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, 2 deletions

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index 84de7b6326dc..2cf9d59f1b72 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -322,8 +322,7 @@ static int afiucv_hs_send(struct iucv_message *imsg, struct sock *sock,
 	int err, confirm_recv = 0;
 
 	memset(skb->head, 0, ETH_HLEN);
-	phs_hdr = (struct af_iucv_trans_hdr *)skb_push(skb,
-					sizeof(struct af_iucv_trans_hdr));
+	phs_hdr = skb_push(skb, sizeof(struct af_iucv_trans_hdr));
 	skb_reset_mac_header(skb);
 	skb_reset_network_header(skb);
 	skb_push(skb, ETH_HLEN);