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authorOleg Nesterov <oleg@redhat.com>2015-07-22 21:21:13 +0300
committerOleg Nesterov <oleg@redhat.com>2015-08-15 14:52:11 +0300
commit853b39a7c82826b8413048feec7bf08e98ce7a84 (patch)
tree459b6afcc9d478a4beb6347627cc13da2e24b132 /fs/super.c
parentbf3eac84c42da7017610abc8cfba64921ea92c76 (diff)
downloadlinux-853b39a7c82826b8413048feec7bf08e98ce7a84.tar.xz
shift percpu_counter_destroy() into destroy_super_work()
Of course, this patch is ugly as hell. It will be (partially) reverted later. We add it to ensure that other WIP changes in percpu_rw_semaphore won't break fs/super.c. We do not even need this change right now, percpu_free_rwsem() is fine in atomic context. But we are going to change this, it will be might_sleep() after we merge the rcu_sync() patches. And even after that we do not really need destroy_super_work(), we will kill it in any case. Instead, destroy_super_rcu() should just check that rss->cb_state == CB_IDLE and do call_rcu() again in the (very unlikely) case this is not true. So this is just the temporary kludge which helps us to avoid the conflicts with the changes which will be (hopefully) routed via rcu tree. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jan Kara <jack@suse.com>
Diffstat (limited to 'fs/super.c')
-rw-r--r--fs/super.c23
1 files changed, 19 insertions, 4 deletions
diff --git a/fs/super.c b/fs/super.c
index 8aa3cbc571d1..c937bd7b4d33 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -135,6 +135,24 @@ static unsigned long super_cache_count(struct shrinker *shrink,
return total_objects;
}
+static void destroy_super_work(struct work_struct *work)
+{
+ struct super_block *s = container_of(work, struct super_block,
+ destroy_work);
+ int i;
+
+ for (i = 0; i < SB_FREEZE_LEVELS; i++)
+ percpu_counter_destroy(&s->s_writers.counter[i]);
+ kfree(s);
+}
+
+static void destroy_super_rcu(struct rcu_head *head)
+{
+ struct super_block *s = container_of(head, struct super_block, rcu);
+ INIT_WORK(&s->destroy_work, destroy_super_work);
+ schedule_work(&s->destroy_work);
+}
+
/**
* destroy_super - frees a superblock
* @s: superblock to free
@@ -143,16 +161,13 @@ static unsigned long super_cache_count(struct shrinker *shrink,
*/
static void destroy_super(struct super_block *s)
{
- int i;
list_lru_destroy(&s->s_dentry_lru);
list_lru_destroy(&s->s_inode_lru);
- for (i = 0; i < SB_FREEZE_LEVELS; i++)
- percpu_counter_destroy(&s->s_writers.counter[i]);
security_sb_free(s);
WARN_ON(!list_empty(&s->s_mounts));
kfree(s->s_subtype);
kfree(s->s_options);
- kfree_rcu(s, rcu);
+ call_rcu(&s->rcu, destroy_super_rcu);
}
/**