networking: add and use skb_put_u8()

Joe and Bjørn suggested that it'd be nicer to not have the
cast in the fairly common case of doing
	*(u8 *)skb_put(skb, 1) = c;

Add skb_put_u8() for this case, and use it across the code,
using the following spatch:

    @@
    expression SKB, C, S;
    typedef u8;
    identifier fn = {skb_put};
    fresh identifier fn2 = fn ## "_u8";
    @@
    - *(u8 *)fn(SKB, S) = C;
    + fn2(SKB, C);

Note that due to the "S", the spatch isn't perfect, it should
have checked that S is 1, but there's also places that use a
sizeof expression like sizeof(var) or sizeof(u8) etc. Turns
out that nobody ever did something like
	*(u8 *)skb_put(skb, 2) = c;

which would be wrong anyway since the second byte wouldn't be
initialized.

Suggested-by: Joe Perches <joe@perches.com>
Suggested-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 4 deletions

diff --git a/net/nfc/nci/spi.c b/net/nfc/nci/spi.c
index 3b4512731a2f..452f4c16b7a9 100644
--- a/net/nfc/nci/spi.c
+++ b/net/nfc/nci/spi.c
@@ -86,8 +86,8 @@ int nci_spi_send(struct nci_spi *nspi,
 		u16 crc;
 
 		crc = crc_ccitt(CRC_INIT, skb->data, skb->len);
-		*(u8 *)skb_put(skb, 1) = crc >> 8;
-		*(u8 *)skb_put(skb, 1) = crc & 0xFF;
+		skb_put_u8(skb, crc >> 8);
+		skb_put_u8(skb, crc & 0xFF);
 	}
 
 	if (write_handshake_completion)	{
@@ -172,8 +172,8 @@ static int send_acknowledge(struct nci_spi *nspi, u8 acknowledge)
 	hdr[3] = 0;
 
 	crc = crc_ccitt(CRC_INIT, skb->data, skb->len);
-	*(u8 *)skb_put(skb, 1) = crc >> 8;
-	*(u8 *)skb_put(skb, 1) = crc & 0xFF;
+	skb_put_u8(skb, crc >> 8);
+	skb_put_u8(skb, crc & 0xFF);
 
 	ret = __nci_spi_send(nspi, skb, 0);