[PATCH 2/4] btrfs: define the AUTO_K(V)FREE_PTR helper macros

["Miquel Sabaté Solà" <mssola@mssola.com>]

These are two simple macros which ensure that a pointer is initialized
to NULL and with the proper cleanup attribute for it.

Suggested-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>
---
 fs/btrfs/misc.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/btrfs/misc.h b/fs/btrfs/misc.h
index 60f9b000d644..0e33327e70d9 100644
--- a/fs/btrfs/misc.h
+++ b/fs/btrfs/misc.h
@@ -13,6 +13,13 @@
 #include <linux/rbtree.h>
 #include <linux/bio.h>
 
+/*
+ * Convenient macros to define a pointer with the __free(kfree) and
+ * __free(kvfree) cleanup attributes and initialized to NULL.
+ */
+#define AUTO_KFREE_PTR(name)       *name __free(kfree) = NULL
+#define AUTO_KVFREE_PTR(name)      *name __free(kvfree) = NULL
+
 /*
  * Enumerate bits using enum autoincrement. Define the @name as the n-th bit.
  */
-- 
2.51.1