io_uring: don't reinstall quiesce node for each tw

There is no need to reinit data and install a new rsrc node every time
we get a task_work, it's detrimental, just execute it and conitnue
waiting.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3895d3344164cd9b3a0bbb24a6e357e20a13434b.1669821213.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/rsrc.c

@@ -309,22 +309,27 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
 	/* As we may drop ->uring_lock, other task may have started quiesce */
 	if (data->quiesce)
 		return -ENXIO;
+	ret = io_rsrc_node_switch_start(ctx);
+	if (ret)
+		return ret;
+	io_rsrc_node_switch(ctx, data);
+
+	/* kill initial ref, already quiesced if zero */
+	if (atomic_dec_and_test(&data->refs))
+		return 0;
 
 	data->quiesce = true;
+	mutex_unlock(&ctx->uring_lock);
 	do {
-		ret = io_rsrc_node_switch_start(ctx);
-		if (ret)
-			break;
-		io_rsrc_node_switch(ctx, data);
-
-		/* kill initial ref, already quiesced if zero */
-		if (atomic_dec_and_test(&data->refs))
-			break;
-		mutex_unlock(&ctx->uring_lock);
-
 		ret = io_run_task_work_sig(ctx);
-		if (ret < 0)
-			goto reinit;
+		if (ret < 0) {
+			atomic_inc(&data->refs);
+			/* wait for all works potentially completing data->done */
+			flush_delayed_work(&ctx->rsrc_put_work);
+			reinit_completion(&data->done);
+			mutex_lock(&ctx->uring_lock);
+			break;
+		}
 
 		flush_delayed_work(&ctx->rsrc_put_work);
 		ret = wait_for_completion_interruptible(&data->done);
@@ -338,14 +343,7 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
 			 */
 			mutex_unlock(&ctx->uring_lock);
 		}
-reinit:
-		atomic_inc(&data->refs);
-		/* wait for all works potentially completing data->done */
-		flush_delayed_work(&ctx->rsrc_put_work);
-		reinit_completion(&data->done);
-
-		mutex_lock(&ctx->uring_lock);
-	} while (ret >= 0);
+	} while (1);
 	data->quiesce = false;
 
 	return ret;