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, 2 insertions, 2 deletions

diff --git a/drivers/nfc/port100.c b/drivers/nfc/port100.c
index 5fa3cf0fabd6..bb43cebda9dc 100644
--- a/drivers/nfc/port100.c
+++ b/drivers/nfc/port100.c
@@ -991,7 +991,7 @@ static int port100_set_command_type(struct port100 *dev, u8 command_type)
 	if (!skb)
 		return -ENOMEM;
 
-	*(u8 *)skb_put(skb, sizeof(u8)) = command_type;
+	skb_put_u8(skb, command_type);
 
 	resp = port100_send_cmd_sync(dev, PORT100_CMD_SET_COMMAND_TYPE, skb);
 	if (IS_ERR(resp))
@@ -1059,7 +1059,7 @@ static int port100_switch_rf(struct nfc_digital_dev *ddev, bool on)
 	if (!skb)
 		return -ENOMEM;
 
-	*(u8 *)skb_put(skb, 1) = on ? 1 : 0;
+	skb_put_u8(skb, on ? 1 : 0);
 
 	/* Cancel the last command if the device is being switched off */
 	if (!on)