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/nfc/st21nfca/i2c.c b/drivers/nfc/st21nfca/i2c.c
index c36f0e0afdfd..396cdafb3e36 100644
--- a/drivers/nfc/st21nfca/i2c.c
+++ b/drivers/nfc/st21nfca/i2c.c
@@ -171,7 +171,7 @@ static void st21nfca_hci_add_len_crc(struct sk_buff *skb)
 	u16 crc;
 	u8 tmp;
 
-	*skb_push(skb, 1) = 0;
+	*(u8 *)skb_push(skb, 1) = 0;
 
 	crc = crc_ccitt(0xffff, skb->data, skb->len);
 	crc = ~crc;
@@ -216,7 +216,7 @@ static int st21nfca_hci_i2c_write(void *phy_id, struct sk_buff *skb)
 	/* add ST21NFCA_SOF_EOF on tail */
 	*(u8 *)skb_put(skb, 1) = ST21NFCA_SOF_EOF;
 	/* add ST21NFCA_SOF_EOF on head */
-	*skb_push(skb, 1) = ST21NFCA_SOF_EOF;
+	*(u8 *)skb_push(skb, 1) = ST21NFCA_SOF_EOF;
 
 	/*
 	 * Compute byte stuffing