[PATCH 2/4] ASoC: SOF: ipc: check ipc return value before data copy

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

From: Jaska Uimonen <jaska.uimonen@linux.intel.com>

In tx_wait_done the ipc payload is copied before the DSP transaction
error code is checked. This might lead to corrupted data in kernel side
even though the error would be handled later. It is also pointless to
copy the data in case of error. So change the order of error check and
copy.

Signed-off-by: Jaska Uimonen <jaska.uimonen@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 sound/soc/sof/ipc.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/sound/soc/sof/ipc.c b/sound/soc/sof/ipc.c
index 22d296f95761..cc5762706c9c 100644
--- a/sound/soc/sof/ipc.c
+++ b/sound/soc/sof/ipc.c
@@ -214,15 +214,17 @@ static int tx_wait_done(struct snd_sof_ipc *ipc, struct snd_sof_ipc_msg *msg,
 		snd_sof_handle_fw_exception(ipc->sdev);
 		ret = -ETIMEDOUT;
 	} else {
-		/* copy the data returned from DSP */
 		ret = msg->reply_error;
-		if (msg->reply_size)
-			memcpy(reply_data, msg->reply_data, msg->reply_size);
-		if (ret < 0)
+		if (ret < 0) {
 			dev_err(sdev->dev, "error: ipc error for 0x%x size %zu\n",
 				hdr->cmd, msg->reply_size);
-		else
+		} else {
 			ipc_log_header(sdev->dev, "ipc tx succeeded", hdr->cmd);
+			if (msg->reply_size)
+				/* copy the data returned from DSP */
+				memcpy(reply_data, msg->reply_data,
+				       msg->reply_size);
+		}
 	}
 
 	return ret;
-- 
2.20.1