seg6_iptunnel: Refactor seg6_lwt_headroom out of uapi header

Refactor the function seg6_lwt_headroom out of the seg6_iptunnel.h uapi
header, because it is only used in seg6_iptunnel.c. Moreover, it is only
used in the kernel code, as indicated by the "#ifdef __KERNEL__".
Suggested-by: NDavid Miller <davem@davemloft.net>
Signed-off-by: NIoana-Ruxandra Stăncioi <stancioi@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/uapi/linux/seg6_iptunnel.h

@@ -37,25 +37,4 @@ enum {
 	SEG6_IPTUN_MODE_L2ENCAP,
 };
 
-#ifdef __KERNEL__
-
-static inline size_t seg6_lwt_headroom(struct seg6_iptunnel_encap *tuninfo)
-{
-	int head = 0;
-
-	switch (tuninfo->mode) {
-	case SEG6_IPTUN_MODE_INLINE:
-		break;
-	case SEG6_IPTUN_MODE_ENCAP:
-		head = sizeof(struct ipv6hdr);
-		break;
-	case SEG6_IPTUN_MODE_L2ENCAP:
-		return 0;
-	}
-
-	return ((tuninfo->srh->hdrlen + 1) << 3) + head;
-}
-
-#endif
-
 #endif

net/ipv6/seg6_iptunnel.c

@@ -27,6 +27,23 @@
 #include <net/seg6_hmac.h>
 #endif
 
+static size_t seg6_lwt_headroom(struct seg6_iptunnel_encap *tuninfo)
+{
+	int head = 0;
+
+	switch (tuninfo->mode) {
+	case SEG6_IPTUN_MODE_INLINE:
+		break;
+	case SEG6_IPTUN_MODE_ENCAP:
+		head = sizeof(struct ipv6hdr);
+		break;
+	case SEG6_IPTUN_MODE_L2ENCAP:
+		return 0;
+	}
+
+	return ((tuninfo->srh->hdrlen + 1) << 3) + head;
+}
+
 struct seg6_lwt {
 	struct dst_cache cache;
 	struct seg6_iptunnel_encap tuninfo[];