Hi Jan,
diff --git a/fs/mbcache.c b/fs/mbcache.c
index d1ebb5df2856..96f1d49d30a5 100644
--- a/fs/mbcache.c
+++ b/fs/mbcache.c
@ -106,21 +106,28 @@ int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
}
}
hlist_bl_add_head(&entry->e_hash_list, head);
- hlist_bl_unlock(head);
-
+ /*
+ * Add entry to LRU list before it can be found by
+ * mb_cache_entry_delete() to avoid races
+ */
spin_lock(&cache->c_list_lock);
list_add_tail(&entry->e_list, &cache->c_list);
- /* Grab ref for LRU list */
- atomic_inc(&entry->e_refcnt);
cache->c_entry_count++;
spin_unlock(&cache->c_list_lock);
+ hlist_bl_unlock(head);
return 0;
}
EXPORT_SYMBOL(mb_cache_entry_create);
The above movement of hlist_bl_unlock() is a problem for RT wrt both
taking and releasing of ->c_list_lock, it becoming an rtmutex in RT and
hlist_bl_unlock() taking a preemption blocking bit spinlock.
Is that scope increase necessary? If so, looks like ->c_list_lock
could probably become a raw_spinlock_t without anyone noticing.
-Mike