_NO_IPI

Before SQPOLL was transitioned to managing its own task_work, the core
used TWA_SIGNAL_NO_IPI to ensure that task_work was processed. If not,
we can't be sure that all task_work is processed at SQPOLL thread exit
time.

Fixes: af5d68f8 ("io_uring/sqpoll: manage task_work privately")
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/io_uring.c

@@ -1259,8 +1259,8 @@ static void io_req_normal_work_add(struct io_kiocb *req)
 	if (ctx->flags & IORING_SETUP_SQPOLL) {
 		struct io_sq_data *sqd = ctx->sq_data;
 
-		if (wq_has_sleeper(&sqd->wait))
-			wake_up(&sqd->wait);
+		if (sqd->thread)
+			__set_notify_signal(sqd->thread);
 		return;
 	}