[PATCH 4.19 118/421] blk-wbt: make sure throttle is enabled properly

Greg Kroah-Hartman
2021-07-19T16:09:39Z

From: Zhang Yi <yi.zhang@huawei.com>

[ Upstream commit 76a8040817b4b9c69b53f9b326987fa891b4082a ]

After commit a79050434b45 ("blk-rq-qos: refactor out common elements of
blk-wbt"), if throttle was disabled by wbt_disable_default(), we could
not enable again, fix this by set enable_state back to
WBT_STATE_ON_DEFAULT.

Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt")
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20210619093700.920393-3-yi.zhang@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/blk-wbt.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index 08623f37617f..880a41adde8f 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -704,9 +704,13 @@ void wbt_set_write_cache(struct request_queue *q, bool write_cache_on)
void wbt_enable_default(struct request_queue *q)
{
struct rq_qos *rqos = wbt_rq_qos(q);
+
/* Throttling already enabled? */
- if (rqos)
+ if (rqos) {
+ if (RQWB(rqos)->enable_state == WBT_STATE_OFF_DEFAULT)
+ RQWB(rqos)->enable_state = WBT_STATE_ON_DEFAULT;
return;
+ }

/* Queue not registered? Maybe shutting down... */
if (!blk_queue_registered(q))
--
2.30.2