1 files changed, 14 insertions, 2 deletions

diff --git a/lib/idr.c b/lib/idr.c
index 305117ca2d41..7b5a59caa989 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -100,10 +100,11 @@ static int sub_alloc(struct idr *idp, void *ptr, int *starting_id)
         int n, m, sh;
         struct idr_layer *p, *new;
         struct idr_layer *pa[MAX_LEVEL];
-        int l, id;
+        int l, id, oid;
         long bm;
 
         id = *starting_id;
+ restart:
         p = idp->top;
         l = idp->layers;
         pa[l--] = NULL;
@@ -117,12 +118,23 @@ static int sub_alloc(struct idr *idp, void *ptr, int *starting_id)
                 if (m == IDR_SIZE) {
                         /* no space available go back to previous layer. */
                         l++;
+                        oid = id;
                         id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1;
+
+                        /* if already at the top layer, we need to grow */
                         if (!(p = pa[l])) {
                                 *starting_id = id;
                                 return -2;
                         }
-                        continue;
+
+                        /* If we need to go up one layer, continue the
+                         * loop; otherwise, restart from the top.
+                         */
+                        sh = IDR_BITS * (l + 1);
+                        if (oid >> sh == id >> sh)
+                                continue;
+                        else
+                                goto restart;
                 }
                 if (m != n) {
                         sh = IDR_BITS*l;