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authorTejun Heo <tj@kernel.org>2012-03-05 13:15:11 -0800
committerJens Axboe <axboe@kernel.dk>2012-03-06 21:27:23 +0100
commit7ee9c5620504906e98451dc9a1945b2b9e892cb8 (patch)
tree1daf4d9fc8d03ebbc88ceedb7abeec46d8c71df3 /block/cfq-iosched.c
parent92616b5b3a7c7fa8148df82e7ff6183056f2bfc8 (diff)
downloadlinux-7ee9c5620504906e98451dc9a1945b2b9e892cb8.tar.gz
blkcg: let blkio_group point to blkio_cgroup directly
Currently, blkg points to the associated blkcg via its css_id.  This
unnecessarily complicates dereferencing blkcg.  Let blkg hold a
reference to the associated blkcg and point directly to it and disable
css_id on blkio_subsys.

This change requires splitting blkiocg_destroy() into
blkiocg_pre_destroy() and blkiocg_destroy() so that all blkg's can be
destroyed and all the blkcg references held by them dropped during
cgroup removal.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/cfq-iosched.c')
-rw-r--r--block/cfq-iosched.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index f67d109eb974..9ef86fbfc9ae 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1133,6 +1133,10 @@ static void cfq_put_cfqg(struct cfq_group *cfqg)
 	cfqg->ref--;
 	if (cfqg->ref)
 		return;
+
+	/* release the extra blkcg reference this blkg has been holding */
+	css_put(&cfqg->blkg.blkcg->css);
+
 	for_each_cfqg_st(cfqg, i, j, st)
 		BUG_ON(!RB_EMPTY_ROOT(&st->rb));
 	free_percpu(cfqg->blkg.stats_cpu);