From: Chetan Loke <loke.chetan@gmail.com>
Date: Tue, 31 Jul 2012 06:47:13 +0000 (+0200)
Subject: block/nbd: micro-optimization in nbd request completion
X-Git-Tag: firefly_0821_release~3680^2~2262^2~8
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=01ff5dbc0925d11c8ad76eed3bdd02d0c7e1e0f5;p=firefly-linux-kernel-4.4.55.git

block/nbd: micro-optimization in nbd request completion

Add in-flight cmds to the tail. That way while searching
(during request completion),we will always get a hit on the
first element.

Signed-off-by: Chetan Loke <loke.chetan@gmail.com>
Acked-by: Paul.Clements@steeleye.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 061427a75d37..8957b9f0cfad 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -481,7 +481,7 @@ static void nbd_handle_req(struct nbd_device *nbd, struct request *req)
 		nbd_end_request(req);
 	} else {
 		spin_lock(&nbd->queue_lock);
-		list_add(&req->queuelist, &nbd->queue_head);
+		list_add_tail(&req->queuelist, &nbd->queue_head);
 		spin_unlock(&nbd->queue_lock);
 	}