[PATCH] regmap: fix deadlock on _regmap_raw_write() error path

[Nikita Yushchenko]

Commit 815806e39bf6 ("regmap: drop cache if the bus transfer error")
added a call to regcache_drop_region() to error path in
_regmap_raw_write(). However that path runs with regmap lock taken,
and regcache_drop_region() tries to re-take it, causing a deadlock.
Fix that by calling map->cache_ops->drop() directly.

Signed-off-by: Nikita Yushchenko <nikita.yoush@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
 drivers/base/regmap/regmap.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 25d26bb18970..e964d068874d 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1475,7 +1475,11 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
 
 		kfree(buf);
 	} else if (ret != 0 && !map->cache_bypass && map->format.parse_val) {
-		regcache_drop_region(map, reg, reg + 1);
+		/* regcache_drop_region() takes lock that we already have,
+		 * thus call map->cache_ops->drop() directly
+		 */
+		if (map->cache_ops && map->cache_ops->drop)
+			map->cache_ops->drop(map, reg, reg + 1);
 	}
 
 	trace_regmap_hw_write_done(map, reg, val_len / map->format.val_bytes);
-- 
2.8.1