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>

3 files changed, 4 insertions, 6 deletions

diff --git a/drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c b/drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c
index 35fe991dcc56..55198ac2b755 100644
--- a/drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c
+++ b/drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c
@@ -278,8 +278,7 @@ static void rtl8187_tx(struct ieee80211_hw *dev,
 	}
 
 	if (!priv->is_rtl8187b) {
-		struct rtl8187_tx_hdr *hdr =
-			(struct rtl8187_tx_hdr *)skb_push(skb, sizeof(*hdr));
+		struct rtl8187_tx_hdr *hdr = skb_push(skb, sizeof(*hdr));
 		hdr->flags = cpu_to_le32(flags);
 		hdr->len = 0;
 		hdr->rts_duration = rts_dur;
@@ -292,8 +291,7 @@ static void rtl8187_tx(struct ieee80211_hw *dev,
 		unsigned int epmap[4] = { 6, 7, 5, 4 };
 		u16 fc = le16_to_cpu(tx_hdr->frame_control);
 
-		struct rtl8187b_tx_hdr *hdr =
-			(struct rtl8187b_tx_hdr *)skb_push(skb, sizeof(*hdr));
+		struct rtl8187b_tx_hdr *hdr = skb_push(skb, sizeof(*hdr));
 		struct ieee80211_rate *txrate =
 			ieee80211_get_tx_rate(dev, info);
 		memset(hdr, 0, sizeof(*hdr));
diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
index 39d56313bc94..21e5ef021260 100644
--- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
+++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
@@ -4952,7 +4952,7 @@ static void rtl8xxxu_tx(struct ieee80211_hw *hw,
 	if (control && control->sta)
 		sta = control->sta;
 
-	tx_desc = (struct rtl8xxxu_txdesc32 *)skb_push(skb, tx_desc_size);
+	tx_desc = skb_push(skb, tx_desc_size);
 
 	memset(tx_desc, 0, tx_desc_size);
 	tx_desc->pkt_size = cpu_to_le16(pktlen);
diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
index 41422e4da8b7..de6c3428f7c6 100644
--- a/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192cu/trx.c
@@ -512,7 +512,7 @@ void rtl92cu_tx_fill_desc(struct ieee80211_hw *hw,
 
 	seq_number = (le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_SEQ) >> 4;
 	rtl_get_tcb_desc(hw, info, sta, skb, tcb_desc);
-	txdesc = (u8 *)skb_push(skb, RTL_TX_HEADER_SIZE);
+	txdesc = skb_push(skb, RTL_TX_HEADER_SIZE);
 	memset(txdesc, 0, RTL_TX_HEADER_SIZE);
 	SET_TX_DESC_PKT_SIZE(txdesc, pktlen);
 	SET_TX_DESC_LINIP(txdesc, 0);