can: kvaser_usb: hydra: help gcc-13 to figure out cmd_len

Debian's gcc-13 [1] throws the following error in
kvaser_usb_hydra_cmd_size():

[1] gcc version 13.0.0 20221214 (experimental) [master r13-4693-g512098a3316] (Debian 13-20221214-1)

| drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c:502:65: error:
| array subscript ‘struct kvaser_cmd_ext[0]’ is partly outside array
| bounds of ‘unsigned char[32]’ [-Werror=array-bounds=]
|   502 |                 ret = le16_to_cpu(((struct kvaser_cmd_ext *)cmd)->len);

kvaser_usb_hydra_cmd_size() returns the size of given command. It
depends on the command number (cmd->header.cmd_no). For extended
commands (cmd->header.cmd_no == CMD_EXTENDED) the above shown code is
executed.

Help gcc to recognize that this code path is not taken in all cases,
by calling kvaser_usb_hydra_cmd_size() directly after assigning the
command number.

Fixes: aec5fb2 ("can: kvaser_usb: Add support for Kvaser USB hydra family")
Cc: Jimmy Assarsson <[email protected]>
Cc: Anssi Hannula <[email protected]>
Link: https://lore.kernel.org/all/[email protected]
Tested-by: Jimmy Assarsson <[email protected]>
Signed-off-by: Marc Kleine-Budde <[email protected]>

Author: marckleinebudde

drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c

@@ -545,13 +545,15 @@ static int kvaser_usb_hydra_send_simple_cmd(struct kvaser_usb *dev,
 					    u8 cmd_no, int channel)
 {
 	struct kvaser_cmd *cmd;
+	size_t cmd_len;
 	int err;
 
 	cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
 	if (!cmd)
 		return -ENOMEM;
 
 	cmd->header.cmd_no = cmd_no;
+	cmd_len = kvaser_usb_hydra_cmd_size(cmd);
 	if (channel < 0) {
 		kvaser_usb_hydra_set_cmd_dest_he
 				(cmd, KVASER_USB_HYDRA_HE_ADDRESS_ILLEGAL);
@@ -568,7 +570,7 @@ static int kvaser_usb_hydra_send_simple_cmd(struct kvaser_usb *dev,
 	kvaser_usb_hydra_set_cmd_transid
 				(cmd, kvaser_usb_hydra_get_next_transid(dev));
 
-	err = kvaser_usb_send_cmd(dev, cmd, kvaser_usb_hydra_cmd_size(cmd));
+	err = kvaser_usb_send_cmd(dev, cmd, cmd_len);
 	if (err)
 		goto end;
 
@@ -584,21 +586,22 @@ kvaser_usb_hydra_send_simple_cmd_async(struct kvaser_usb_net_priv *priv,
 {
 	struct kvaser_cmd *cmd;
 	struct kvaser_usb *dev = priv->dev;
+	size_t cmd_len;
 	int err;
 
 	cmd = kzalloc(sizeof(*cmd), GFP_ATOMIC);
 	if (!cmd)
 		return -ENOMEM;
 
 	cmd->header.cmd_no = cmd_no;
+	cmd_len = kvaser_usb_hydra_cmd_size(cmd);
 
 	kvaser_usb_hydra_set_cmd_dest_he
 		(cmd, dev->card_data.hydra.channel_to_he[priv->channel]);
 	kvaser_usb_hydra_set_cmd_transid
 				(cmd, kvaser_usb_hydra_get_next_transid(dev));
 
-	err = kvaser_usb_send_cmd_async(priv, cmd,
-					kvaser_usb_hydra_cmd_size(cmd));
+	err = kvaser_usb_send_cmd_async(priv, cmd, cmd_len);
 	if (err)
 		kfree(cmd);
 
