[PATCH 6.1.y] can: gs_usb: gs_usb_receive_bulk_callback(): resubmit URB on skb allocation failure

From: Marc Kleine-Budde <[email protected]>

[ Upstream commit 68c5724ecd159992f76edb7b57dc508a44c8b7da ]

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")
Link: https://patch.msgid.link/[email protected]
Cc: [email protected]
Signed-off-by: Marc Kleine-Budde <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 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 220496b76cd94..3ce8cf4ecb2e5 100644
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -574,7 +574,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 		if (hf->flags & GS_CAN_FLAG_FD) {
 			skb = alloc_canfd_skb(dev->netdev, &cfd);
 			if (!skb)
-				return;
+				goto resubmit_urb;
 
 			cfd->can_id = le32_to_cpu(hf->can_id);
 			cfd->len = can_fd_dlc2len(hf->can_dlc);
@@ -587,7 +587,7 @@ static void gs_usb_receive_bulk_callback(struct urb *urb)
 		} else {
 			skb = alloc_can_skb(dev->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);
-- 
2.53.0