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>

3 files changed, 6 insertions, 6 deletions

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 4d4837a0645b..bcb974707118 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -1250,7 +1250,7 @@ cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign)
 		skb_put_zero(skb_out, padding_count);
 	} else if (skb_out->len < ctx->tx_max &&
 		   (skb_out->len % dev->maxpacket) == 0) {
-		*(u8 *)skb_put(skb_out, 1) = 0;	/* force short packet */
+		skb_put_u8(skb_out, 0);	/* force short packet */
 	}
 
 	/* set final frame length */
diff --git a/drivers/net/usb/net1080.c b/drivers/net/usb/net1080.c
index be53ff30b7b5..18a13aa5fcbb 100644
--- a/drivers/net/usb/net1080.c
+++ b/drivers/net/usb/net1080.c
@@ -473,7 +473,7 @@ encapsulate:
 
 	/* maybe pad; then trailer */
 	if (!((skb->len + sizeof *trailer) & 0x01))
-		*(u8 *)skb_put(skb, 1) = PAD_BYTE;
+		skb_put_u8(skb, PAD_BYTE);
 	trailer = skb_put(skb, sizeof *trailer);
 	put_unaligned(header->packet_id, &trailer->packet_id);
 #if 0
diff --git a/drivers/net/usb/zaurus.c b/drivers/net/usb/zaurus.c
index dc3cd03763af..9c2196c3fd11 100644
--- a/drivers/net/usb/zaurus.c
+++ b/drivers/net/usb/zaurus.c
@@ -74,10 +74,10 @@ done:
 		fcs = crc32_le(~0, skb->data, skb->len);
 		fcs = ~fcs;
 
-		*(u8 *)skb_put(skb, 1) = fcs       & 0xff;
-		*(u8 *)skb_put(skb, 1) = (fcs>> 8) & 0xff;
-		*(u8 *)skb_put(skb, 1) = (fcs>>16) & 0xff;
-		*(u8 *)skb_put(skb, 1) = (fcs>>24) & 0xff;
+		skb_put_u8(skb, fcs & 0xff);
+		skb_put_u8(skb, (fcs >> 8) & 0xff);
+		skb_put_u8(skb, (fcs >> 16) & 0xff);
+		skb_put_u8(skb, (fcs >> 24) & 0xff);
 	}
 	return skb;
 }