1 files changed, 12 insertions, 4 deletions

diff --git a/lib/idr.c b/lib/idr.c
index d226259c3c28..de19030a999b 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -48,15 +48,21 @@ static struct idr_layer *alloc_layer(struct idr *idp)
         return(p);
 }
 
+/* only called when idp->lock is held */
+static void __free_layer(struct idr *idp, struct idr_layer *p)
+{
+        p->ary[0] = idp->id_free;
+        idp->id_free = p;
+        idp->id_free_cnt++;
+}
+
 static void free_layer(struct idr *idp, struct idr_layer *p)
 {
         /*
          * Depends on the return element being zeroed.
          */
         spin_lock(&idp->lock);
-        p->ary[0] = idp->id_free;
-        idp->id_free = p;
-        idp->id_free_cnt++;
+        __free_layer(idp, p);
         spin_unlock(&idp->lock);
 }
 
@@ -184,12 +190,14 @@ build_up:
                          * The allocation failed.  If we built part of
                          * the structure tear it down.
                          */
+                        spin_lock(&idp->lock);
                         for (new = p; p && p != idp->top; new = p) {
                                 p = p->ary[0];
                                 new->ary[0] = NULL;
                                 new->bitmap = new->count = 0;
-                                free_layer(idp, new);
+                                __free_layer(idp, new);
                         }
+                        spin_unlock(&idp->lock);
                         return -1;
                 }
                 new->ary[0] = p;