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>

5 files changed, 8 insertions, 8 deletions

diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 2ede4e459c4e..d8b40ff4b2e6 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -538,7 +538,7 @@ static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
 	 * decryption.
 	 */
 	if ((x->props.flags & XFRM_STATE_ESN)) {
-		esph = (void *)skb_push(skb, 4);
+		esph = skb_push(skb, 4);
 		*seqhi = esph->spi;
 		esph->spi = esph->seq_no;
 		esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
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;
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 64eea3962733..e0e726c338a7 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -942,7 +942,7 @@ static int ip6gre_header(struct sk_buff *skb, struct net_device *dev,
 			const void *daddr, const void *saddr, unsigned int len)
 {
 	struct ip6_tnl *t = netdev_priv(dev);
-	struct ipv6hdr *ipv6h = (struct ipv6hdr *)skb_push(skb, t->hlen);
+	struct ipv6hdr *ipv6h = skb_push(skb, t->hlen);
 	__be16 *p = (__be16 *)(ipv6h+1);
 
 	ip6_flow_hdr(ipv6h, 0,
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 0d6f3b6345de..8b8efb0e55bf 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -682,7 +682,7 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 		skb_frag_list_init(skb);
 
 		__skb_pull(skb, hlen);
-		fh = (struct frag_hdr *)__skb_push(skb, sizeof(struct frag_hdr));
+		fh = __skb_push(skb, sizeof(struct frag_hdr));
 		__skb_push(skb, hlen);
 		skb_reset_network_header(skb);
 		memcpy(skb_network_header(skb), tmp_hdr, hlen);
@@ -706,7 +706,7 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 			if (frag) {
 				frag->ip_summed = CHECKSUM_NONE;
 				skb_reset_transport_header(frag);
-				fh = (struct frag_hdr *)__skb_push(frag, sizeof(struct frag_hdr));
+				fh = __skb_push(frag, sizeof(struct frag_hdr));
 				__skb_push(frag, hlen);
 				skb_reset_network_header(frag);
 				memcpy(skb_network_header(frag), tmp_hdr,
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 84ad50218255..6264917fe4c7 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -789,7 +789,7 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32
 
 	skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 
-	t1 = (struct tcphdr *) skb_push(buff, tot_len);
+	t1 = skb_push(buff, tot_len);
 	skb_reset_transport_header(buff);
 
 	/* Swap the send and the receive. */