can: gs_usb: increase max interface to U8_MAX

commit 2a27f6a8fb5722223d526843040f747e9b0e8060 upstream

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: d08e973a77 ("can: gs_usb: Added support for the GS_USB CAN devices")
Reported-by: Runcheng Lu <runcheng.lu@hpmicro.com>
Cc: stable@vger.kernel.org
Reviewed-by: Vincent Mailhol <mailhol@kernel.org>
Signed-off-by: Celeste Liu <uwu@coelacanthus.name>
Link: https://patch.msgid.link/20250930-gs-usb-max-if-v5-1-863330bf6666@coelacanthus.name
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Celeste Liu 2025-10-27 21:11:57 +08:00 • committed by Greg Kroah-Hartman
commit 12afe2c625

View file

@ -156,10 +156,6 @@ struct gs_host_frame {
#define GS_MAX_TX_URBS 10
/* Only launch a max of GS_MAX_RX_URBS usb requests at a time. */
#define GS_MAX_RX_URBS 30
/* Maximum number of interfaces the driver supports per device.
* Current hardware only supports 2 interfaces. The future may vary.
*/
#define GS_MAX_INTF 2
struct gs_tx_context {
struct gs_can *dev;
@ -190,10 +186,11 @@ 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;
u8 active_channels;
u8 channel_cnt;
struct gs_can *canch[];
};
/* 'allocate' a tx context.
@ -321,7 +318,7 @@ 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 >= usbcan->channel_cnt)
goto device_detach;
dev = usbcan->canch[hf->channel];
@ -409,7 +406,7 @@ 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 < usbcan->channel_cnt; rc++) {
if (usbcan->canch[rc])
netif_device_detach(usbcan->canch[rc]->netdev);
}
@ -991,20 +988,22 @@ static int gs_usb_probe(struct usb_interface *intf,
icount = dconf->icount + 1;
dev_info(&intf->dev, "Configuring for %d interfaces\n", icount);
if (icount > GS_MAX_INTF) {
if (icount > type_max(typeof(dev->channel_cnt))) {
dev_err(&intf->dev,
"Driver cannot handle more that %d CAN interfaces\n",
GS_MAX_INTF);
"Driver cannot handle more that %u CAN interfaces\n",
type_max(typeof(dev->channel_cnt)));
kfree(dconf);
return -EINVAL;
}
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
dev = kzalloc(struct_size(dev, canch, icount), GFP_KERNEL);
if (!dev) {
kfree(dconf);
return -ENOMEM;
}
dev->channel_cnt = icount;
init_usb_anchor(&dev->rx_submitted);
usb_set_intfdata(intf, dev);
@ -1045,7 +1044,7 @@ static void gs_usb_disconnect(struct usb_interface *intf)
return;
}
for (i = 0; i < GS_MAX_INTF; i++)
for (i = 0; i < dev->channel_cnt; i++)
if (dev->canch[i])
gs_destroy_candev(dev->canch[i]);