4.18-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit d48051c5b8376038c2b287c3b1bd55b8d391d567 ]
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 pstaszewski@itcare.pl Signed-off-by: Eric Dumazet edumazet@google.com Cc: Eran Ben Elisha eranbe@mellanox.com Cc: Saeed Mahameed saeedm@mellanox.com Cc: Dimitris Michailidis dmichail@google.com Cc: Cong Wang xiyou.wangcong@gmail.com Cc: Paweł Staszewski pstaszewski@itcare.pl Reviewed-by: Eran Ben Elisha eranbe@mellanox.com Tested-By: Maria Pasechnik mariap@mellanox.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 45 ++++-------------------- 1 file changed, 9 insertions(+), 36 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c @@ -693,43 +693,15 @@ static inline bool is_last_ethertype_ip( return (ethertype == htons(ETH_P_IP) || ethertype == htons(ETH_P_IPV6)); }
-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; - - if (!skb_is_nonlinear(skb)) - return *(__be32 *)(skb->data + skb->len - ETH_FCS_LEN); - - 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]; + const void *fcs_bytes; + u32 _fcs_bytes;
- 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); + fcs_bytes = skb_header_pointer(skb, skb->len - ETH_FCS_LEN, + ETH_FCS_LEN, &_fcs_bytes);
- return fcs_bytes; + return __get_unaligned_cpu32(fcs_bytes); }
static inline void mlx5e_handle_csum(struct net_device *netdev, @@ -762,8 +734,9 @@ static inline void mlx5e_handle_csum(str 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; }