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, 5 insertions, 5 deletions

diff --git a/net/nfc/nci/data.c b/net/nfc/nci/data.c
index 2488d9241f1d..908f25e3773e 100644
--- a/net/nfc/nci/data.c
+++ b/net/nfc/nci/data.c
@@ -81,7 +81,7 @@ static inline void nci_push_data_hdr(struct nci_dev *ndev,
 	struct nci_data_hdr *hdr;
 	int plen = skb->len;
 
-	hdr = (struct nci_data_hdr *) skb_push(skb, NCI_DATA_HDR_SIZE);
+	hdr = skb_push(skb, NCI_DATA_HDR_SIZE);
 	hdr->conn_id = conn_id;
 	hdr->rfu = 0;
 	hdr->plen = plen;
diff --git a/net/nfc/nci/hci.c b/net/nfc/nci/hci.c
index d1119bb35f24..3f93df58d9f1 100644
--- a/net/nfc/nci/hci.c
+++ b/net/nfc/nci/hci.c
@@ -170,7 +170,7 @@ static int nci_hci_send_data(struct nci_dev *ndev, u8 pipe,
 		return -ENOMEM;
 
 	skb_reserve(skb, NCI_DATA_HDR_SIZE + 2);
-	*skb_push(skb, 1) = data_type;
+	*(u8 *)skb_push(skb, 1) = data_type;
 
 	do {
 		len = conn_info->max_pkt_payload_len;
@@ -184,7 +184,7 @@ static int nci_hci_send_data(struct nci_dev *ndev, u8 pipe,
 			len = conn_info->max_pkt_payload_len - skb->len - 1;
 		}
 
-		*skb_push(skb, 1) = cb;
+		*(u8 *)skb_push(skb, 1) = cb;
 
 		if (len > 0)
 			skb_put_data(skb, data + i, len);
diff --git a/net/nfc/nci/spi.c b/net/nfc/nci/spi.c
index a502a334918a..3b4512731a2f 100644
--- a/net/nfc/nci/spi.c
+++ b/net/nfc/nci/spi.c
@@ -238,8 +238,8 @@ static struct sk_buff *__nci_spi_read(struct nci_spi *nspi)
 		goto receive_error;
 
 	if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
-		*skb_push(skb, 1) = resp_hdr[1];
-		*skb_push(skb, 1) = resp_hdr[0];
+		*(u8 *)skb_push(skb, 1) = resp_hdr[1];
+		*(u8 *)skb_push(skb, 1) = resp_hdr[0];
 	}
 
 	return skb;