@@ -742,6 +745,7 @@ static int kvaser_usb_hydra_get_single_capability(struct kvaser_usb *dev,
 {
 	struct kvaser_usb_dev_card_data *card_data = &dev->card_data;
 	struct kvaser_cmd *cmd;
+	size_t cmd_len;
 	u32 value = 0;
 	u32 mask = 0;
 	u16 cap_cmd_res;
@@ -753,13 +757,14 @@ static int kvaser_usb_hydra_get_single_capability(struct kvaser_usb *dev,
 		return -ENOMEM;
 
 	cmd->header.cmd_no = CMD_GET_CAPABILITIES_REQ;
+	cmd_len = kvaser_usb_hydra_cmd_size(cmd);
 	cmd->cap_req.cap_cmd = cpu_to_le16(cap_cmd_req);
 
 	kvaser_usb_hydra_set_cmd_dest_he(cmd, card_data->hydra.sysdbg_he);
 	kvaser_usb_hydra_set_cmd_transid
 				(cmd, kvaser_usb_hydra_get_next_transid(dev));
 
-	err = kvaser_usb_send_cmd(dev, cmd, kvaser_usb_hydra_cmd_size(cmd));
+	err = kvaser_usb_send_cmd(dev, cmd, cmd_len);
 	if (err)
 		goto end;
 
@@ -1578,6 +1583,7 @@ static int kvaser_usb_hydra_get_busparams(struct kvaser_usb_net_priv *priv,
 	struct kvaser_usb *dev = priv->dev;
 	struct kvaser_usb_net_hydra_priv *hydra = priv->sub_priv;
 	struct kvaser_cmd *cmd;
+	size_t cmd_len;
 	int err;
 
 	if (!hydra)
@@ -1588,6 +1594,7 @@ static int kvaser_usb_hydra_get_busparams(struct kvaser_usb_net_priv *priv,
 		return -ENOMEM;
 
 	cmd->header.cmd_no = CMD_GET_BUSPARAMS_REQ;
+	cmd_len = kvaser_usb_hydra_cmd_size(cmd);
 	kvaser_usb_hydra_set_cmd_dest_he
 		(cmd, dev->card_data.hydra.channel_to_he[priv->channel]);
 	kvaser_usb_hydra_set_cmd_transid
@@ -1597,7 +1604,7 @@ static int kvaser_usb_hydra_get_busparams(struct kvaser_usb_net_priv *priv,
 
 	reinit_completion(&priv->get_busparams_comp);
 
-	err = kvaser_usb_send_cmd(dev, cmd, kvaser_usb_hydra_cmd_size(cmd));
+	err = kvaser_usb_send_cmd(dev, cmd, cmd_len);
 	if (err)
 		return err;
 
@@ -1624,13 +1631,15 @@ static int kvaser_usb_hydra_set_bittiming(const struct net_device *netdev,
 	struct kvaser_cmd *cmd;
 	struct kvaser_usb_net_priv *priv = netdev_priv(netdev);
 	struct kvaser_usb *dev = priv->dev;
+	size_t cmd_len;
 	int err;
 
 	cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
 	if (!cmd)
 		return -ENOMEM;
 
 	cmd->header.cmd_no = CMD_SET_BUSPARAMS_REQ;
+	cmd_len = kvaser_usb_hydra_cmd_size(cmd);
 	memcpy(&cmd->set_busparams_req.busparams_nominal, busparams,
 	       sizeof(cmd->set_busparams_req.busparams_nominal));
 
@@ -1639,7 +1648,7 @@ static int kvaser_usb_hydra_set_bittiming(const struct net_device *netdev,
 	kvaser_usb_hydra_set_cmd_transid
 				(cmd, kvaser_usb_hydra_get_next_transid(dev));
 
-	err = kvaser_usb_send_cmd(dev, cmd, kvaser_usb_hydra_cmd_size(cmd));
+	err = kvaser_usb_send_cmd(dev, cmd, cmd_len);
 
 	kfree(cmd);
 
