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/802/fc.c b/net/802/fc.c
index 1bb496ea997e..058a9f708918 100644
--- a/net/802/fc.c
+++ b/net/802/fc.c
@@ -49,7 +49,7 @@ static int fc_header(struct sk_buff *skb, struct net_device *dev,
 		struct fcllc *fcllc;
 
 		hdr_len = sizeof(struct fch_hdr) + sizeof(struct fcllc);
-		fch = (struct fch_hdr *)skb_push(skb, hdr_len);
+		fch = skb_push(skb, hdr_len);
 		fcllc = (struct fcllc *)(fch+1);
 		fcllc->dsap = fcllc->ssap = EXTENDED_SAP;
 		fcllc->llc = UI_CMD;
@@ -59,7 +59,7 @@ static int fc_header(struct sk_buff *skb, struct net_device *dev,
 	else
 	{
 		hdr_len = sizeof(struct fch_hdr);
-		fch = (struct fch_hdr *)skb_push(skb, hdr_len);
+		fch = skb_push(skb, hdr_len);
 	}
 
 	if(saddr)