ext4: fix up rb_root initializations to use RB_ROOT

ext4 uses rb_node = NULL; to zero rb_root at few places.  Using
RB_ROOT as the initializer is more portable in case the underlying
implementation of rbtrees changes in the future.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Eric Paris <eparis@redhat.com>

3 files changed, 4 insertions, 4 deletions

diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
index a60ab9aad57d..983f0e127493 100644
--- a/fs/ext4/block_validity.c
+++ b/fs/ext4/block_validity.c
@@ -205,14 +205,14 @@ void ext4_release_system_zone(struct super_block *sb)
                 entry = rb_entry(n, struct ext4_system_zone, node);
                 kmem_cache_free(ext4_system_zone_cachep, entry);
                 if (!parent)
-                        EXT4_SB(sb)->system_blks.rb_node = NULL;
+                        EXT4_SB(sb)->system_blks = RB_ROOT;
                 else if (parent->rb_left == n)
                         parent->rb_left = NULL;
                 else if (parent->rb_right == n)
                         parent->rb_right = NULL;
                 n = parent;
         }
-        EXT4_SB(sb)->system_blks.rb_node = NULL;
+        EXT4_SB(sb)->system_blks = RB_ROOT;
 }
 
 /*
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 29857ddd9e26..86cb6d86a048 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -305,7 +305,7 @@ static void free_rb_tree_fname(struct rb_root *root)
                         kfree(old);
                 }
                 if (!parent)
-                        root->rb_node = NULL;
+                        *root = RB_ROOT;
                 else if (parent->rb_left == n)
                         parent->rb_left = NULL;
                 else if (parent->rb_right == n)
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 37d2438e0cb4..abb11e328b65 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2253,7 +2253,7 @@ int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
 
         INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
         init_rwsem(&meta_group_info[i]->alloc_sem);
-        meta_group_info[i]->bb_free_root.rb_node = NULL;
+        meta_group_info[i]->bb_free_root = RB_ROOT;
 
 #ifdef DOUBLE_CHECK
         {