skbuff: make __skb_header_pointer()'s data argument const

The function never modifies the input buffer, so 'data' argument
can be marked as const.
This implies one harmless cast-away.

Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 483e89348f78b48235748de37ae3ea7ec9450491..d6ea3dc3eddb2793d51530230f89faa7feacff58 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3678,11 +3678,11 @@ __wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
                    __wsum csum);
 
 static inline void * __must_check
-__skb_header_pointer(const struct sk_buff *skb, int offset,
-                    int len, void *data, int hlen, void *buffer)
+__skb_header_pointer(const struct sk_buff *skb, int offset, int len,
+                    const void *data, int hlen, void *buffer)
 {
        if (hlen - offset >= len)
-               return data + offset;
+               return (void *)data + offset;
 
        if (!skb ||
            skb_copy_bits(skb, offset, buffer, len) < 0)