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, 3 insertions, 3 deletions

diff --git a/drivers/nfc/st21nfca/i2c.c b/drivers/nfc/st21nfca/i2c.c
index 396cdafb3e36..4bff76baa341 100644
--- a/drivers/nfc/st21nfca/i2c.c
+++ b/drivers/nfc/st21nfca/i2c.c
@@ -177,10 +177,10 @@ static void st21nfca_hci_add_len_crc(struct sk_buff *skb)
 	crc = ~crc;
 
 	tmp = crc & 0x00ff;
-	*(u8 *)skb_put(skb, 1) = tmp;
+	skb_put_u8(skb, tmp);
 
 	tmp = (crc >> 8) & 0x00ff;
-	*(u8 *)skb_put(skb, 1) = tmp;
+	skb_put_u8(skb, tmp);
 }
 
 static void st21nfca_hci_remove_len_crc(struct sk_buff *skb)
@@ -214,7 +214,7 @@ static int st21nfca_hci_i2c_write(void *phy_id, struct sk_buff *skb)
 	st21nfca_hci_add_len_crc(skb);
 
 	/* add ST21NFCA_SOF_EOF on tail */
-	*(u8 *)skb_put(skb, 1) = ST21NFCA_SOF_EOF;
+	skb_put_u8(skb, ST21NFCA_SOF_EOF);
 	/* add ST21NFCA_SOF_EOF on head */
 	*(u8 *)skb_push(skb, 1) = ST21NFCA_SOF_EOF;