From: Christoph Hellwig <hch@lst.de>
Date: Sat, 27 Jun 2020 09:31:57 +0200
Subject: [PATCH] blk-cgroup: move rcu locking from blkcg_bio_issue_check to
Git-commit: 93b8063804b62b55248e16499d853e1b20eff905
Patch-mainline: v5.9-rc1
References: bsc#1175995,jsc#SLE-15608
blk_throtl_bio
The only thing in blkcg_bio_issue_check that needs to be under
rcu_read_lock is blk_throtl_bio, so move the locking there.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
block/blk-throttle.c | 3 ++-
include/linux/blk-cgroup.h | 2 --
2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 209fdd8939fb..ac0083450500 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -2168,7 +2168,7 @@ bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
bool throttled = false;
struct throtl_data *td = tg->td;
- WARN_ON_ONCE(!rcu_read_lock_held());
+ rcu_read_lock();
/* see throtl_charge_bio() */
if (bio_flagged(bio, BIO_THROTTLED))
@@ -2273,6 +2273,7 @@ bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
if (throttled || !td->track_bio_latency)
bio->bi_issue.value |= BIO_ISSUE_THROTL_SKIP_LATENCY;
#endif
+ rcu_read_unlock();
return throttled;
}
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 8e86b598316c..8ab043c911f2 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -546,7 +546,6 @@ static inline bool blkcg_bio_issue_check(struct request_queue *q,
struct blkcg_gq *blkg = bio->bi_blkg;
bool throtl = false;
- rcu_read_lock();
throtl = blk_throtl_bio(q, blkg, bio);
if (!throtl) {
struct blkg_iostat_set *bis;
@@ -582,7 +581,6 @@ static inline bool blkcg_bio_issue_check(struct request_queue *q,
blkcg_bio_issue_init(bio);
- rcu_read_unlock();
return !throtl;
}
--
2.16.4