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, 2 insertions, 2 deletions

diff --git a/net/decnet/dn_dev.c b/net/decnet/dn_dev.c
index 1d84f6dae315..fa0110b57ca1 100644
--- a/net/decnet/dn_dev.c
+++ b/net/decnet/dn_dev.c
@@ -867,7 +867,7 @@ static void dn_send_endnode_hello(struct net_device *dev, struct dn_ifaddr *ifa)
 	msg->datalen = 0x02;
 	memset(msg->data, 0xAA, 2);
 
-	pktlen = (__le16 *)skb_push(skb,2);
+	pktlen = skb_push(skb, 2);
 	*pktlen = cpu_to_le16(skb->len - 2);
 
 	skb_reset_network_header(skb);
@@ -959,7 +959,7 @@ static void dn_send_router_hello(struct net_device *dev, struct dn_ifaddr *ifa)
 
 	skb_trim(skb, (27 + *i2));
 
-	pktlen = (__le16 *)skb_push(skb, 2);
+	pktlen = skb_push(skb, 2);
 	*pktlen = cpu_to_le16(skb->len - 2);
 
 	skb_reset_network_header(skb);