Make mempool optional in dm_split_lvm_name()

2 files changed, 3 insertions, 1 deletions

diff --git a/libdm/libdevmapper.h b/libdm/libdevmapper.h
index a6e253008..c8ce21f64 100644
--- a/libdm/libdevmapper.h
+++ b/libdm/libdevmapper.h
@@ -819,6 +819,8 @@ int dm_set_selinux_context(const char *path, mode_t mode);
 /*
  * Break up the name of a mapped device into its constituent
  * Volume Group, Logical Volume and Layer (if present).
+ * If mem is supplied, the result is allocated from the mempool.
+ * Otherwise the strings are changed in situ.
  */
 int dm_split_lvm_name(struct dm_pool *mem, const char *dmname,
 		      char **vgname, char **lvname, char **layer);
diff --git a/libdm/libdm-string.c b/libdm/libdm-string.c
index 0e41f9d9d..c6f101bcc 100644
--- a/libdm/libdm-string.c
+++ b/libdm/libdm-string.c
@@ -93,7 +93,7 @@ static char *_unquote(char *component)
 int dm_split_lvm_name(struct dm_pool *mem, const char *dmname,
 		      char **vgname, char **lvname, char **layer)
 {
-	if (!(*vgname = dm_pool_strdup(mem, dmname)))
+	if (mem && !(*vgname = dm_pool_strdup(mem, dmname)))
 		return 0;
 
 	_unquote(*layer = _unquote(*lvname = _unquote(*vgname)));