[PATCH v1 3/4] regmap: Defer assignments to the later in some cases

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

In some cases the assignments at the top of the certain functions
belong to smaller subset of the functionality and may be located
too far from their actual users. Defer them to the later.

This makes code robust against potential changes that may lead to
the corruption of the respected values.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/base/regmap/regmap.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 0617a957559b..1855b5fc76da 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -681,12 +681,14 @@ struct regmap *__regmap_init(struct device *dev,
 			     const char *lock_name)
 {
 	struct regmap *map;
-	int ret = -EINVAL;
 	enum regmap_endian reg_endian, val_endian;
 	int i, j;
+	int ret;
 
-	if (!config)
+	if (!config) {
+		ret = -EINVAL;
 		goto err;
+	}
 
 	map = kzalloc_obj(*map);
 	if (map == NULL) {
@@ -1604,8 +1606,7 @@ static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
 {
 	struct regmap_range_node *range;
 	unsigned long flags;
-	void *work_val = map->work_buf + map->format.reg_bytes +
-		map->format.pad_bytes;
+	void *work_val;
 	void *buf;
 	int ret = -ENOTSUPP;
 	size_t len;
@@ -1688,6 +1689,7 @@ static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
 	 * buffer to write.  Since register syncs often generate raw
 	 * writes of single registers optimise that case.
 	 */
+	work_val = map->work_buf + map->format.reg_bytes + map->format.pad_bytes;
 	if (val != work_val && val_len == map->format.val_bytes) {
 		memcpy(work_val, val, map->format.val_bytes);
 		val = work_val;
@@ -2291,8 +2293,8 @@ EXPORT_SYMBOL_GPL(regmap_fields_update_bits_base);
 int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
 		     size_t val_count)
 {
-	int ret = 0, i;
 	size_t val_bytes = map->format.val_bytes;
+	int ret, i;
 
 	if (!IS_ALIGNED(reg, map->reg_stride))
 		return -EINVAL;
@@ -2302,6 +2304,8 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
 	 * single write operations.
 	 */
 	if (!map->write || !map->format.parse_inplace) {
+		ret = 0; /* Later error paths rely on this */
+
 		guard(regmap)(map);
 
 		for (i = 0; i < val_count; i++) {
@@ -2739,12 +2743,12 @@ static int _regmap_bus_read(void *context, unsigned int reg,
 {
 	int ret;
 	struct regmap *map = context;
-	void *work_val = map->work_buf + map->format.reg_bytes +
-		map->format.pad_bytes;
+	void *work_val;
 
 	if (!map->format.parse_val)
 		return -EINVAL;
 
+	work_val = map->work_buf + map->format.reg_bytes + map->format.pad_bytes;
 	ret = _regmap_raw_read(map, reg, work_val, map->format.val_bytes, false);
 	if (ret == 0)
 		*val = map->format.parse_val(work_val);
-- 
2.50.1