radix-tree: Chain preallocated nodes through ->parent

Chaining through the ->private_data member means we have to zero
->private_data after removing preallocated nodes from the list.
We're about to initialise ->parent anyway, so we can avoid zeroing it.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>

2 files changed, 7 insertions, 8 deletions

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 14130ab197c0..66c71312c381 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -82,7 +82,7 @@ static struct kmem_cache *radix_tree_node_cachep;
  */
 struct radix_tree_preload {
         unsigned nr;
-        /* nodes->private_data points to next preallocated node */
+        /* nodes->parent points to next preallocated node */
         struct radix_tree_node *nodes;
 };
 static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
@@ -405,8 +405,7 @@ radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent,
                 rtp = this_cpu_ptr(&radix_tree_preloads);
                 if (rtp->nr) {
                         ret = rtp->nodes;
-                        rtp->nodes = ret->private_data;
-                        ret->private_data = NULL;
+                        rtp->nodes = ret->parent;
                         rtp->nr--;
                 }
                 /*
@@ -483,7 +482,7 @@ static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr)
                 preempt_disable();
                 rtp = this_cpu_ptr(&radix_tree_preloads);
                 if (rtp->nr < nr) {
-                        node->private_data = rtp->nodes;
+                        node->parent = rtp->nodes;
                         rtp->nodes = node;
                         rtp->nr++;
                 } else {
@@ -2260,7 +2259,7 @@ static int radix_tree_cpu_dead(unsigned int cpu)
         rtp = &per_cpu(radix_tree_preloads, cpu);
         while (rtp->nr) {
                 node = rtp->nodes;
-                rtp->nodes = node->private_data;
+                rtp->nodes = node->parent;
                 kmem_cache_free(radix_tree_node_cachep, node);
                 rtp->nr--;
         }
diff --git a/tools/testing/radix-tree/linux.c b/tools/testing/radix-tree/linux.c
index 94bcdb992bbf..cf48c8473f48 100644
--- a/tools/testing/radix-tree/linux.c
+++ b/tools/testing/radix-tree/linux.c
@@ -35,9 +35,9 @@ void *kmem_cache_alloc(struct kmem_cache *cachep, int flags)
         if (cachep->nr_objs) {
                 cachep->nr_objs--;
                 node = cachep->objs;
-                cachep->objs = node->private_data;
+                cachep->objs = node->parent;
                 pthread_mutex_unlock(&cachep->lock);
-                node->private_data = NULL;
+                node->parent = NULL;
         } else {
                 pthread_mutex_unlock(&cachep->lock);
                 node = malloc(cachep->size);
@@ -64,7 +64,7 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)
         } else {
                 struct radix_tree_node *node = objp;
                 cachep->nr_objs++;
-                node->private_data = cachep->objs;
+                node->parent = cachep->objs;
                 cachep->objs = node;
         }
         pthread_mutex_unlock(&cachep->lock);