ASoC: SOF: pcm: fix resource leak in hw_free

Fix a bug in sof_pcm_hw_free() where some cleanup actions were
skipped if STREAM_PCM_FREE IPC was already successfully sent to
DSP when the stream was stopped or suspended. This is incorrect
as hw_free should clean up also other resources, including pcm
lib page allocations, period elapsed work queue and call to
platform hw_free.

Fixes: c29d96c3b9b4 ("ASoC: SOF: reset DMA state in prepare")
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190927200538.660-6-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/pcm.c

@@ -244,7 +244,7 @@ static int sof_pcm_hw_free(struct snd_pcm_substream *substream)
 		snd_soc_rtdcom_lookup(rtd, DRV_NAME);
 	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(component);
 	struct snd_sof_pcm *spcm;
-	int ret;
+	int ret, err = 0;
 
 	/* nothing to do for BE */
 	if (rtd->dai_link->no_pcm)
@@ -254,26 +254,26 @@ static int sof_pcm_hw_free(struct snd_pcm_substream *substream)
 	if (!spcm)
 		return -EINVAL;
 
-	if (!spcm->prepared[substream->stream])
-		return 0;
-
 	dev_dbg(sdev->dev, "pcm: free stream %d dir %d\n", spcm->pcm.pcm_id,
 		substream->stream);
 
+	if (spcm->prepared[substream->stream]) {
 		ret = sof_pcm_dsp_pcm_free(substream, sdev, spcm);
+		if (ret < 0)
+			err = ret;
+	}
 
 	snd_pcm_lib_free_pages(substream);
 
 	cancel_work_sync(&spcm->stream[substream->stream].period_elapsed_work);
 
-	if (ret < 0)
-		return ret;
-
 	ret = snd_sof_pcm_platform_hw_free(sdev, substream);
-	if (ret < 0)
+	if (ret < 0) {
 		dev_err(sdev->dev, "error: platform hw free failed\n");
+		err = ret;
+	}
 
-	return ret;
+	return err;
 }
 
 static int sof_pcm_prepare(struct snd_pcm_substream *substream)