uuid: Add inline helpers to import / export UUIDs

Sometimes we may need to import UUID from or export to the raw buffer,
which is provided outside of kernel and can't be declared as UUID type.
With current API this operation will require an explicit casting
to one of UUID types and length, that is always a constant derived as sizeof
the certain UUID type.

Provide a helpful set of inline helpers to minimize developer's effort
in the cases when raw buffers are involved.
Suggested-by: David Sterba <dsterba@suse.cz>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David Sterba <dsterba@suse.com>

include/linux/uuid.h

@@ -43,6 +43,16 @@ static inline void guid_copy(guid_t *dst, const guid_t *src)
 	memcpy(dst, src, sizeof(guid_t));
 }
 
+static inline void import_guid(guid_t *dst, const __u8 *src)
+{
+	memcpy(dst, src, sizeof(guid_t));
+}
+
+static inline void export_guid(__u8 *dst, const guid_t *src)
+{
+	memcpy(dst, src, sizeof(guid_t));
+}
+
 static inline bool guid_is_null(const guid_t *guid)
 {
 	return guid_equal(guid, &guid_null);
@@ -58,6 +68,16 @@ static inline void uuid_copy(uuid_t *dst, const uuid_t *src)
 	memcpy(dst, src, sizeof(uuid_t));
 }
 
+static inline void import_uuid(uuid_t *dst, const __u8 *src)
+{
+	memcpy(dst, src, sizeof(uuid_t));
+}
+
+static inline void export_uuid(__u8 *dst, const uuid_t *src)
+{
+	memcpy(dst, src, sizeof(uuid_t));
+}
+
 static inline bool uuid_is_null(const uuid_t *uuid)
 {
 	return uuid_equal(uuid, &uuid_null);