drivers/net: avoid some skb->ip_summed initializations

fresh skbs have ip_summed set to CHECKSUM_NONE (0)

We can avoid setting again skb->ip_summed to CHECKSUM_NONE in drivers.

Introduce skb_checksum_none_assert() helper so that we keep this
assertion documented in driver sources.

Change most occurrences of :

skb->ip_summed = CHECKSUM_NONE;

by :

skb_checksum_none_assert(skb);

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index f900ffcd847e..9e8085a89589 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2206,6 +2206,21 @@ static inline void skb_forward_csum(struct sk_buff *skb)
                 skb->ip_summed = CHECKSUM_NONE;
 }
 
+/**
+ * skb_checksum_none_assert - make sure skb ip_summed is CHECKSUM_NONE
+ * @skb: skb to check
+ *
+ * fresh skbs have their ip_summed set to CHECKSUM_NONE.
+ * Instead of forcing ip_summed to CHECKSUM_NONE, we can
+ * use this helper, to document places where we make this assertion.
+ */
+static inline void skb_checksum_none_assert(struct sk_buff *skb)
+{
+#ifdef DEBUG
+        BUG_ON(skb->ip_summed != CHECKSUM_NONE);
+#endif
+}
+
 bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
 #endif  /* __KERNEL__ */
 #endif  /* _LINUX_SKBUFF_H */