linux-kernel - [PATCH] drivers: regmap: bugfix in regcache-rbtree.c

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Message-Id: <1377090155-3443-1-git-send-email-david@protonic.nl>
Date:	Wed, 21 Aug 2013 15:02:35 +0200
From:	David Jander <david@...tonic.nl>
To:	Dimitris Papastamos <dp@...nsource.wolfsonmicro.com>
Cc:	Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org,
	David Jander <david@...tonic.nl>
Subject: [PATCH] drivers: regmap: bugfix in regcache-rbtree.c

The functionality of rbtree_ctx->cached_rbnode is broken. Remove it to
avoid hitting the wrong rbnode when locating a register.
rbnode register ranges can overlap, which is not a problem as long as
every lookup for a register returns the same rbnode. Therefor we need
to start searching from the top of the rb-tree _always_.

Signed-off-by: David Jander <david@...tonic.nl>
---
 drivers/base/regmap/regcache-rbtree.c | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c
index 5c1435c..2f9783f 100644
--- a/drivers/base/regmap/regcache-rbtree.c
+++ b/drivers/base/regmap/regcache-rbtree.c
@@ -35,7 +35,6 @@ struct regcache_rbtree_node {
 
 struct regcache_rbtree_ctx {
 	struct rb_root root;
-	struct regcache_rbtree_node *cached_rbnode;
 };
 
 static inline void regcache_rbtree_get_base_top_reg(
@@ -68,21 +67,12 @@ static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map,
 	struct regcache_rbtree_node *rbnode;
 	unsigned int base_reg, top_reg;
 
-	rbnode = rbtree_ctx->cached_rbnode;
-	if (rbnode) {
-		regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
-						 &top_reg);
-		if (reg >= base_reg && reg <= top_reg)
-			return rbnode;
-	}
-
 	node = rbtree_ctx->root.rb_node;
 	while (node) {
 		rbnode = container_of(node, struct regcache_rbtree_node, node);
 		regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
 						 &top_reg);
 		if (reg >= base_reg && reg <= top_reg) {
-			rbtree_ctx->cached_rbnode = rbnode;
 			return rbnode;
 		} else if (reg > top_reg) {
 			node = node->rb_right;
@@ -209,7 +199,6 @@ static int regcache_rbtree_init(struct regmap *map)
 
 	rbtree_ctx = map->cache;
 	rbtree_ctx->root = RB_ROOT;
-	rbtree_ctx->cached_rbnode = NULL;
 
 	for (i = 0; i < map->num_reg_defaults; i++) {
 		ret = regcache_rbtree_write(map,
@@ -392,7 +381,6 @@ static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
 								      value);
 				if (ret)
 					return ret;
-				rbtree_ctx->cached_rbnode = rbnode_tmp;
 				return 0;
 			}
 		}
@@ -406,7 +394,6 @@ static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
 		regcache_rbtree_set_register(map, rbnode,
 					     reg - rbnode->base_reg, value);
 		regcache_rbtree_insert(map, &rbtree_ctx->root, rbnode);
-		rbtree_ctx->cached_rbnode = rbnode;
 	}
 
 	return 0;
-- 
1.8.1.2

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