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, 3 insertions, 5 deletions

diff --git a/drivers/net/wireless/intersil/hostap/hostap_80211_rx.c b/drivers/net/wireless/intersil/hostap/hostap_80211_rx.c
index 34dbddbf3f9b..6d8b64ca1a63 100644
--- a/drivers/net/wireless/intersil/hostap/hostap_80211_rx.c
+++ b/drivers/net/wireless/intersil/hostap/hostap_80211_rx.c
@@ -131,8 +131,7 @@ int prism2_rx_80211(struct net_device *dev, struct sk_buff *skb,
 
 	if (prism_header == 1) {
 		struct linux_wlan_ng_prism_hdr *hdr;
-		hdr = (struct linux_wlan_ng_prism_hdr *)
-			skb_push(skb, phdrlen);
+		hdr = skb_push(skb, phdrlen);
 		memset(hdr, 0, phdrlen);
 		hdr->msgcode = LWNG_CAP_DID_BASE;
 		hdr->msglen = sizeof(*hdr);
@@ -153,8 +152,7 @@ hdr->f.status = s; hdr->f.len = l; hdr->f.data = d
 #undef LWNG_SETVAL
 	} else if (prism_header == 2) {
 		struct linux_wlan_ng_cap_hdr *hdr;
-		hdr = (struct linux_wlan_ng_cap_hdr *)
-			skb_push(skb, phdrlen);
+		hdr = skb_push(skb, phdrlen);
 		memset(hdr, 0, phdrlen);
 		hdr->version    = htonl(LWNG_CAPHDR_VERSION);
 		hdr->length     = htonl(phdrlen);
@@ -172,7 +170,7 @@ hdr->f.status = s; hdr->f.len = l; hdr->f.data = d
 		hdr->encoding   = htonl(1); /* cck */
 	} else if (prism_header == 3) {
 		struct hostap_radiotap_rx *hdr;
-		hdr = (struct hostap_radiotap_rx *)skb_push(skb, phdrlen);
+		hdr = skb_push(skb, phdrlen);
 		memset(hdr, 0, phdrlen);
 		hdr->hdr.it_len = cpu_to_le16(phdrlen);
 		hdr->hdr.it_present =