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| author | Dennis Zhou (Facebook) <dennisszhou@gmail.com> | 2018-09-11 14:41:27 -0400 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-09-21 20:29:03 -0600 |
| commit | 49f4c2dc2b5066e9211101c59cc0828e81d41614 (patch) | |
| tree | 217391585a20535d3c2606d98659786bf73682e2 /include | |
| parent | 27e6fa996c534c32702aa4d32db0ffa383acd050 (diff) | |
| download | linux-49f4c2dc2b5066e9211101c59cc0828e81d41614.tar.gz linux-49f4c2dc2b5066e9211101c59cc0828e81d41614.tar.bz2 linux-49f4c2dc2b5066e9211101c59cc0828e81d41614.zip | |
blkcg: update blkg_lookup_create to do locking
To know when to create a blkg, the general pattern is to do a
blkg_lookup and if that fails, lock and then do a lookup again and if
that fails finally create. It doesn't make much sense for everyone who
wants to do creation to write this themselves.
This changes blkg_lookup_create to do locking and implement this
pattern. The old blkg_lookup_create is renamed to __blkg_lookup_create.
If a call site wants to do its own error handling or already owns the
queue lock, they can use __blkg_lookup_create. This will be used in
upcoming patches.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blk-cgroup.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 24067a1f8b36..cc0f238530f6 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -184,6 +184,8 @@ extern struct cgroup_subsys_state * const blkcg_root_css; struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg, struct request_queue *q, bool update_hint); +struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg, + struct request_queue *q); struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, struct request_queue *q); int blkcg_init_queue(struct request_queue *q); @@ -897,7 +899,7 @@ static inline bool blkcg_bio_issue_check(struct request_queue *q, blkg = blkg_lookup(blkcg, q); if (unlikely(!blkg)) { spin_lock_irq(q->queue_lock); - blkg = blkg_lookup_create(blkcg, q); + blkg = __blkg_lookup_create(blkcg, q); if (IS_ERR(blkg)) blkg = NULL; spin_unlock_irq(q->queue_lock); |