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: d08e973a77d1 ("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@coelacanth... Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de --- drivers/net/can/usb/gs_usb.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-)
diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c index 7dc4fb574e45..33800bb75064 100644 --- a/drivers/net/can/usb/gs_usb.c +++ b/drivers/net/can/usb/gs_usb.c @@ -157,10 +157,6 @@ 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; @@ -191,10 +187,11 @@ 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[] __counted_by(channel_cnt); };
/* 'allocate' a tx context. @@ -322,7 +319,7 @@ 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]; @@ -410,7 +407,7 @@ 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); } @@ -993,20 +990,22 @@ 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); @@ -1047,7 +1046,7 @@ 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]);