bcache: Fix a lockdep splat in an error path

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index c70521fe57a6..5136e11eadb0 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1873,7 +1873,10 @@ static void register_cache(struct cache_sb *sb, struct page *sb_page,
         if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache"))
                 goto err;
 
+        mutex_lock(&bch_register_lock);
         err = register_cache_set(ca);
+        mutex_unlock(&bch_register_lock);
+
         if (err)
                 goto err;
 
@@ -1935,8 +1938,6 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
         if (!try_module_get(THIS_MODULE))
                 return -EBUSY;
 
-        mutex_lock(&bch_register_lock);
-
         if (!(path = kstrndup(buffer, size, GFP_KERNEL)) ||
             !(sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL)))
                 goto err;
@@ -1969,7 +1970,9 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
                 if (!dc)
                         goto err_close;
 
+                mutex_lock(&bch_register_lock);
                 register_bdev(sb, sb_page, bdev, dc);
+                mutex_unlock(&bch_register_lock);
         } else {
                 struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
                 if (!ca)
@@ -1982,7 +1985,6 @@ out:
                 put_page(sb_page);
         kfree(sb);
         kfree(path);
-        mutex_unlock(&bch_register_lock);
         module_put(THIS_MODULE);
         return ret;