io_uring: fix invalid ctx->sq_thread_idle

We have to set ctx->sq_thread_idle before adding a ring to an SQ task,
otherwise sqd races for seeing zero and accounting it as such.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -7829,14 +7829,14 @@ static int io_sq_offload_create(struct io_ring_ctx *ctx,
 
 		ctx->sq_creds = get_current_cred();
 		ctx->sq_data = sqd;
-		io_sq_thread_park(sqd);
-		list_add(&ctx->sqd_list, &sqd->ctx_new_list);
-		io_sq_thread_unpark(sqd);
-
 		ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle);
 		if (!ctx->sq_thread_idle)
 			ctx->sq_thread_idle = HZ;
 
+		io_sq_thread_park(sqd);
+		list_add(&ctx->sqd_list, &sqd->ctx_new_list);
+		io_sq_thread_unpark(sqd);
+
 		if (sqd->thread)
 			return 0;