[PATCH] regmap: fix a NULL pointer dereference in __regmap_init

[Sergey SENOZHATSKY]

__regmap_init() may receive a NULL `struct regmap_bus *bus' pointer,
for example, from snd_hdac_regmap_init(), and it make sure that it
does not NULL deference `bus`, except around ->max_raw_read and
->max_raw_write initialisation. Add missing check.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
 drivers/base/regmap/regmap.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index d2efa4b..2ffdb62 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -579,8 +579,10 @@ struct regmap *regmap_init(struct device *dev,
 	map->use_single_read = config->use_single_rw || !bus || !bus->read;
 	map->use_single_write = config->use_single_rw || !bus || !bus->write;
 	map->can_multi_write = config->can_multi_write && bus && bus->write;
-	map->max_raw_read = bus->max_raw_read;
-	map->max_raw_write = bus->max_raw_write;
+	if (bus) {
+		map->max_raw_read = bus->max_raw_read;
+		map->max_raw_write = bus->max_raw_write;
+	}
 	map->dev = dev;
 	map->bus = bus;
 	map->bus_context = bus_context;
-- 
2.5.0

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