[PATCH RFC v2 2/4] regcache: use the regmap scoped lock guard

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@xxxxxxx>

Convert the open-coded map->lock()/map->unlock() users in regcache.c
to the regmap scoped guard introduced for regmap.c. Use
scoped_guard(regmap, ...) in regcache_init() and regcache_exit(),
where the locked region is a subsection of the function, and
guard(regmap)() for the function-scope critical sections.

regcache_sync() and regcache_sync_region() are left as-is: they
already use a single goto out unlock path, so converting them would
require either mixing a goto with a scoped_guard scope or restructuring
their control flow, neither of which is an improvement.

regcache_init() keeps its goto err_* cleanup ladder alongside the
scoped_guard(). This does not conflict with the cleanup.h guidance
against mixing goto with cleanup helpers: that rule concerns a single
resource whose lifetime is managed by a goto. Here the goto ladder
only unwinds the allocation / hw-init path (kfree(map->reg_defaults),
regcache_hw_exit(), ->exit()), while the scoped_guard() covers a
different resource - the transient map lock around each callback - that
is acquired and released within its one-line scope and is never held
across a goto. The two mechanisms manage independent resources and no
goto ever crosses a live guard.

No functional change.

Assisted-by: Claude:claude-opus-4.8
Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
---
 drivers/base/regmap/regcache.c | 43 ++++++++++++++----------------------------
 1 file changed, 14 insertions(+), 29 deletions(-)

diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 0d58d900a2ca..d030fcbe11d9 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -225,9 +225,8 @@ int regcache_init(struct regmap *map, const struct regmap_config *config)
 	if (map->cache_ops->init) {
 		dev_dbg(map->dev, "Initializing %s cache\n",
 			map->cache_ops->name);
-		map->lock(map->lock_arg);
-		ret = map->cache_ops->init(map);
-		map->unlock(map->lock_arg);
+		scoped_guard(regmap, map)
+			ret = map->cache_ops->init(map);
 		if (ret)
 			goto err_free_reg_defaults;
 	}
@@ -246,9 +245,8 @@ int regcache_init(struct regmap *map, const struct regmap_config *config)
 	if (map->cache_ops->populate &&
 	    (map->num_reg_defaults || map->reg_default_cb)) {
 		dev_dbg(map->dev, "Populating %s cache\n", map->cache_ops->name);
-		map->lock(map->lock_arg);
-		ret = map->cache_ops->populate(map);
-		map->unlock(map->lock_arg);
+		scoped_guard(regmap, map)
+			ret = map->cache_ops->populate(map);
 		if (ret)
 			goto err_free;
 	}
@@ -259,9 +257,8 @@ int regcache_init(struct regmap *map, const struct regmap_config *config)
 err_exit:
 	if (map->cache_ops->exit) {
 		dev_dbg(map->dev, "Destroying %s cache\n", map->cache_ops->name);
-		map->lock(map->lock_arg);
-		map->cache_ops->exit(map);
-		map->unlock(map->lock_arg);
+		scoped_guard(regmap, map)
+			map->cache_ops->exit(map);
 	}
 err_free_reg_defaults:
 	kfree(map->reg_defaults);
@@ -281,9 +278,8 @@ void regcache_exit(struct regmap *map)
 	if (map->cache_ops->exit) {
 		dev_dbg(map->dev, "Destroying %s cache\n",
 			map->cache_ops->name);
-		map->lock(map->lock_arg);
-		map->cache_ops->exit(map);
-		map->unlock(map->lock_arg);
+		scoped_guard(regmap, map)
+			map->cache_ops->exit(map);
 	}
 
 	kfree(map->reg_defaults);
@@ -584,20 +580,14 @@ EXPORT_SYMBOL_GPL(regcache_sync_region);
 int regcache_drop_region(struct regmap *map, unsigned int min,
 			 unsigned int max)
 {
-	int ret = 0;
-
 	if (!map->cache_ops || !map->cache_ops->drop)
 		return -EINVAL;
 
-	map->lock(map->lock_arg);
+	guard(regmap)(map);
 
 	trace_regcache_drop_region(map, min, max);
 
-	ret = map->cache_ops->drop(map, min, max);
-
-	map->unlock(map->lock_arg);
-
-	return ret;
+	return map->cache_ops->drop(map, min, max);
 }
 EXPORT_SYMBOL_GPL(regcache_drop_region);
 
@@ -615,12 +605,11 @@ EXPORT_SYMBOL_GPL(regcache_drop_region);
  */
 void regcache_cache_only(struct regmap *map, bool enable)
 {
-	map->lock(map->lock_arg);
+	guard(regmap)(map);
 	WARN_ON(map->cache_type != REGCACHE_NONE &&
 		map->cache_bypass && enable);
 	map->cache_only = enable;
 	trace_regmap_cache_only(map, enable);
-	map->unlock(map->lock_arg);
 }
 EXPORT_SYMBOL_GPL(regcache_cache_only);
 
@@ -639,10 +628,9 @@ EXPORT_SYMBOL_GPL(regcache_cache_only);
  */
 void regcache_mark_dirty(struct regmap *map)
 {
-	map->lock(map->lock_arg);
+	guard(regmap)(map);
 	map->cache_dirty = true;
 	map->no_sync_defaults = true;
-	map->unlock(map->lock_arg);
 }
 EXPORT_SYMBOL_GPL(regcache_mark_dirty);
 
@@ -659,11 +647,10 @@ EXPORT_SYMBOL_GPL(regcache_mark_dirty);
  */
 void regcache_cache_bypass(struct regmap *map, bool enable)
 {
-	map->lock(map->lock_arg);
+	guard(regmap)(map);
 	WARN_ON(map->cache_only && enable);
 	map->cache_bypass = enable;
 	trace_regmap_cache_bypass(map, enable);
-	map->unlock(map->lock_arg);
 }
 EXPORT_SYMBOL_GPL(regcache_cache_bypass);
 
@@ -680,12 +667,10 @@ bool regcache_reg_cached(struct regmap *map, unsigned int reg)
 	unsigned int val;
 	int ret;
 
-	map->lock(map->lock_arg);
+	guard(regmap)(map);
 
 	ret = regcache_read(map, reg, &val);
 
-	map->unlock(map->lock_arg);
-
 	return ret == 0;
 }
 EXPORT_SYMBOL_GPL(regcache_reg_cached);

-- 
2.51.0