From: weiping zhang <zhangweiping@didichuxing.com>
Date: Thu, 23 Nov 2017 21:39:40 +0800
Subject: [PATCH] blk-sysfs: remove NULL pointer checking in queue_wb_lat_store
Git-commit: f680474345f1fd6329d1806d6358066fd3b07f02
Patch-mainline: v4.15-rc2
References: bsc#1104967,FATE#325924

wbt_init doesn't set q->rq_wb to NULL, if wbt_init return 0,
so check return value is enough, remove NULL checking.

Signed-off-by: weiping zhang <zhangweiping@didichuxing.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 block/blk-sysfs.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index e54be402899d..870484eaed1f 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -450,12 +450,9 @@ static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 		ret = wbt_init(q);
 		if (ret)
 			return ret;
-
-		rwb = q->rq_wb;
-		if (!rwb)
-			return -EINVAL;
 	}
 
+	rwb = q->rq_wb;
 	if (val == -1)
 		rwb->min_lat_nsec = wbt_default_latency_nsec(q);
 	else if (val >= 0)
-- 
2.16.4