osd/OSDMap: make get prev/next up osd more efficient

what's more, in get_previous_up_osd_before(), if arg n = 0, run into endless loop Signed-off-by: Mingxin Liu <mingxin@xsky.com>
ceph · Jan 18, 2017 · a37765c · a37765c
1 parent a7b7862
commit a37765c
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/src/osd/OSDMap.h b/src/osd/OSDMap.h
@@ -525,6 +525,8 @@ class OSDMap {
   }
 
   int get_next_up_osd_after(int n) const {
+    if (get_max_osd() == 0)
+      return -1;
     for (int i = n + 1; i != n; ++i) {
       if (i >= get_max_osd())
 	i = 0;
@@ -537,6 +539,8 @@ class OSDMap {
   }
 
   int get_previous_up_osd_before(int n) const {
+    if (get_max_osd() == 0)
+      return -1;
     for (int i = n - 1; i != n; --i) {
       if (i < 0)
 	i = get_max_osd() - 1;