[PATCH 12/14] blk-cgroup: move rcu locking from blkcg_bio_issue_check to blk_throtl_bio
From: Christoph Hellwig <hch@lst.de>
Date: 2020-06-27 07:33:17
Also in:
cgroups, dm-devel, linux-mm, lkml
Subsystem:
block layer, control group - block io controller (blkio), the rest · Maintainers:
Jens Axboe, Tejun Heo, Josef Bacik, Linus Torvalds
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. Signed-off-by: Christoph Hellwig <hch@lst.de> --- 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 209fdd8939fba6..ac008345050010 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 8e86b598316c10..8ab043c911f233 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; }
--
2.26.2