networking: make skb_push & __skb_push return void pointers

It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.

Make these functions return void * and remove all the casts across
the tree, adding a (u8 *) cast only where the unsigned char pointer
was used directly, all done with the following spatch:

    @@
    expression SKB, LEN;
    typedef u8;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    @@
    - *(fn(SKB, LEN))
    + *(u8 *)fn(SKB, LEN)

    @@
    expression E, SKB, LEN;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    type T;
    @@
    - E = ((T *)(fn(SKB, LEN)))
    + E = fn(SKB, LEN)

    @@
    expression SKB, LEN;
    identifier fn = { skb_push, __skb_push, skb_push_rcsum };
    @@
    - fn(SKB, LEN)[0]
    + *(u8 *)fn(SKB, LEN)

Note that the last part there converts from push(...)[0] to the
more idiomatic *(u8 *)push(...).

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index b636f1da9aec..0460af226011 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -847,7 +847,7 @@ static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
 
 	ihdr = (struct rt0_hdr *) opt;
 
-	phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
+	phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
 	memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
 
 	hops = ihdr->rt_hdr.hdrlen >> 1;
@@ -873,7 +873,7 @@ static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
 	sr_ihdr = (struct ipv6_sr_hdr *)opt;
 	plen = (sr_ihdr->hdrlen + 1) << 3;
 
-	sr_phdr = (struct ipv6_sr_hdr *)skb_push(skb, plen);
+	sr_phdr = skb_push(skb, plen);
 	memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
 
 	hops = sr_ihdr->first_segment + 1;
@@ -923,7 +923,7 @@ static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
 
 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
 {
-	struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
+	struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
 
 	memcpy(h, opt, ipv6_optlen(opt));
 	h->nexthdr = *proto;