From: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Date: Mon, 7 Mar 2011 08:28:09 +0000 (+0100)
Subject: cfq-iosched: Fix update_vdisktime logic
X-Git-Tag: firefly_0821_release~7613^2~1808^2~42
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a60327107b56573c305ecc78e471dbdbb4d2f426;p=firefly-linux-kernel-4.4.55.git

cfq-iosched: Fix update_vdisktime logic

The update_vdisktime logic is broken since commit
b54ce60eb7f61f8e314b8b241b0469eda3bb1d42, st->min_vdisktime never makes
a progress. Fix it.

Thanks Vivek for pointing it out.

Signed-off-by: Gui Jianfeng <guijianfen@cn.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
---

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 135b1a48da23..938ae52aa927 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -557,15 +557,13 @@ static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime)
 
 static void update_min_vdisktime(struct cfq_rb_root *st)
 {
-	u64 vdisktime = st->min_vdisktime;
 	struct cfq_group *cfqg;
 
 	if (st->left) {
 		cfqg = rb_entry_cfqg(st->left);
-		vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime);
+		st->min_vdisktime = max_vdisktime(st->min_vdisktime,
+						  cfqg->vdisktime);
 	}
-
-	st->min_vdisktime = max_vdisktime(st->min_vdisktime, vdisktime);
 }
 
 /*