[PATCH 7/8] mtd/ubi: use rbtree postorder iteration helper instead of opencoding

[Cody P Schafer]

Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
of opencoding an alternate postorder iteration that modifies the tree

Signed-off-by: Cody P Schafer <cody at linux.vnet.ibm.com>
---
 drivers/mtd/ubi/attach.c | 49 +++++++-----------------------------------------
 drivers/mtd/ubi/wl.c     | 25 +++---------------------
 2 files changed, 10 insertions(+), 64 deletions(-)

diff --git a/drivers/mtd/ubi/attach.c b/drivers/mtd/ubi/attach.c
index c071d41..6de0786 100644
--- a/drivers/mtd/ubi/attach.c
+++ b/drivers/mtd/ubi/attach.c
@@ -1133,27 +1133,11 @@ static int late_analysis(struct ubi_device *ubi, struct ubi_attach_info *ai)
  */
 static void destroy_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av)
 {
-	struct ubi_ainf_peb *aeb;
-	struct rb_node *this = av->root.rb_node;
-
-	while (this) {
-		if (this->rb_left)
-			this = this->rb_left;
-		else if (this->rb_right)
-			this = this->rb_right;
-		else {
-			aeb = rb_entry(this, struct ubi_ainf_peb, u.rb);
-			this = rb_parent(this);
-			if (this) {
-				if (this->rb_left == &aeb->u.rb)
-					this->rb_left = NULL;
-				else
-					this->rb_right = NULL;
-			}
+	struct ubi_ainf_peb *aeb, *next;
+
+	rbtree_postorder_for_each_entry_safe(aeb, next, &av->root, u.rb)
+		kmem_cache_free(ai->aeb_slab_cache, aeb);
 
-			kmem_cache_free(ai->aeb_slab_cache, aeb);
-		}
-	}
 	kfree(av);
 }
 
@@ -1164,8 +1148,7 @@ static void destroy_av(struct ubi_attach_info *ai, struct ubi_ainf_volume *av)
 static void destroy_ai(struct ubi_attach_info *ai)
 {
 	struct ubi_ainf_peb *aeb, *aeb_tmp;
-	struct ubi_ainf_volume *av;
-	struct rb_node *rb;
+	struct ubi_ainf_volume *av, *next;
 
 	list_for_each_entry_safe(aeb, aeb_tmp, &ai->alien, u.list) {
 		list_del(&aeb->u.list);
@@ -1185,26 +1168,8 @@ static void destroy_ai(struct ubi_attach_info *ai)
 	}
 
 	/* Destroy the volume RB-tree */
-	rb = ai->volumes.rb_node;
-	while (rb) {
-		if (rb->rb_left)
-			rb = rb->rb_left;
-		else if (rb->rb_right)
-			rb = rb->rb_right;
-		else {
-			av = rb_entry(rb, struct ubi_ainf_volume, rb);
-
-			rb = rb_parent(rb);
-			if (rb) {
-				if (rb->rb_left == &av->rb)
-					rb->rb_left = NULL;
-				else
-					rb->rb_right = NULL;
-			}
-
-			destroy_av(ai, av);
-		}
-	}
+	rbtree_postorder_for_each_entry_safe(av, next, &ai->volumes, rb)
+		destroy_av(ai, av);
 
 	if (ai->aeb_slab_cache)
 		kmem_cache_destroy(ai->aeb_slab_cache);
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index c95bfb1..1af3899 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -1760,29 +1760,10 @@ int ubi_wl_flush(struct ubi_device *ubi, int vol_id, int lnum)
  */
 static void tree_destroy(struct rb_root *root)
 {
-	struct rb_node *rb;
-	struct ubi_wl_entry *e;
-
-	rb = root->rb_node;
-	while (rb) {
-		if (rb->rb_left)
-			rb = rb->rb_left;
-		else if (rb->rb_right)
-			rb = rb->rb_right;
-		else {
-			e = rb_entry(rb, struct ubi_wl_entry, u.rb);
-
-			rb = rb_parent(rb);
-			if (rb) {
-				if (rb->rb_left == &e->u.rb)
-					rb->rb_left = NULL;
-				else
-					rb->rb_right = NULL;
-			}
+	struct ubi_wl_entry *e, *next;
 
-			kmem_cache_free(ubi_wl_entry_slab, e);
-		}
-	}
+	rbtree_postorder_for_each_entry_safe(e, next, root, u.rb)
+		kmem_cache_free(ubi_wl_entry_slab, e);
 }
 
 /**
-- 
1.8.4.2