1 files changed, 47 insertions, 1 deletions

diff --git a/lib/idr.c b/lib/idr.c
index c11c5765cdef..80ca9aca038b 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -449,6 +449,7 @@ void idr_remove_all(struct idr *idp)
 
         n = idp->layers * IDR_BITS;
         p = idp->top;
+        rcu_assign_pointer(idp->top, NULL);
         max = 1 << n;
 
         id = 0;
@@ -467,7 +468,6 @@ void idr_remove_all(struct idr *idp)
                         p = *--paa;
                 }
         }
-        rcu_assign_pointer(idp->top, NULL);
         idp->layers = 0;
 }
 EXPORT_SYMBOL(idr_remove_all);
@@ -579,6 +579,52 @@ int idr_for_each(struct idr *idp,
 EXPORT_SYMBOL(idr_for_each);
 
 /**
+ * idr_get_next - lookup next object of id to given id.
+ * @idp: idr handle
+ * @id:  pointer to lookup key
+ *
+ * Returns pointer to registered object with id, which is next number to
+ * given id.
+ */
+
+void *idr_get_next(struct idr *idp, int *nextidp)
+{
+        struct idr_layer *p, *pa[MAX_LEVEL];
+        struct idr_layer **paa = &pa[0];
+        int id = *nextidp;
+        int n, max;
+
+        /* find first ent */
+        n = idp->layers * IDR_BITS;
+        max = 1 << n;
+        p = rcu_dereference(idp->top);
+        if (!p)
+                return NULL;
+
+        while (id < max) {
+                while (n > 0 && p) {
+                        n -= IDR_BITS;
+                        *paa++ = p;
+                        p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]);
+                }
+
+                if (p) {
+                        *nextidp = id;
+                        return p;
+                }
+
+                id += 1 << n;
+                while (n < fls(id)) {
+                        n += IDR_BITS;
+                        p = *--paa;
+                }
+        }
+        return NULL;
+}
+
+
+
+/**
  * idr_replace - replace pointer for given id
  * @idp: idr handle
  * @ptr: pointer you want associated with the id