net: switch secpath to use skb extension infrastructure

Remove skb->sp and allocate secpath storage via extension
infrastructure.  This also reduces sk_buff by 8 bytes on x86_64.

Total size of allyesconfig kernel is reduced slightly, as there is
less inlined code (one conditional atomic op instead of two on
skb_clone).

No differences in throughput in following ipsec performance tests:
- transport mode with aes on 10GB link
- tunnel mode between two network namespaces with aes and null cipher

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 6 insertions, 26 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index d0f254a016bf..3f741b04e55d 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -714,9 +714,6 @@ struct sk_buff {
 		struct list_head	tcp_tsorted_anchor;
 	};
 
-#ifdef CONFIG_XFRM
-	struct	sec_path	*sp;
-#endif
 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 	unsigned long		 _nfct;
 #endif
@@ -3908,6 +3905,9 @@ enum skb_ext_id {
 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 	SKB_EXT_BRIDGE_NF,
 #endif
+#ifdef CONFIG_XFRM
+	SKB_EXT_SEC_PATH,
+#endif
 	SKB_EXT_NUM, /* must be last */
 };
 
@@ -4069,7 +4069,7 @@ static inline void skb_init_secmark(struct sk_buff *skb)
 static inline int secpath_exists(const struct sk_buff *skb)
 {
 #ifdef CONFIG_XFRM
-	return skb->sp != NULL;
+	return skb_ext_exist(skb, SKB_EXT_SEC_PATH);
 #else
 	return 0;
 #endif
@@ -4127,7 +4127,7 @@ static inline bool skb_get_dst_pending_confirm(const struct sk_buff *skb)
 static inline struct sec_path *skb_sec_path(const struct sk_buff *skb)
 {
 #ifdef CONFIG_XFRM
-	return skb->sp;
+	return skb_ext_find(skb, SKB_EXT_SEC_PATH);
 #else
 	return NULL;
 #endif
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 31220edcce95..38c232861a64 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1096,7 +1096,6 @@ struct xfrm_offload {
 };
 
 struct sec_path {
-	refcount_t		refcnt;
 	int			len;
 	int			olen;
 
@@ -1104,32 +1103,13 @@ struct sec_path {
 	struct xfrm_offload	ovec[XFRM_MAX_OFFLOAD_DEPTH];
 };
 
-static inline struct sec_path *
-secpath_get(struct sec_path *sp)
-{
-	if (sp)
-		refcount_inc(&sp->refcnt);
-	return sp;
-}
-
-void __secpath_destroy(struct sec_path *sp);
-
-static inline void
-secpath_put(struct sec_path *sp)
-{
-	if (sp && refcount_dec_and_test(&sp->refcnt))
-		__secpath_destroy(sp);
-}
-
-struct sec_path *secpath_dup(struct sec_path *src);
 struct sec_path *secpath_set(struct sk_buff *skb);
 
 static inline void
 secpath_reset(struct sk_buff *skb)
 {
 #ifdef CONFIG_XFRM
-	secpath_put(skb->sp);
-	skb->sp = NULL;
+	skb_ext_del(skb, SKB_EXT_SEC_PATH);
 #endif
 }