return -ENOMEM;
 }
 
-static int snap_by_name(struct rbd_image_header *header, const char *snap_name,
-                       u64 *seq, u64 *size)
+static int snap_by_name(struct rbd_device *rbd_dev, const char *snap_name)
 {
        int i;
+       struct rbd_image_header *header = &rbd_dev->header;
        char *p = header->snap_names;
 
        rbd_assert(header->snapc != NULL);
 
                        /* Found it.  Pass back its id and/or size */
 
-                       if (seq)
-                               *seq = header->snapc->snaps[i];
-                       if (size)
-                               *size = header->snap_sizes[i];
+                       rbd_dev->mapping.snap_id = header->snapc->snaps[i];
+                       rbd_dev->mapping.size = header->snap_sizes[i];
+
                        return i;
                }
                p += strlen(p) + 1;     /* Skip ahead to the next name */
                rbd_dev->mapping.snap_exists = false;
                rbd_dev->mapping.read_only = rbd_dev->rbd_opts.read_only;
        } else {
-               ret = snap_by_name(&rbd_dev->header, snap_name,
-                                       &rbd_dev->mapping.snap_id,
-                                       &rbd_dev->mapping.size);
+               ret = snap_by_name(rbd_dev, snap_name);
                if (ret < 0)
                        goto done;
                rbd_dev->mapping.snap_exists = true;