[PATCH v2 3/3] can: kvaser_pciefd: Continue parsing DMA buf after dropped RX

Axel Forsman
2025-05-13T15:10:17Z

Going bus-off on a channel doing RX could result in dropped packets.

As netif_running() gets cleared before the channel abort procedure,
the handling of any last RDATA packets would see netif_rx() return
non-zero to signal a dropped packet. kvaser_pciefd_read_buffer() dealt
with this "error" by breaking out of processing the remaining DMA RX
buffer.

Only return an error from kvaser_pciefd_read_buffer() due to packet
corruption, otherwise handle it internally.

Cc: stable@vger.kernel.org
Signed-off-by: Axel Forsman <axfo@kvaser.com>
Tested-by: Jimmy Assarsson <extja@kvaser.com>
Reviewed-by: Jimmy Assarsson <extja@kvaser.com>
---
drivers/net/can/kvaser_pciefd.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/kvaser_pciefd.c b/drivers/net/can/kvaser_pciefd.c
index 6cb657018cdf..6b3b04b5a4c2 100644
--- a/drivers/net/can/kvaser_pciefd.c
+++ b/drivers/net/can/kvaser_pciefd.c
@@ -1209,7 +1209,7 @@ static int kvaser_pciefd_handle_data_packet(struct kvaser_pciefd *pcie,
skb = alloc_canfd_skb(priv->dev, &cf);
if (!skb) {
priv->dev->stats.rx_dropped++;
- return -ENOMEM;
+ return 0;
}

cf->len = can_fd_dlc2len(dlc);
@@ -1221,7 +1221,7 @@ static int kvaser_pciefd_handle_data_packet(struct kvaser_pciefd *pcie,
skb = alloc_can_skb(priv->dev, (struct can_frame **)&cf);
if (!skb) {
priv->dev->stats.rx_dropped++;
- return -ENOMEM;
+ return 0;
}
can_frame_set_cc_len((struct can_frame *)cf, dlc, priv->ctrlmode);
}
@@ -1239,7 +1239,9 @@ static int kvaser_pciefd_handle_data_packet(struct kvaser_pciefd *pcie,
priv->dev->stats.rx_packets++;
kvaser_pciefd_set_skb_timestamp(pcie, skb, p->timestamp);

- return netif_rx(skb);
+ netif_rx(skb);
+
+ return 0;
}

static void kvaser_pciefd_change_state(struct kvaser_pciefd_can *can,
--
2.47.2