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, 1 insertions, 1 deletions

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 022c0b5f9844..c6c0595d267b 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -383,7 +383,7 @@ static int vrf_finish_direct(struct net *net, struct sock *sk,
 
 	if (!list_empty(&vrf_dev->ptype_all) &&
 	    likely(skb_headroom(skb) >= ETH_HLEN)) {
-		struct ethhdr *eth = (struct ethhdr *)skb_push(skb, ETH_HLEN);
+		struct ethhdr *eth = skb_push(skb, ETH_HLEN);
 
 		ether_addr_copy(eth->h_source, vrf_dev->dev_addr);
 		eth_zero_addr(eth->h_dest);