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/pn544/i2c.c b/drivers/nfc/pn544/i2c.c
index b7be6c25b7e6..fedde9d46ab6 100644
--- a/drivers/nfc/pn544/i2c.c
+++ b/drivers/nfc/pn544/i2c.c
@@ -287,8 +287,8 @@ static void pn544_hci_i2c_add_len_crc(struct sk_buff *skb)
 
 	crc = crc_ccitt(0xffff, skb->data, skb->len);
 	crc = ~crc;
-	*(u8 *)skb_put(skb, 1) = crc & 0xff;
-	*(u8 *)skb_put(skb, 1) = crc >> 8;
+	skb_put_u8(skb, crc & 0xff);
+	skb_put_u8(skb, crc >> 8);
 }
 
 static void pn544_hci_i2c_remove_len_crc(struct sk_buff *skb)
@@ -391,7 +391,7 @@ static int pn544_hci_i2c_read(struct pn544_i2c_phy *phy, struct sk_buff **skb)
 		goto flush;
 	}
 
-	*(u8 *)skb_put(*skb, 1) = len;
+	skb_put_u8(*skb, len);
 
 	r = i2c_master_recv(client, skb_put(*skb, len), len);
 	if (r != len) {