blkcg: rename blkg_try_get to blkg_tryget

blkg reference counting now uses percpu_ref rather than atomic_t. Let's
make this consistent with css_tryget. This renames blkg_try_get to
blkg_tryget and now returns a bool rather than the blkg or NULL.

Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bio.c b/block/bio.c
index c39251e..1cd47f2 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -1974,7 +1974,7 @@ int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg)
 {
        if (unlikely(bio->bi_blkg))
                return -EBUSY;
-       bio->bi_blkg = blkg_try_get_closest(blkg);
+       bio->bi_blkg = blkg_tryget_closest(blkg);
        return 0;
 }
 

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index ab3676e..76136be 100644 (file)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1794,8 +1794,7 @@ void blkcg_maybe_throttle_current(void)
        blkg = blkg_lookup(blkcg, q);
        if (!blkg)
                goto out;
-       blkg = blkg_try_get(blkg);
-       if (!blkg)
+       if (!blkg_tryget(blkg))
                goto out;
        rcu_read_unlock();
 

diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 2d848b2..27c14f8 100644 (file)
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -625,7 +625,7 @@ static void blkiolatency_timer_fn(struct timer_list *t)
                 * We could be exiting, don't access the pd unless we have a
                 * ref on the blkg.
                 */
-               if (!blkg_try_get(blkg))
+               if (!blkg_tryget(blkg))
                        continue;
 
                iolat = blkg_to_lat(blkg);

diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 7ff5d8b..b7fd080 100644 (file)
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -494,27 +494,25 @@ static inline void blkg_get(struct blkcg_gq *blkg)
 }
 
 /**
- * blkg_try_get - try and get a blkg reference
+ * blkg_tryget - try and get a blkg reference
  * @blkg: blkg to get
  *
  * This is for use when doing an RCU lookup of the blkg.  We may be in the midst
  * of freeing this blkg, so we can only use it if the refcnt is not zero.
  */
-static inline struct blkcg_gq *blkg_try_get(struct blkcg_gq *blkg)
+static inline bool blkg_tryget(struct blkcg_gq *blkg)
 {
-       if (percpu_ref_tryget(&blkg->refcnt))
-               return blkg;
-       return NULL;
+       return percpu_ref_tryget(&blkg->refcnt);
 }
 
 /**
- * blkg_try_get_closest - try and get a blkg ref on the closet blkg
+ * blkg_tryget_closest - try and get a blkg ref on the closet blkg
  * @blkg: blkg to get
  *
  * This walks up the blkg tree to find the closest non-dying blkg and returns
  * the blkg that it did association with as it may not be the passed in blkg.
  */
-static inline struct blkcg_gq *blkg_try_get_closest(struct blkcg_gq *blkg)
+static inline struct blkcg_gq *blkg_tryget_closest(struct blkcg_gq *blkg)
 {
        while (!percpu_ref_tryget(&blkg->refcnt))
                blkg = blkg->parent;
@@ -599,7 +597,7 @@ static inline struct request_list *blk_get_rl(struct request_queue *q,
        if (unlikely(!blkg))
                blkg = __blkg_lookup_create(blkcg, q);
 
-       if (!blkg_try_get(blkg))
+       if (!blkg_tryget(blkg))
                goto rl_use_root;
 
        rcu_read_unlock();