[PATCH for 7.0] ASoC: SOF: ipc4-topology: Allow bytes controls without initial payload

[Peter Ujfalusi <peter.ujfalusi@linux.intel.com>]

It is unexpected, but allowed to have no initial payload for a bytes
control and the code is prepared to handle this case, but the size check
missed this corner case.

Update the check for minimal size to allow the initial size to be 0.

Cc: stable@vger.kernel.org
Fixes: a653820700b8 ("ASoC: SOF: ipc4-topology: Correct the allocation size for bytes controls")
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Liam Girdwood <liam.r.girdwood@intel.com>
Reviewed-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
---
Hi Mark,

The patch that this is fixing is in 7.0-rc which is marked to be
backported [1], so I guess this patch will follow it in this way or need
to point to the older patch to be carried back?

[1] a382082ff74b ("ASoC: SOF: ipc4-topology: Add support for TPLG_CTL_BYTES")

Regards,
Peter

 sound/soc/sof/ipc4-topology.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/sof/ipc4-topology.c b/sound/soc/sof/ipc4-topology.c
index 82f1e44a145e..76812d8fb567 100644
--- a/sound/soc/sof/ipc4-topology.c
+++ b/sound/soc/sof/ipc4-topology.c
@@ -2951,7 +2951,7 @@ static int sof_ipc4_control_load_bytes(struct snd_sof_dev *sdev, struct snd_sof_
 		return -EINVAL;
 	}
 
-	if (scontrol->priv_size < sizeof(struct sof_abi_hdr)) {
+	if (scontrol->priv_size && scontrol->priv_size < sizeof(struct sof_abi_hdr)) {
 		dev_err(sdev->dev,
 			"bytes control %s initial data size %zu is insufficient.\n",
 			scontrol->name, scontrol->priv_size);
-- 
2.53.0