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/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 7418088..c8852ac 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -848,7 +848,7 @@ static void mac80211_hwsim_monitor_rx(struct ieee80211_hw *hw,
 	if (skb == NULL)
 		return;
 
-	hdr = (struct hwsim_radiotap_hdr *) skb_push(skb, sizeof(*hdr));
+	hdr = skb_push(skb, sizeof(*hdr));
 	hdr->hdr.it_version = PKTHDR_RADIOTAP_VERSION;
 	hdr->hdr.it_pad = 0;
 	hdr->hdr.it_len = cpu_to_le16(sizeof(*hdr));
@@ -1146,7 +1146,7 @@ static void mac80211_hwsim_add_vendor_rtap(struct sk_buff *skb)
 	 * Note that this code requires the headroom in the SKB
 	 * that was allocated earlier.
 	 */
-	rtap = (void *)skb_push(skb, sizeof(*rtap) + 8 + 4);
+	rtap = skb_push(skb, sizeof(*rtap) + 8 + 4);
 	rtap->oui[0] = HWSIM_RADIOTAP_OUI[0];
 	rtap->oui[1] = HWSIM_RADIOTAP_OUI[1];
 	rtap->oui[2] = HWSIM_RADIOTAP_OUI[2];