@@ -1652,13 +1661,15 @@ static int kvaser_usb_hydra_set_data_bittiming(const struct net_device *netdev,
 	struct kvaser_cmd *cmd;
 	struct kvaser_usb_net_priv *priv = netdev_priv(netdev);
 	struct kvaser_usb *dev = priv->dev;
+	size_t cmd_len;
 	int err;
 
 	cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
 	if (!cmd)
 		return -ENOMEM;
 
 	cmd->header.cmd_no = CMD_SET_BUSPARAMS_FD_REQ;
+	cmd_len = kvaser_usb_hydra_cmd_size(cmd);
 	memcpy(&cmd->set_busparams_req.busparams_data, busparams,
 	       sizeof(cmd->set_busparams_req.busparams_data));
 
@@ -1676,7 +1687,7 @@ static int kvaser_usb_hydra_set_data_bittiming(const struct net_device *netdev,
 	kvaser_usb_hydra_set_cmd_transid
 				(cmd, kvaser_usb_hydra_get_next_transid(dev));
 
-	err = kvaser_usb_send_cmd(dev, cmd, kvaser_usb_hydra_cmd_size(cmd));
+	err = kvaser_usb_send_cmd(dev, cmd, cmd_len);
 
 	kfree(cmd);
 
@@ -1804,6 +1815,7 @@ static int kvaser_usb_hydra_get_software_info(struct kvaser_usb *dev)
 static int kvaser_usb_hydra_get_software_details(struct kvaser_usb *dev)
 {
 	struct kvaser_cmd *cmd;
+	size_t cmd_len;
 	int err;
 	u32 flags;
 	struct kvaser_usb_dev_card_data *card_data = &dev->card_data;
@@ -1813,14 +1825,15 @@ static int kvaser_usb_hydra_get_software_details(struct kvaser_usb *dev)
 		return -ENOMEM;
 
 	cmd->header.cmd_no = CMD_GET_SOFTWARE_DETAILS_REQ;
+	cmd_len = kvaser_usb_hydra_cmd_size(cmd);
 	cmd->sw_detail_req.use_ext_cmd = 1;
 	kvaser_usb_hydra_set_cmd_dest_he
 				(cmd, KVASER_USB_HYDRA_HE_ADDRESS_ILLEGAL);
 
 	kvaser_usb_hydra_set_cmd_transid
 				(cmd, kvaser_usb_hydra_get_next_transid(dev));
 
-	err = kvaser_usb_send_cmd(dev, cmd, kvaser_usb_hydra_cmd_size(cmd));
+	err = kvaser_usb_send_cmd(dev, cmd, cmd_len);
 	if (err)
 		goto end;
 
@@ -1938,6 +1951,7 @@ static int kvaser_usb_hydra_set_opt_mode(const struct kvaser_usb_net_priv *priv)
 {
 	struct kvaser_usb *dev = priv->dev;
 	struct kvaser_cmd *cmd;
+	size_t cmd_len;
 	int err;
 
 	if ((priv->can.ctrlmode &
@@ -1953,6 +1967,7 @@ static int kvaser_usb_hydra_set_opt_mode(const struct kvaser_usb_net_priv *priv)
 		return -ENOMEM;
 
 	cmd->header.cmd_no = CMD_SET_DRIVERMODE_REQ;
+	cmd_len = kvaser_usb_hydra_cmd_size(cmd);
 	kvaser_usb_hydra_set_cmd_dest_he
 		(cmd, dev->card_data.hydra.channel_to_he[priv->channel]);
 	kvaser_usb_hydra_set_cmd_transid
@@ -1962,7 +1977,7 @@ static int kvaser_usb_hydra_set_opt_mode(const struct kvaser_usb_net_priv *priv)
 	else
 		cmd->set_ctrlmode.mode = KVASER_USB_HYDRA_CTRLMODE_NORMAL;
 
-	err = kvaser_usb_send_cmd(dev, cmd, kvaser_usb_hydra_cmd_size(cmd));
+	err = kvaser_usb_send_cmd(dev, cmd, cmd_len);
 	kfree(cmd);
 
 	return err;