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>

4 files changed, 19 insertions, 18 deletions

diff --git a/drivers/isdn/capi/capi.c b/drivers/isdn/capi/capi.c
index 96f586d34d2d..dde8f46bc254 100644
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -1082,7 +1082,7 @@ static int capinc_tty_put_char(struct tty_struct *tty, unsigned char ch)
 	skb = mp->outskb;
 	if (skb) {
 		if (skb_tailroom(skb) > 0) {
-			*(u8 *)skb_put(skb, 1) = ch;
+			skb_put_u8(skb, ch);
 			goto unlock_out;
 		}
 		mp->outskb = NULL;
@@ -1094,7 +1094,7 @@ static int capinc_tty_put_char(struct tty_struct *tty, unsigned char ch)
 	skb = alloc_skb(CAPI_DATA_B3_REQ_LEN + CAPI_MAX_BLKSIZE, GFP_ATOMIC);
 	if (skb) {
 		skb_reserve(skb, CAPI_DATA_B3_REQ_LEN);
-		*(u8 *)skb_put(skb, 1) = ch;
+		skb_put_u8(skb, ch);
 		mp->outskb = skb;
 	} else {
 		printk(KERN_ERR "capinc_put_char: char %u lost\n", ch);
diff --git a/drivers/isdn/gigaset/asyncdata.c b/drivers/isdn/gigaset/asyncdata.c
index 03ac9fbfe318..4caecdcc6f29 100644
--- a/drivers/isdn/gigaset/asyncdata.c
+++ b/drivers/isdn/gigaset/asyncdata.c
@@ -492,33 +492,33 @@ static struct sk_buff *HDLC_Encode(struct sk_buff *skb)
 	hdlc_skb->mac_len = skb->mac_len;
 
 	/* Add flag sequence in front of everything.. */
-	*(u8 *)skb_put(hdlc_skb, 1) = PPP_FLAG;
+	skb_put_u8(hdlc_skb, PPP_FLAG);
 
 	/* Perform byte stuffing while copying data. */
 	while (skb->len--) {
 		if (muststuff(*skb->data)) {
-			*(u8 *)skb_put(hdlc_skb, 1) = PPP_ESCAPE;
-			*(u8 *)skb_put(hdlc_skb, 1) = (*skb->data++) ^ PPP_TRANS;
+			skb_put_u8(hdlc_skb, PPP_ESCAPE);
+			skb_put_u8(hdlc_skb, (*skb->data++) ^ PPP_TRANS);
 		} else
-			*(u8 *)skb_put(hdlc_skb, 1) = *skb->data++;
+			skb_put_u8(hdlc_skb, *skb->data++);
 	}
 
 	/* Finally add FCS (byte stuffed) and flag sequence */
 	c = (fcs & 0x00ff);	/* least significant byte first */
 	if (muststuff(c)) {
-		*(u8 *)skb_put(hdlc_skb, 1) = PPP_ESCAPE;
+		skb_put_u8(hdlc_skb, PPP_ESCAPE);
 		c ^= PPP_TRANS;
 	}
-	*(u8 *)skb_put(hdlc_skb, 1) = c;
+	skb_put_u8(hdlc_skb, c);
 
 	c = ((fcs >> 8) & 0x00ff);
 	if (muststuff(c)) {
-		*(u8 *)skb_put(hdlc_skb, 1) = PPP_ESCAPE;
+		skb_put_u8(hdlc_skb, PPP_ESCAPE);
 		c ^= PPP_TRANS;
 	}
-	*(u8 *)skb_put(hdlc_skb, 1) = c;
+	skb_put_u8(hdlc_skb, c);
 
-	*(u8 *)skb_put(hdlc_skb, 1) = PPP_FLAG;
+	skb_put_u8(hdlc_skb, PPP_FLAG);
 
 	dev_kfree_skb_any(skb);
 	return hdlc_skb;
@@ -561,8 +561,8 @@ static struct sk_buff *iraw_encode(struct sk_buff *skb)
 	while (len--) {
 		c = bitrev8(*cp++);
 		if (c == DLE_FLAG)
-			*(u8 *)skb_put(iraw_skb, 1) = c;
-		*(u8 *)skb_put(iraw_skb, 1) = c;
+			skb_put_u8(iraw_skb, c);
+		skb_put_u8(iraw_skb, c);
 	}
 	dev_kfree_skb_any(skb);
 	return iraw_skb;
diff --git a/drivers/isdn/i4l/isdn_bsdcomp.c b/drivers/isdn/i4l/isdn_bsdcomp.c
index 6ade0916da4e..3035210a6119 100644
--- a/drivers/isdn/i4l/isdn_bsdcomp.c
+++ b/drivers/isdn/i4l/isdn_bsdcomp.c
@@ -602,7 +602,8 @@ static int bsd_compress(void *state, struct sk_buff *skb_in, struct sk_buff *skb
 	 * Do not emit a completely useless byte of ones.
 	 */
 	if (bitno < 32 && skb_out && skb_tailroom(skb_out) > 0)
-		*(u8 *)skb_put(skb_out, 1) = (unsigned char)((accm | (0xff << (bitno - 8))) >> 24);
+		skb_put_u8(skb_out,
+			   (unsigned char)((accm | (0xff << (bitno - 8))) >> 24));
 
 	/*
 	 * Increase code size if we would have without the packet
@@ -698,7 +699,7 @@ static int bsd_decompress(void *state, struct sk_buff *skb_in, struct sk_buff *s
 	db->bytes_out += ilen;
 
 	if (skb_tailroom(skb_out) > 0)
-		*(u8 *)skb_put(skb_out, 1) = 0;
+		skb_put_u8(skb_out, 0);
 	else
 		return DECOMP_ERR_NOMEM;
 
@@ -816,7 +817,7 @@ static int bsd_decompress(void *state, struct sk_buff *skb_in, struct sk_buff *s
 #endif
 
 		if (extra)		/* the KwKwK case again */
-			*(u8 *)skb_put(skb_out, 1) = finchar;
+			skb_put_u8(skb_out, finchar);
 
 		/*
 		 * If not first code in a packet, and
diff --git a/drivers/isdn/i4l/isdn_x25iface.c b/drivers/isdn/i4l/isdn_x25iface.c
index e33fa3073f74..48bfbcb4a09d 100644
--- a/drivers/isdn/i4l/isdn_x25iface.c
+++ b/drivers/isdn/i4l/isdn_x25iface.c
@@ -224,7 +224,7 @@ static int isdn_x25iface_connect_ind(struct concap_proto *cprot)
 
 	skb = dev_alloc_skb(1);
 	if (skb) {
-		*(u8 *)skb_put(skb, 1) = X25_IFACE_CONNECT;
+		skb_put_u8(skb, X25_IFACE_CONNECT);
 		skb->protocol = x25_type_trans(skb, cprot->net_dev);
 		netif_rx(skb);
 		return 0;
@@ -253,7 +253,7 @@ static int isdn_x25iface_disconn_ind(struct concap_proto *cprot)
 	*state_p = WAN_DISCONNECTED;
 	skb = dev_alloc_skb(1);
 	if (skb) {
-		*(u8 *)skb_put(skb, 1) = X25_IFACE_DISCONNECT;
+		skb_put_u8(skb, X25_IFACE_DISCONNECT);
 		skb->protocol = x25_type_trans(skb, cprot->net_dev);
 		netif_rx(skb);
 		return 0;