[PATCH 14/15] blkcg: rename blkg_try_get to blkg_tryget

Dennis Zhou
2018-08-31T01:53:55Z

From: "Dennis Zhou (Facebook)" <dennisszhou@gmail.com>

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>
---
block/bio.c | 2 +-
block/blk-cgroup.c | 3 +--
block/blk-iolatency.c | 2 +-
include/linux/blk-cgroup.h | 10 ++++------
4 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index b792bffecce1..a0b816811e7d 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1943,7 +1943,7 @@ int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg)
{
if (unlikely(bio->bi_blkg))
return -EBUSY;
- if (!blkg_try_get(blkg))
+ if (!blkg_tryget(blkg))
return -ENODEV;
bio->bi_blkg = blkg;
return 0;
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index bbea4b44bd8f..1eaf097e38b0 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1777,8 +1777,7 @@ 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 9d7052bad6f7..5a4cec54c998 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -628,7 +628,7 @@ 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 b60d063fb0d7..0134cdd270b8 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -459,17 +459,15 @@ 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);
}

/**
@@ -560,7 +558,7 @@ static inline struct request_list *blk_get_rl(struct request_queue *q,
}
}

- if (blkg_try_get(blkg))
+ if (blkg_tryget(blkg))
break;
cpu_relax();
}
--
2.17.1