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-rw-r--r--mm/cleancache.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/mm/cleancache.c b/mm/cleancache.c
index 532495f2e4f4..aa10f9a3bc88 100644
--- a/mm/cleancache.c
+++ b/mm/cleancache.c
@@ -106,15 +106,17 @@ static DEFINE_MUTEX(poolid_mutex);
*/
/*
- * Register operations for cleancache, returning previous thus allowing
- * detection of multiple backends and possible nesting.
+ * Register operations for cleancache. Returns 0 on success.
*/
-struct cleancache_ops *cleancache_register_ops(struct cleancache_ops *ops)
+int cleancache_register_ops(struct cleancache_ops *ops)
{
- struct cleancache_ops *old = cleancache_ops;
int i;
mutex_lock(&poolid_mutex);
+ if (cleancache_ops) {
+ mutex_unlock(&poolid_mutex);
+ return -EBUSY;
+ }
for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
if (fs_poolid_map[i] == FS_NO_BACKEND)
fs_poolid_map[i] = ops->init_fs(PAGE_SIZE);
@@ -130,7 +132,7 @@ struct cleancache_ops *cleancache_register_ops(struct cleancache_ops *ops)
barrier();
cleancache_ops = ops;
mutex_unlock(&poolid_mutex);
- return old;
+ return 0;
}
EXPORT_SYMBOL(cleancache_register_ops);