2 files changed, 27 insertions, 2 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index f05f2303a8b8..699f371b9f12 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -106,8 +106,10 @@ static struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
                         return NULL;
 
                 t = atomic_cmpxchg(&sd->s_active, v, v + 1);
-                if (likely(t == v))
+                if (likely(t == v)) {
+                        rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
                         return sd;
+                }
                 if (t < 0)
                         return NULL;
 
@@ -130,6 +132,7 @@ static void sysfs_put_active(struct sysfs_dirent *sd)
         if (unlikely(!sd))
                 return;
 
+        rwsem_release(&sd->dep_map, 1, _RET_IP_);
         v = atomic_dec_return(&sd->s_active);
         if (likely(v != SD_DEACTIVATED_BIAS))
                 return;
@@ -194,15 +197,21 @@ static void sysfs_deactivate(struct sysfs_dirent *sd)
         BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
         sd->s_sibling = (void *)&wait;
 
+        rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
         /* atomic_add_return() is a mb(), put_active() will always see
          * the updated sd->s_sibling.
          */
         v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
 
-        if (v != SD_DEACTIVATED_BIAS)
+        if (v != SD_DEACTIVATED_BIAS) {
+                lock_contended(&sd->dep_map, _RET_IP_);
                 wait_for_completion(&wait);
+        }
 
         sd->s_sibling = NULL;
+
+        lock_acquired(&sd->dep_map, _RET_IP_);
+        rwsem_release(&sd->dep_map, 1, _RET_IP_);
 }
 
 static int sysfs_alloc_ino(ino_t *pino)
@@ -345,6 +354,7 @@ struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
 
         atomic_set(&sd->s_count, 1);
         atomic_set(&sd->s_active, 0);
+        sysfs_dirent_init_lockdep(sd);
 
         sd->s_name = name;
         sd->s_mode = mode;
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index ca52e7b9d8f8..cdd9377a6e06 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -8,6 +8,7 @@
  * This file is released under the GPLv2.
  */
 
+#include <linux/lockdep.h>
 #include <linux/fs.h>
 
 struct sysfs_open_dirent;
@@ -50,6 +51,9 @@ struct sysfs_inode_attrs {
 struct sysfs_dirent {
         atomic_t                s_count;
         atomic_t                s_active;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+        struct lockdep_map      dep_map;
+#endif
         struct sysfs_dirent     *s_parent;
         struct sysfs_dirent     *s_sibling;
         const char              *s_name;
@@ -84,6 +88,17 @@ static inline unsigned int sysfs_type(struct sysfs_dirent *sd)
         return sd->s_flags & SYSFS_TYPE_MASK;
 }
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#define sysfs_dirent_init_lockdep(sd)                           \
+do {                                                            \
+        static struct lock_class_key __key;                     \
+                                                                \
+        lockdep_init_map(&sd->dep_map, "s_active", &__key, 0);  \
+} while(0)
+#else
+#define sysfs_dirent_init_lockdep(sd) do {} while(0)
+#endif
+
 /*
  * Context structure to be used while adding/removing nodes.
  */