[PATCH] can: gs_usb: gs_usb_receive_bulk_callback(): resubmit URB on skb allocation failure

[Marc Kleine-Budde]

If the allocation of the SKB in gs_usb_receive_bulk_callback() fails, the
driver returns from the callback without resubmitting the URB in order to
receive further USB in URBs.

This results in a silent performance degradation which, if it occurs
repeatedly, results in starvation of USB in traffic.

Instead of returning immediately, try to resend the URB. If this also
fails, this is logged as an info message.

Fixes: d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices")
Fixes: 26949ac935e3 ("can: gs_usb: add CAN-FD support")
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
---
 drivers/net/can/usb/gs_usb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
index ec9a7cbbbc69..82508a865095 100644
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -674,7 +674,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 		if (hf->flags & GS_CAN_FLAG_FD) {
 			skb = alloc_canfd_skb(netdev, &cfd);
 			if (!skb)
-				return;
+				goto resubmit_urb;
 
 			cfd->can_id = le32_to_cpu(hf->can_id);
 			cfd->len = data_length;
@@ -687,7 +687,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 		} else {
 			skb = alloc_can_skb(netdev, &cf);
 			if (!skb)
-				return;
+				goto resubmit_urb;
 
 			cf->can_id = le32_to_cpu(hf->can_id);
 			can_frame_set_cc_len(cf, hf->can_dlc, dev->can.ctrlmode);

---
base-commit: 60444706aa17616efc03190d099ac347e28b3d0a
change-id: 20260709-gs_usb-resubmit-urb-ad08a707488e

Best regards,
--  
Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>