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/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index ba207c7..fa24d69 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -1844,7 +1844,7 @@ static int inject_cmd_complete(struct hci_dev *hdev, __u16 opcode)
 	evt->ncmd = 0x01;
 	evt->opcode = cpu_to_le16(opcode);
 
-	*(u8 *)skb_put(skb, 1) = 0x00;
+	skb_put_u8(skb, 0x00);
 
 	hci_skb_pkt_type(skb) = HCI_EVENT_PKT;
 
@@ -2767,8 +2767,8 @@ static struct urb *alloc_diag_urb(struct hci_dev *hdev, bool enable)
 		return ERR_PTR(-ENOMEM);
 	}
 
-	*(u8 *)skb_put(skb, 1) = 0xf0;
-	*(u8 *)skb_put(skb, 1) = enable;
+	skb_put_u8(skb, 0xf0);
+	skb_put_u8(skb, enable);
 
 	pipe = usb_sndbulkpipe(data->udev, data->diag_tx_ep->bEndpointAddress);