[NET]: IP header modifier helpers annotations.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/dsfield.h b/include/net/dsfield.h
index dae8453..eb65bf2 100644
--- a/include/net/dsfield.h
+++ b/include/net/dsfield.h
@@ -27,7 +27,7 @@
 static inline void ipv4_change_dsfield(struct iphdr *iph,__u8 mask,
     __u8 value)
 {
-        __u32 check = ntohs(iph->check);
+        __u32 check = ntohs((__force __be16)iph->check);
 	__u8 dsfield;
 
 	dsfield = (iph->tos & mask) | value;
@@ -35,7 +35,7 @@
 	if ((check+1) >> 16) check = (check+1) & 0xffff;
 	check -= dsfield;
 	check += check >> 16; /* adjust carry */
-	iph->check = htons(check);
+	iph->check = (__force __sum16)htons(check);
 	iph->tos = dsfield;
 }