[PATCH 02/11] blkcg: __blkg_lookup_create() doesn't have to fail on radix tree preload failure

Tejun Heo
2012-04-26T21:59:45Z

__blkg_lookup_create() currently fails if radix_tree_preload() fails;
however, preload failrue doesn't imply insertion failure. Don't fail
__blkg_lookup_create() on preload failure.

While at it, drop sparse locking annotation which no longer applies.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
block/blk-cgroup.c | 13 +++++--------
1 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 4ab7420..197fb50 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -177,9 +177,9 @@ EXPORT_SYMBOL_GPL(blkg_lookup);

static struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg,
struct request_queue *q)
- __releases(q->queue_lock) __acquires(q->queue_lock)
{
struct blkcg_gq *blkg;
+ bool preloaded;
int ret;

WARN_ON_ONCE(!rcu_read_lock_held());
@@ -203,9 +203,7 @@ static struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg,
goto err_put;

/* insert */
- ret = radix_tree_preload(GFP_ATOMIC);
- if (ret)
- goto err_free;
+ preloaded = !radix_tree_preload(GFP_ATOMIC);

spin_lock(&blkcg->lock);
ret = radix_tree_insert(&blkcg->blkg_tree, q->id, blkg);
@@ -215,14 +213,13 @@ static struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg,
}
spin_unlock(&blkcg->lock);

- radix_tree_preload_end();
-
+ if (preloaded)
+ radix_tree_preload_end();
if (!ret)
return blkg;
-err_free:
- blkg_free(blkg);
err_put:
css_put(&blkcg->css);
+ blkg_free(blkg);
return ERR_PTR(ret);
}

--
1.7.7.3