soundwire: stream: fix bad unlock balance

the msg lock is taken for multi-link cases only but released
unconditionally, leading to an unlock balance warning for single-link usages
This patch fixes this.

 =====================================
 WARNING: bad unlock balance detected!
 5.1.0-16506-gc1c383a6f0a2-dirty #1523 Tainted: G        W
 -------------------------------------
 aplay/2954 is trying to release lock (&bus->msg_lock) at:
 do_bank_switch+0x21c/0x480
 but there are no more locks to release!

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Acked-by: Sanyog Kale <sanyog.r.kale@intel.com>
[vkoul: edited the change log as suggested by Pierre]
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index 544925ff0b40..1d5294b8783b 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -814,7 +814,8 @@ static int do_bank_switch(struct sdw_stream_runtime *stream)
                         goto error;
                 }
 
-                mutex_unlock(&bus->msg_lock);
+                if (bus->multi_link)
+                        mutex_unlock(&bus->msg_lock);
         }
 
         return ret;