[PATCH 5.10 27/38] drivers: net: xgene: Fix regression in CRC stripping

Greg Kroah-Hartman
2022-03-25T15:17:05Z

From: Stephane Graber <stgraber@ubuntu.com>

commit e9e6faeafaa00da1851bcf47912b0f1acae666b4 upstream.

All packets on ingress (except for jumbo) are terminated with a 4-bytes
CRC checksum. It's the responsability of the driver to strip those 4
bytes. Unfortunately a change dating back to March 2017 re-shuffled some
code and made the CRC stripping code effectively dead.

This change re-orders that part a bit such that the datalen is
immediately altered if needed.

Fixes: 4902a92270fb ("drivers: net: xgene: Add workaround for errata 10GE_8/ENET_11")
Cc: stable@vger.kernel.org
Signed-off-by: Stephane Graber <stgraber@ubuntu.com>
Tested-by: Stephane Graber <stgraber@ubuntu.com>
Link: https://lore.kernel.org/r/20220322224205.752795-1-stgraber@ubuntu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/apm/xgene/xgene_enet_main.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

--- a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
+++ b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
@@ -696,6 +696,12 @@ static int xgene_enet_rx_frame(struct xg
buf_pool->rx_skb[skb_index] = NULL;

datalen = xgene_enet_get_data_len(le64_to_cpu(raw_desc->m1));
+
+ /* strip off CRC as HW isn't doing this */
+ nv = GET_VAL(NV, le64_to_cpu(raw_desc->m0));
+ if (!nv)
+ datalen -= 4;
+
skb_put(skb, datalen);
prefetch(skb->data - NET_IP_ALIGN);
skb->protocol = eth_type_trans(skb, ndev);
@@ -717,12 +723,8 @@ static int xgene_enet_rx_frame(struct xg
}
}

- nv = GET_VAL(NV, le64_to_cpu(raw_desc->m0));
- if (!nv) {
- /* strip off CRC as HW isn't doing this */
- datalen -= 4;
+ if (!nv)
goto skip_jumbo;
- }

slots = page_pool->slots - 1;
head = page_pool->head;