return ERR_PTR(err);
 }
 
-/*
- * rbtree of pg_mapping for handling pg_temp (explicit mapping of pgid
- * to a set of osds) and primary_temp (explicit primary setting)
- */
-static int pgid_cmp(struct ceph_pg l, struct ceph_pg r)
+int ceph_pg_compare(const struct ceph_pg *lhs, const struct ceph_pg *rhs)
 {
-       if (l.pool < r.pool)
+       if (lhs->pool < rhs->pool)
                return -1;
-       if (l.pool > r.pool)
+       if (lhs->pool > rhs->pool)
                return 1;
-       if (l.seed < r.seed)
+       if (lhs->seed < rhs->seed)
                return -1;
-       if (l.seed > r.seed)
+       if (lhs->seed > rhs->seed)
                return 1;
+
        return 0;
 }
 
+/*
+ * rbtree of pg_mapping for handling pg_temp (explicit mapping of pgid
+ * to a set of osds) and primary_temp (explicit primary setting)
+ */
 static int __insert_pg_mapping(struct ceph_pg_mapping *new,
                               struct rb_root *root)
 {
        while (*p) {
                parent = *p;
                pg = rb_entry(parent, struct ceph_pg_mapping, node);
-               c = pgid_cmp(new->pgid, pg->pgid);
+               c = ceph_pg_compare(&new->pgid, &pg->pgid);
                if (c < 0)
                        p = &(*p)->rb_left;
                else if (c > 0)
 
        while (n) {
                pg = rb_entry(n, struct ceph_pg_mapping, node);
-               c = pgid_cmp(pgid, pg->pgid);
+               c = ceph_pg_compare(&pgid, &pg->pgid);
                if (c < 0) {
                        n = n->rb_left;
                } else if (c > 0) {