[net-next PATCH 05/11] net: ravb: Simplify types in RX csum validation

Paul Barker
2024-09-30T16:09:26Z

From: Paul Barker <paul.barker.ct@bp.renesas.com>

The HW checksum value is used as a 16-bit flag, it is zero when the
checksum has been validated and non-zero otherwise. Therefore we don't
need to treat this as an actual __wsum type or call csum_unfold(), we
can just use a u16 pointer.

Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>
---
drivers/net/ethernet/renesas/ravb_main.c | 30 +++++++++++-------------
1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 1dd2152734b0..9350ca10ab22 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -749,12 +749,11 @@ static void ravb_get_tx_tstamp(struct net_device *ndev)
static void ravb_rx_csum_gbeth(struct sk_buff *skb)
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
- __wsum csum_proto;
- skb_frag_t *last_frag;
- u8 *hw_csum;
+ size_t csum_len;
+ u16 *hw_csum;

- /* The hardware checksum status is contained in sizeof(__sum16) * 2 = 4
- * bytes appended to packet data.
+ /* The hardware checksum status is contained in 4 bytes appended to
+ * packet data.
*
* For ipv4, the first 2 bytes are the ip header checksum status. We can
* ignore this as it will always be re-checked in inet_gro_receive().
@@ -762,23 +761,22 @@ static void ravb_rx_csum_gbeth(struct sk_buff *skb)
* The last 2 bytes are the protocol checksum status which will be zero
* if the checksum has been validated.
*/
- if (unlikely(skb->len < sizeof(__sum16) * 2))
+ csum_len = sizeof(*hw_csum) * 2;
+ if (unlikely(skb->len < csum_len))
return;

if (skb_is_nonlinear(skb)) {
- last_frag = &shinfo->frags[shinfo->nr_frags - 1];
- hw_csum = skb_frag_address(last_frag) +
- skb_frag_size(last_frag);
- skb_frag_size_sub(last_frag, 2 * sizeof(__sum16));
+ skb_frag_t *last_frag = &shinfo->frags[shinfo->nr_frags - 1];
+
+ hw_csum = (u16 *)(skb_frag_address(last_frag) +
+ skb_frag_size(last_frag));
+ skb_frag_size_sub(last_frag, csum_len);
} else {
- hw_csum = skb_tail_pointer(skb);
- skb_trim(skb, skb->len - 2 * sizeof(__sum16));
+ hw_csum = (u16 *)skb_tail_pointer(skb);
+ skb_trim(skb, skb->len - csum_len);
}

- hw_csum -= sizeof(__sum16);
- csum_proto = csum_unfold((__force __sum16)get_unaligned_le16(hw_csum));
-
- if (!csum_proto)
+ if (!*--hw_csum)
skb->ip_summed = CHECKSUM_UNNECESSARY;
}

--
2.43.0