net: move secpath_exist helper to sk_buff.h

Future patch will remove skb->sp pointer.
To reduce noise in those patches, move existing helper to
sk_buff and use it in more places to ease skb->sp replacement later.

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

include/linux/skbuff.h

@@ -4097,12 +4097,19 @@ static inline void skb_init_secmark(struct sk_buff *skb)
 { }
 #endif
 
+static inline int secpath_exists(const struct sk_buff *skb)
+{
+#ifdef CONFIG_XFRM
+	return skb->sp != NULL;
+#else
+	return 0;
+#endif
+}
+
 static inline bool skb_irq_freeable(const struct sk_buff *skb)
 {
 	return !skb->destructor &&
-#if IS_ENABLED(CONFIG_XFRM)
+		!secpath_exists(skb) &&
-		!skb->sp &&
-#endif
 		!skb_nfct(skb) &&
 		!skb->_skb_refdst &&
 		!skb_has_frag_list(skb);

include/net/xfrm.h

@@ -1107,15 +1107,6 @@ struct sec_path {
 	struct xfrm_offload	ovec[XFRM_MAX_OFFLOAD_DEPTH];
 };
 
-static inline int secpath_exists(struct sk_buff *skb)
-{
-#ifdef CONFIG_XFRM
-	return skb->sp != NULL;
-#else
-	return 0;
-#endif
-}
-
 static inline struct sec_path *
 secpath_get(struct sec_path *sp)
 {

net/netfilter/nft_meta.c

@@ -229,7 +229,7 @@ void nft_meta_get_eval(const struct nft_expr *expr,
 	}
 #ifdef CONFIG_XFRM
 	case NFT_META_SECPATH:
-		nft_reg_store8(dest, !!skb->sp);
+		nft_reg_store8(dest, secpath_exists(skb));
 		break;
 #endif
 #ifdef CONFIG_NF_TABLES_BRIDGE