networking: make skb_put & friends return void pointers

It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.

Make these functions (skb_put, __skb_put and pskb_put) return void *
and remove all the casts across the tree, adding a (u8 *) cast only
where the unsigned char pointer was used directly, all done with the
following spatch:

    @@
    expression SKB, LEN;
    typedef u8;
    identifier fn = { skb_put, __skb_put };
    @@
    - *(fn(SKB, LEN))
    + *(u8 *)fn(SKB, LEN)

    @@
    expression E, SKB, LEN;
    identifier fn = { skb_put, __skb_put };
    type T;
    @@
    - E = ((T *)(fn(SKB, LEN)))
    + E = fn(SKB, LEN)

which actually doesn't cover pskb_put since there are only three
users overall.

A handful of stragglers were converted manually, notably a macro in
drivers/isdn/i4l/isdn_bsdcomp.c and, oddly enough, one of the many
instances in net/bluetooth/hci_sock.c. In the former file, I also
had to fix one whitespace problem spatch introduced.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index fe6a552..303c779 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1048,7 +1048,7 @@ static struct sk_buff *l2cap_create_sframe_pdu(struct l2cap_chan *chan,
 	if (!skb)
 		return ERR_PTR(-ENOMEM);
 
-	lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
+	lh = skb_put(skb, L2CAP_HDR_SIZE);
 	lh->len = cpu_to_le16(hlen - L2CAP_HDR_SIZE);
 	lh->cid = cpu_to_le16(chan->dcid);
 
@@ -2182,7 +2182,7 @@ static struct sk_buff *l2cap_create_connless_pdu(struct l2cap_chan *chan,
 		return skb;
 
 	/* Create L2CAP header */
-	lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
+	lh = skb_put(skb, L2CAP_HDR_SIZE);
 	lh->cid = cpu_to_le16(chan->dcid);
 	lh->len = cpu_to_le16(len + L2CAP_PSMLEN_SIZE);
 	put_unaligned(chan->psm, (__le16 *) skb_put(skb, L2CAP_PSMLEN_SIZE));
@@ -2213,7 +2213,7 @@ static struct sk_buff *l2cap_create_basic_pdu(struct l2cap_chan *chan,
 		return skb;
 
 	/* Create L2CAP header */
-	lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
+	lh = skb_put(skb, L2CAP_HDR_SIZE);
 	lh->cid = cpu_to_le16(chan->dcid);
 	lh->len = cpu_to_le16(len);
 
@@ -2255,7 +2255,7 @@ static struct sk_buff *l2cap_create_iframe_pdu(struct l2cap_chan *chan,
 		return skb;
 
 	/* Create L2CAP header */
-	lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
+	lh = skb_put(skb, L2CAP_HDR_SIZE);
 	lh->cid = cpu_to_le16(chan->dcid);
 	lh->len = cpu_to_le16(len + (hlen - L2CAP_HDR_SIZE));
 
@@ -2373,7 +2373,7 @@ static struct sk_buff *l2cap_create_le_flowctl_pdu(struct l2cap_chan *chan,
 		return skb;
 
 	/* Create L2CAP header */
-	lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
+	lh = skb_put(skb, L2CAP_HDR_SIZE);
 	lh->cid = cpu_to_le16(chan->dcid);
 	lh->len = cpu_to_le16(len + (hlen - L2CAP_HDR_SIZE));
 
@@ -2908,7 +2908,7 @@ static struct sk_buff *l2cap_build_cmd(struct l2cap_conn *conn, u8 code,
 	if (!skb)
 		return NULL;
 
-	lh = (struct l2cap_hdr *) skb_put(skb, L2CAP_HDR_SIZE);
+	lh = skb_put(skb, L2CAP_HDR_SIZE);
 	lh->len = cpu_to_le16(L2CAP_CMD_HDR_SIZE + dlen);
 
 	if (conn->hcon->type == LE_LINK)
@@ -2916,7 +2916,7 @@ static struct sk_buff *l2cap_build_cmd(struct l2cap_conn *conn, u8 code,
 	else
 		lh->cid = cpu_to_le16(L2CAP_CID_SIGNALING);
 
-	cmd = (struct l2cap_cmd_hdr *) skb_put(skb, L2CAP_CMD_HDR_SIZE);
+	cmd = skb_put(skb, L2CAP_CMD_HDR_SIZE);
 	cmd->code  = code;
 	cmd->ident = ident;
 	cmd->len   = cpu_to_le16(dlen);