[SRU][Focal][PATCH 4/4] ASoC: SOF: trace: fix unconditional free in trace release

[Hui Wang]

From: Kai Vehmanen <kai.vehmanen at linux.intel.com>

BugLink: https://bugs.launchpad.net/bugs/1861837

Check if DMA pages were successfully allocated in initialization
before calling free. For many types of memory (like sgbufs)
the extra free is harmless, but not all backends track allocation
state, so add an explicit check.

Signed-off-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
Link: https://lore.kernel.org/r/20200124213625.30186-5-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie at kernel.org>
(cherry picked from commit e6110114d18d330c05fd6de9f31283fd086a5a3a)
Signed-off-by: Hui Wang <hui.wang at canonical.com>
---
 sound/soc/sof/trace.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sound/soc/sof/trace.c b/sound/soc/sof/trace.c
index 4c3cff031fd6..fd6f5913782b 100644
--- a/sound/soc/sof/trace.c
+++ b/sound/soc/sof/trace.c
@@ -328,7 +328,10 @@ void snd_sof_free_trace(struct snd_sof_dev *sdev)
 {
 	snd_sof_release_trace(sdev);
 
-	snd_dma_free_pages(&sdev->dmatb);
-	snd_dma_free_pages(&sdev->dmatp);
+	if (sdev->dma_trace_pages) {
+		snd_dma_free_pages(&sdev->dmatb);
+		snd_dma_free_pages(&sdev->dmatp);
+		sdev->dma_trace_pages = 0;
+	}
 }
 EXPORT_SYMBOL(snd_sof_free_trace);
-- 
2.17.1