2 files changed, 13 insertions, 0 deletions

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 6dd31a291d84..949c71fbfbb5 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -201,6 +201,14 @@ config BLK_DEV_DM
 
           If unsure, say N.
 
+config DM_DEBUG
+        boolean "Device mapper debugging support"
+        depends on BLK_DEV_DM && EXPERIMENTAL
+        ---help---
+          Enable this for messages that may help debug device-mapper problems.
+
+          If unsure, say N.
+
 config DM_CRYPT
         tristate "Crypt target support"
         depends on BLK_DEV_DM && EXPERIMENTAL
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 3c03c0ecab7e..fe701c4834fe 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -21,6 +21,11 @@
 #define DMERR(f, arg...) printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
 #define DMWARN(f, arg...) printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
 #define DMINFO(f, arg...) printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
+#ifdef CONFIG_DM_DEBUG
+#  define DMDEBUG(f, arg...) printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
+#else
+#  define DMDEBUG(f, arg...) do {} while (0)
+#endif
 
 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
                           0 : scnprintf(result + sz, maxlen - sz, x))