[PATCH] soundwire: stream: fix an invalid free

[trix@redhat.com]

From: Tom Rix <trix@redhat.com>

clang static analyzer reports this problem

stream.c:872:2: warning: Argument to kfree() is a constant
  address (18446744073709551092), which is not memory
  allocated by malloc()
        kfree(stream);
        ^~~~~~~~~~~~~

In sdw_shutdown_stream() the stream to free is set by
a call to snd_soc_dai_get_sdw_stream().  The problem block
is the check if the call was successful.

	if (!sdw_stream) {
		dev_err(rtd->dev, "no stream found...
		return;
	}

When snd_soc_dai_get_sdw_stream() fails, it does not
always return null, sometimes it returns -ENOTSUPP.

So also check for error codes.

Fixes: 4550569bd779 ("soundwire: stream: add helper to startup/shutdown streams")
Signed-off-by: Tom Rix <trix@redhat.com>
---
 drivers/soundwire/stream.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index 6e36deb505b1..950231d593c2 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -1913,7 +1913,7 @@ void sdw_shutdown_stream(void *sdw_substream)
 
 	sdw_stream = snd_soc_dai_get_sdw_stream(dai, substream->stream);
 
-	if (!sdw_stream) {
+	if (IS_ERR_OR_NULL(sdw_stream)) {
 		dev_err(rtd->dev, "no stream found for DAI %s", dai->name);
 		return;
 	}
-- 
2.18.1