block: make block cgroup policies follow bio task association

Implement bio_blkio_cgroup() which returns the blkcg associated with
the bio if exists or %current's blkcg, and use it in blk-throttle and
cfq-iosched propio.  This makes both cgroup policies honor task
association for the bio instead of always assuming %current.

As nobody is using bio_set_task() yet, this doesn't introduce any
behavior change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 2 insertions, 2 deletions

diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 66eaefefcbd2..98cd8533378f 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -379,7 +379,7 @@ static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg,
 #ifdef CONFIG_BLK_CGROUP
 extern struct blkio_cgroup blkio_root_cgroup;
 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
-extern struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk);
+extern struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio);
 extern struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
                                        struct request_queue *q);
 struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
@@ -413,7 +413,7 @@ struct cgroup;
 static inline struct blkio_cgroup *
 cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
 static inline struct blkio_cgroup *
-task_blkio_cgroup(struct task_struct *tsk) { return NULL; }
+bio_blkio_cgroup(struct bio *bio) { return NULL; }
 
 static inline struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
                                               void *key) { return NULL; }