ASoC: SOF: ipc4-topology: Correct the allocation size for bytes controls

The size of the data behind of scontrol->ipc_control_data for bytes
controls is:
[1] sizeof(struct sof_ipc4_control_data) + // kernel only struct
[2] sizeof(struct sof_abi_hdr)) + payload

The max_size specifies the size of [2] and it is coming from topology.

Change the function to take this into account and allocate adequate amount
of memory behind scontrol->ipc_control_data.

With the change we will allocate [1] amount more memory to be able to hold
the full size of data.

Fixes: 1bfde58 ("ASoC: SOF: ipc4-topology: add byte kcontrol support")
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

Author: ujfalusi

sound/soc/sof/ipc4-topology.c

@@ -2875,22 +2875,41 @@ static int sof_ipc4_control_load_bytes(struct snd_sof_dev *sdev, struct snd_sof_
 	struct sof_ipc4_msg *msg;
 	int ret;
 
-	if (scontrol->max_size < (sizeof(*control_data) + sizeof(struct sof_abi_hdr))) {
-		dev_err(sdev->dev, "insufficient size for a bytes control %s: %zu.\n",
+	/*
+	 * The max_size is coming from topology and indicates the maximum size
+	 * of sof_abi_hdr plus the payload, which excludes the local only
+	 * 'struct sof_ipc4_control_data'
+	 */
+	if (scontrol->max_size < sizeof(struct sof_abi_hdr)) {
+		dev_err(sdev->dev,
+			"insufficient maximum size for a bytes control %s: %zu.\n",
 			scontrol->name, scontrol->max_size);
 		return -EINVAL;
 	}
 
-	if (scontrol->priv_size > scontrol->max_size - sizeof(*control_data)) {
-		dev_err(sdev->dev, "scontrol %s bytes data size %zu exceeds max %zu.\n",
-			scontrol->name, scontrol->priv_size,
-			scontrol->max_size - sizeof(*control_data));
+	if (scontrol->priv_size > scontrol->max_size) {
+		dev_err(sdev->dev,
+			"bytes control %s initial data size %zu exceeds max %zu.\n",
+			scontrol->name, scontrol->priv_size, scontrol->max_size);
+		return -EINVAL;
+	}
+
+	if (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);
 		return -EINVAL;
 	}
 
-	scontrol->size = sizeof(struct sof_ipc4_control_data) + scontrol->priv_size;
+	/*
+	 * The used size behind the cdata pointer, which can be smaller than
+	 * the maximum size
+	 */
+	scontrol->size = sizeof(*control_data) + scontrol->priv_size;
 
-	scontrol->ipc_control_data = kzalloc(scontrol->max_size, GFP_KERNEL);
+	/* Allocate the cdata: local struct size + maximum payload size */
+	scontrol->ipc_control_data = kzalloc(sizeof(*control_data) + scontrol->max_size,
+					     GFP_KERNEL);
 	if (!scontrol->ipc_control_data)
 		return -ENOMEM;