bcache: add mutex lock for bch_is_open

Since bch_is_open will iterate linked list bch_cache_sets and
uncached_devices, it needs bch_register_lock.

Signed-off-by: Jianjian Huo <samuel.huo@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index b6114d672413..60e75130a44c 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1966,10 +1966,12 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
         if (IS_ERR(bdev)) {
                 if (bdev == ERR_PTR(-EBUSY)) {
                         bdev = lookup_bdev(strim(path));
+                        mutex_lock(&bch_register_lock);
                         if (!IS_ERR(bdev) && bch_is_open(bdev))
                                 err = "device already registered";
                         else
                                 err = "device busy";
+                        mutex_unlock(&bch_register_lock);
                 }
                 goto err;
         }