From: Simon Horman <horms+renesas@xxxxxxxxxxxx> Date: Mon, 10 Dec 2018 09:59:17 +0100 > +#define RAVB_CSUM_LEN 2 > + ... > priv->rx_buf_sz = (ndev->mtu <= 1492 ? PKT_BUF_SZ : ndev->mtu) + > - ETH_HLEN + VLAN_HLEN; > + ETH_HLEN + VLAN_HLEN + RAVB_CSUM_LEN; ... > + if (unlikely(skb->len < RAVB_CSUM_LEN)) ... > - hw_csum = skb_tail_pointer(skb) - 2; > + hw_csum = skb_tail_pointer(skb) - RAVB_CSUM_LEN; ... > - skb_trim(skb, skb->len - 2); > + skb_trim(skb, skb->len - RAVB_CSUM_LEN); Unlike Sergei, I think this macro define should be kept in the fix. It is absolutely crucial for anyone reading this code to understand what this value is all about. People reading the code aren't able to go automatically back to a commit to learn what this value means, and even if they could they shouldn't have to do so for a bunch of magic '2' constants placed all over. Even in the most fundamental way, the macro is required to satisfy the "no magic constants" rule for kernel code.
