From: "Maciej S. Szmigiero" <mail@maciej.szmigiero.name>
Date: Wed, 10 Oct 2018 23:16:50 +0200
Subject: [PATCH] cfq: clear queue pointers from cfqg after unpinning them in
Git-commit: a2fa8a19b75b5a649db2a6bec892ff5e03a23e76
Patch-mainline: v4.20-rc1
References: bsc#1104967,FATE#325924
cfq_pd_offline
BFQ is already doing a similar thing in its .pd_offline_fn() method
implementation.
While it seems that after commit 4c6994806f70
("blk-throttle: fix race between blkcg_bio_issue_check() and cgroup_rmdir()")
was reverted leaving these pointers intact no longer causes crashes
clearing them is still a sensible thing to do to make the code more robust.
Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
block/cfq-iosched.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index d219e9a1af65..6a3d87dd3c1a 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1644,14 +1644,20 @@ static void cfq_pd_offline(struct blkg_policy_data *pd)
int i;
for (i = 0; i < IOPRIO_BE_NR; i++) {
- if (cfqg->async_cfqq[0][i])
+ if (cfqg->async_cfqq[0][i]) {
cfq_put_queue(cfqg->async_cfqq[0][i]);
- if (cfqg->async_cfqq[1][i])
+ cfqg->async_cfqq[0][i] = NULL;
+ }
+ if (cfqg->async_cfqq[1][i]) {
cfq_put_queue(cfqg->async_cfqq[1][i]);
+ cfqg->async_cfqq[1][i] = NULL;
+ }
}
- if (cfqg->async_idle_cfqq)
+ if (cfqg->async_idle_cfqq) {
cfq_put_queue(cfqg->async_idle_cfqq);
+ cfqg->async_idle_cfqq = NULL;
+ }
/*
* @blkg is going offline and will be ignored by
--
2.16.4