regmap: fix a NULL pointer dereference in __regmap_init

__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@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index d2efa4b33294353a8691fef74258a5bde0d3bc18..2ffdb62f75f7306ce1fca9468b7f51566cc6ed67 100644 (file)
--- 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;