Commit 2a27f6a8 authored by Celeste Liu's avatar Celeste Liu Committed by Marc Kleine-Budde
Browse files

can: gs_usb: increase max interface to U8_MAX 

This issue was found by Runcheng Lu when develop HSCanT USB to CAN FD
converter[1]. The original developers may have only 3 interfaces
device to test so they write 3 here and wait for future change.

During the HSCanT development, we actually used 4 interfaces, so the
limitation of 3 is not enough now. But just increase one is not
future-proofed. Since the channel index type in gs_host_frame is u8,
just make canch[] become a flexible array with a u8 index, so it
naturally constraint by U8_MAX and avoid statically allocate 256
pointer for every gs_usb device.

[1]: https://github.com/cherry-embedded/HSCanT-hardware



Fixes: d08e973a ("can: gs_usb: Added support for the GS_USB CAN devices")
Reported-by: default avatarRuncheng Lu <runcheng.lu@hpmicro.com>
Cc: stable@vger.kernel.org
Reviewed-by: default avatarVincent Mailhol <mailhol@kernel.org>
Signed-off-by: default avatarCeleste Liu <uwu@coelacanthus.name>
Link: https://patch.msgid.link/20250930-gs-usb-max-if-v5-1-863330bf6666@coelacanthus.name


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 2c95a756

drivers/net/can/usb/gs_usb.c

+10 −12
Original line number Diff line number Diff line
@@ -289,11 +289,6 @@ struct gs_host_frame { 
#define GS_MAX_RX_URBS 30

#define GS_NAPI_WEIGHT 32



/* Maximum number of interfaces the driver supports per device.

 * Current hardware only supports 3 interfaces. The future may vary.

 */

#define GS_MAX_INTF 3



struct gs_tx_context {

	struct gs_can *dev;

	unsigned int echo_id;
@@ -324,7 +319,6 @@ struct gs_can { 


/* usb interface struct */

struct gs_usb {

	struct gs_can *canch[GS_MAX_INTF];

	struct usb_anchor rx_submitted;

	struct usb_device *udev;
@@ -336,9 +330,11 @@ struct gs_usb { 


	unsigned int hf_size_rx;

	u8 active_channels;

	u8 channel_cnt;



	unsigned int pipe_in;

	unsigned int pipe_out;

	struct gs_can *canch[] __counted_by(channel_cnt);

};



/* 'allocate' a tx context.
@@ -599,7 +595,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb) 
	}



	/* device reports out of range channel id */

	if (hf->channel >= GS_MAX_INTF)

	if (hf->channel >= parent->channel_cnt)

		goto device_detach;



	dev = parent->canch[hf->channel];
@@ -699,7 +695,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb) 
	/* USB failure take down all interfaces */

	if (rc == -ENODEV) {

device_detach:

		for (rc = 0; rc < GS_MAX_INTF; rc++) {

		for (rc = 0; rc < parent->channel_cnt; rc++) {

			if (parent->canch[rc])

				netif_device_detach(parent->canch[rc]->netdev);

		}
@@ -1460,17 +1456,19 @@ static int gs_usb_probe(struct usb_interface *intf, 
	icount = dconf.icount + 1;

	dev_info(&intf->dev, "Configuring for %u interfaces\n", icount);



	if (icount > GS_MAX_INTF) {

	if (icount > type_max(parent->channel_cnt)) {

		dev_err(&intf->dev,

			"Driver cannot handle more that %u CAN interfaces\n",

			GS_MAX_INTF);

			type_max(parent->channel_cnt));

		return -EINVAL;

	}



	parent = kzalloc(sizeof(*parent), GFP_KERNEL);

	parent = kzalloc(struct_size(parent, canch, icount), GFP_KERNEL);

	if (!parent)

		return -ENOMEM;



	parent->channel_cnt = icount;



	init_usb_anchor(&parent->rx_submitted);



	usb_set_intfdata(intf, parent);
@@ -1531,7 +1529,7 @@ static void gs_usb_disconnect(struct usb_interface *intf) 
		return;

	}



	for (i = 0; i < GS_MAX_INTF; i++)

	for (i = 0; i < parent->channel_cnt; i++)

		if (parent->canch[i])

			gs_destroy_candev(parent->canch[i]);