From: Milan Broz <mbroz@redhat.com>

Allow NULL buffer in dm_copy_name_and_uuid if you only want to return one of
the fields.

(Required by a following patch that adds these fields to sysfs.)

Signed-off-by: Milan Broz <mbroz@redhat.com>
Reviewed-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
---
 drivers/md/dm-ioctl.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

Index: linux-2.6.28/drivers/md/dm-ioctl.c
===================================================================
--- linux-2.6.28.orig/drivers/md/dm-ioctl.c	2009-01-05 17:40:34.000000000 +0000
+++ linux-2.6.28/drivers/md/dm-ioctl.c	2009-01-05 18:18:24.000000000 +0000
@@ -1550,8 +1550,10 @@ int dm_copy_name_and_uuid(struct mapped_
 		goto out;
 	}
 
-	strcpy(name, hc->name);
-	strcpy(uuid, hc->uuid ? : "");
+	if (name)
+		strcpy(name, hc->name);
+	if (uuid)
+		strcpy(uuid, hc->uuid ? : "");
 
 out:
 	up_read(&_hash_lock);