From b26bbdae460ba90fb8cda37123a66be15a43a2a9 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Mon, 26 Jun 2017 19:01:50 +0200 Subject: udp: move scratch area helpers into the include file So that they can be later used by the IPv6 code, too. Also lift the comments a bit. Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller --- include/net/udp.h | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) (limited to 'include/net/udp.h') diff --git a/include/net/udp.h b/include/net/udp.h index 1468dbd0f09a..972ce4baab6b 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -302,6 +302,67 @@ struct sock *__udp6_lib_lookup(struct net *net, struct sock *udp6_lib_lookup_skb(struct sk_buff *skb, __be16 sport, __be16 dport); +/* UDP uses skb->dev_scratch to cache as much information as possible and avoid + * possibly multiple cache miss on dequeue() + */ +#if BITS_PER_LONG == 64 + +/* truesize, len and the bit needed to compute skb_csum_unnecessary will be on + * cold cache lines at recvmsg time. + * skb->len can be stored on 16 bits since the udp header has been already + * validated and pulled. + */ +struct udp_dev_scratch { + u32 truesize; + u16 len; + bool is_linear; + bool csum_unnecessary; +}; + +static inline unsigned int udp_skb_len(struct sk_buff *skb) +{ + return ((struct udp_dev_scratch *)&skb->dev_scratch)->len; +} + +static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) +{ + return ((struct udp_dev_scratch *)&skb->dev_scratch)->csum_unnecessary; +} + +static inline bool udp_skb_is_linear(struct sk_buff *skb) +{ + return ((struct udp_dev_scratch *)&skb->dev_scratch)->is_linear; +} + +#else +static inline unsigned int udp_skb_len(struct sk_buff *skb) +{ + return skb->len; +} + +static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb) +{ + return skb_csum_unnecessary(skb); +} + +static inline bool udp_skb_is_linear(struct sk_buff *skb) +{ + return !skb_is_nonlinear(skb); +} +#endif + +static inline int copy_linear_skb(struct sk_buff *skb, int len, int off, + struct iov_iter *to) +{ + int n, copy = len - off; + + n = copy_to_iter(skb->data + off, copy, to); + if (n == copy) + return 0; + + return -EFAULT; +} + /* * SNMP statistics for UDP and UDP-Lite */ -- cgit v1.2.3-58-ga151