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authorPaolo Abeni <pabeni@redhat.com>2017-06-26 19:01:50 +0200
committerDavid S. Miller <davem@davemloft.net>2017-06-27 15:43:56 -0400
commitb26bbdae460ba90fb8cda37123a66be15a43a2a9 (patch)
tree0fb3d183d76a2858499075fe020735b2571a1406 /include/net/udp.h
parentd97af30f615eea23ecfefd0e80b2f5f2f41afe55 (diff)
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 <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/udp.h')
-rw-r--r--include/net/udp.h61
1 files changed, 61 insertions, 0 deletions
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
*/