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>

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index b6114d672413004273b91cf743e0b872f899245c..60e75130a44c695b5fe565a6679963961d1b8a3c 100644 (file)
--- 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;
        }