As shown by Dmitris, we need to use csum_block_add() instead of csum_add()
when adding the FCS contribution to skb csum.
Before 4.18 (more exactly commit 88078d98d1bb "net: pskb_trim_rcsum()
and CHECKSUM_COMPLETE are friends"), the whole skb csum was thrown away,
so RXFCS changes were ignored.
Then before commit d55bef5059dd ("net: fix pskb_trim_rcsum_slow() with
odd trim offset") both mlx5 and pskb_trim_rcsum_slow() bugs were canceling
each other.
Now we fixed pskb_trim_rcsum_slow() we need to fix mlx5.
Note that this patch also rewrites mlx5e_get_fcs() to :
- Use skb_header_pointer() instead of reinventing it.
- Use __get_unaligned_cpu32() to avoid possible non aligned accesses
as Dmitris pointed out.
Fixes: 902a545904c7 ("net/mlx5e: When RXFCS is set, add FCS data into checksum
calculation")
Reported-by: Paweł Staszewski <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Cc: Eran Ben Elisha <[email protected]>
Cc: Saeed Mahameed <[email protected]>
Cc: Dimitris Michailidis <[email protected]>
Cc: Cong Wang <[email protected]>
Cc: Paweł Staszewski <[email protected]>
---
.../net/ethernet/mellanox/mlx5/core/en_rx.c | 45 ++++---------------
1 file changed, 9 insertions(+), 36 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index
94224c22ecc310a87b6715051e335446f29bec03..79638dcbae78395fb723c9bf3fa877e7a42d91cd
100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -713,43 +713,15 @@ static inline void mlx5e_enable_ecn(struct mlx5e_rq *rq,
struct sk_buff *skb)
rq->stats->ecn_mark += !!rc;
}
-static __be32 mlx5e_get_fcs(struct sk_buff *skb)
+static u32 mlx5e_get_fcs(const struct sk_buff *skb)
{
- int last_frag_sz, bytes_in_prev, nr_frags;
- u8 *fcs_p1, *fcs_p2;
- skb_frag_t *last_frag;
- __be32 fcs_bytes;
+ const void *fcs_bytes;
+ u32 _fcs_bytes;
- if (!skb_is_nonlinear(skb))
- return *(__be32 *)(skb->data + skb->len - ETH_FCS_LEN);
+ fcs_bytes = skb_header_pointer(skb, skb->len - ETH_FCS_LEN,
+ ETH_FCS_LEN, &_fcs_bytes);
- nr_frags = skb_shinfo(skb)->nr_frags;
- last_frag = &skb_shinfo(skb)->frags[nr_frags - 1];
- last_frag_sz = skb_frag_size(last_frag);
-
- /* If all FCS data is in last frag */
- if (last_frag_sz >= ETH_FCS_LEN)
- return *(__be32 *)(skb_frag_address(last_frag) +
- last_frag_sz - ETH_FCS_LEN);
-
- fcs_p2 = (u8 *)skb_frag_address(last_frag);
- bytes_in_prev = ETH_FCS_LEN - last_frag_sz;
-
- /* Find where the other part of the FCS is - Linear or another frag */
- if (nr_frags == 1) {
- fcs_p1 = skb_tail_pointer(skb);
- } else {
- skb_frag_t *prev_frag = &skb_shinfo(skb)->frags[nr_frags - 2];
-
- fcs_p1 = skb_frag_address(prev_frag) +
- skb_frag_size(prev_frag);
- }
- fcs_p1 -= bytes_in_prev;
-
- memcpy(&fcs_bytes, fcs_p1, bytes_in_prev);
- memcpy(((u8 *)&fcs_bytes) + bytes_in_prev, fcs_p2, last_frag_sz);
-
- return fcs_bytes;
+ return __get_unaligned_cpu32(fcs_bytes);
}
static u8 get_ip_proto(struct sk_buff *skb, __be16 proto)
@@ -797,8 +769,9 @@ static inline void mlx5e_handle_csum(struct net_device
*netdev,
network_depth - ETH_HLEN,
skb->csum);
if (unlikely(netdev->features & NETIF_F_RXFCS))
- skb->csum = csum_add(skb->csum,
- (__force
__wsum)mlx5e_get_fcs(skb));
+ skb->csum = csum_block_add(skb->csum,
+ (__force
__wsum)mlx5e_get_fcs(skb),
+ skb->len - ETH_FCS_LEN);
stats->csum_complete++;
return;
}
--
2.19.1.568.g152ad8e336-goog
