[PATCH] soundwire: stream: sdw_stream_remove_slave(): Check stream is valid

[Richard Fitzgerald <rf@opensource.cirrus.com>]

In sdw_stream_remove_slave() check that stream is a valid pointer
before passing it to functions that dereference it. Return 0 if the
pointer is invalid.

This is a convenience for callers. They can safely call this function
during cleanup code without needing a pointer validity check duplicated
at every call point.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
---
 drivers/soundwire/stream.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index 4ed8fb7663ad..c1ef177a0021 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -2229,11 +2229,15 @@ EXPORT_SYMBOL(sdw_stream_add_slave);
  * @slave: SDW Slave instance
  * @stream: SoundWire stream
  *
- * This removes and frees port_rt and slave_rt from a stream
+ * This removes and frees port_rt and slave_rt from a stream.
+ * If stream is NULL or an ERR_PTR, do nothing and return 0.
  */
 int sdw_stream_remove_slave(struct sdw_slave *slave,
 			    struct sdw_stream_runtime *stream)
 {
+	if (IS_ERR_OR_NULL(stream))
+		return 0;
+
 	mutex_lock(&slave->bus->bus_lock);
 
 	sdw_slave_port_free(slave, stream);
-- 
2.47.3