[PATCH 8/9] regmap: use cleanup API in __regmap_init()

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@xxxxxxx>

Convert the error unwinding in __regmap_init() to the scope-based
cleanup API and drop all of the err_* labels. A dedicated
regmap_init_release() helper unwinds a partially initialised map in the
same order as the old labels.

The err label only returned ERR_PTR(ret) after the per-device bus
allocation was removed, so the two early failure paths now return
directly as well.

regcache_exit() requires an initialised cache, so map->cache_type is now
set right before regcache_init() instead of during the initial map setup
and reset to REGCACHE_NONE if regcache_init() fails. This makes
regcache_exit() safe to call from the cleanup path at any point. Nothing
between the old and new assignment reads cache_type.

No functional change.

Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
---
 drivers/base/regmap/regmap.c | 66 +++++++++++++++++++++-----------------------
 1 file changed, 32 insertions(+), 34 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index c5acfe687d9c..fdd538afaae4 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1037,6 +1037,22 @@ static int regmap_init_format(struct regmap *map,
 	return 0;
 }
 
+static void regmap_init_release(struct regmap *map)
+{
+	if (!map)
+		return;
+
+	regcache_exit(map);
+	regmap_range_exit(map);
+	kfree(map->work_buf);
+	if (map->hwlock)
+		hwspin_lock_free(map->hwlock);
+	kfree_const(map->name);
+	kfree(map);
+}
+
+DEFINE_FREE(regmap_init_release, struct regmap *, regmap_init_release(_T));
+
 struct regmap *__regmap_init(struct device *dev,
 			     const struct regmap_bus *bus,
 			     void *bus_context,
@@ -1044,29 +1060,25 @@ struct regmap *__regmap_init(struct device *dev,
 			     struct lock_class_key *lock_key,
 			     const char *lock_name)
 {
-	struct regmap *map;
 	bool fast_io;
 	int ret = -EINVAL;
 
 	if (!config)
-		goto err;
+		return ERR_PTR(-EINVAL);
 
-	map = kzalloc_obj(*map);
-	if (map == NULL) {
-		ret = -ENOMEM;
-		goto err;
-	}
+	struct regmap *map __free(regmap_init_release) = kzalloc_obj(*map);
+	if (map == NULL)
+		return ERR_PTR(-ENOMEM);
 
 	ret = regmap_set_name(map, config);
 	if (ret)
-		goto err_map;
-
+		return ERR_PTR(ret);
 
 	fast_io = (bus && bus->fast_io) || config->fast_io;
 
 	ret = regmap_set_lock(map, config, fast_io, lock_key, lock_name);
 	if (ret)
-		goto err_name;
+		return ERR_PTR(ret);
 
 	/*
 	 * When we write in fast-paths with regmap_bulk_write() don't allocate
@@ -1118,7 +1130,6 @@ struct regmap *__regmap_init(struct device *dev,
 	map->writeable_noinc_reg = config->writeable_noinc_reg;
 	map->readable_noinc_reg = config->readable_noinc_reg;
 	map->reg_default_cb = config->reg_default_cb;
-	map->cache_type = config->cache_type;
 
 	spin_lock_init(&map->async_lock);
 	INIT_LIST_HEAD(&map->async_list);
@@ -1147,7 +1158,7 @@ struct regmap *__regmap_init(struct device *dev,
 					 REGMAP_ENDIAN_NATIVE,
 					 REGMAP_ENDIAN_NATIVE);
 		if (ret)
-			goto err_hwlock;
+			return ERR_PTR(ret);
 	} else if (!bus) {
 		map->reg_read  = config->reg_read;
 		map->reg_write = config->reg_write;
@@ -1171,45 +1182,32 @@ struct regmap *__regmap_init(struct device *dev,
 					 regmap_get_reg_endian(bus, config),
 					 regmap_get_val_endian(dev, bus, config));
 		if (ret)
-			goto err_hwlock;
+			return ERR_PTR(ret);
 	}
 
-
 	ret = regmap_init_ranges(map, config);
 	if (ret)
-		goto err_range;
+		return ERR_PTR(ret);
 
 	if (bus && bus->init_limits)
 		bus->init_limits(map, config);
 
+	map->cache_type = config->cache_type;
 	ret = regcache_init(map, config);
-	if (ret != 0)
-		goto err_range;
+	if (ret) {
+		map->cache_type = REGCACHE_NONE;
+		return ERR_PTR(ret);
+	}
 
 	if (dev) {
 		ret = regmap_attach_dev(dev, map, config);
 		if (ret != 0)
-			goto err_regcache;
+			return ERR_PTR(ret);
 	} else {
 		regmap_debugfs_init(map);
 	}
 
-	return map;
-
-err_regcache:
-	regcache_exit(map);
-err_range:
-	regmap_range_exit(map);
-	kfree(map->work_buf);
-err_hwlock:
-	if (map->hwlock)
-		hwspin_lock_free(map->hwlock);
-err_name:
-	kfree_const(map->name);
-err_map:
-	kfree(map);
-err:
-	return ERR_PTR(ret);
+	return_ptr(map);
 }
 EXPORT_SYMBOL_GPL(__regmap_init);
 

-- 
2.51.0