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/sctp/ulpevent.c b/net/sctp/ulpevent.c
index ec2b3e0..e361f0b 100644
--- a/net/sctp/ulpevent.c
+++ b/net/sctp/ulpevent.c
@@ -167,8 +167,7 @@
 			goto fail;
 
 		skb = sctp_event2skb(event);
-		sac = (struct sctp_assoc_change *) skb_put(skb,
-					sizeof(struct sctp_assoc_change));
+		sac = skb_put(skb, sizeof(struct sctp_assoc_change));
 	}
 
 	/* Socket Extensions for SCTP
@@ -270,8 +269,7 @@
 		goto fail;
 
 	skb = sctp_event2skb(event);
-	spc = (struct sctp_paddr_change *)
-		skb_put(skb, sizeof(struct sctp_paddr_change));
+	spc = skb_put(skb, sizeof(struct sctp_paddr_change));
 
 	/* Sockets API Extensions for SCTP
 	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
@@ -549,8 +547,7 @@
 		goto fail;
 
 	skb = sctp_event2skb(event);
-	sse = (struct sctp_shutdown_event *)
-		skb_put(skb, sizeof(struct sctp_shutdown_event));
+	sse = skb_put(skb, sizeof(struct sctp_shutdown_event));
 
 	/* Socket Extensions for SCTP
 	 * 5.3.1.5 SCTP_SHUTDOWN_EVENT
@@ -612,8 +609,7 @@
 		goto fail;
 
 	skb = sctp_event2skb(event);
-	sai = (struct sctp_adaptation_event *)
-		skb_put(skb, sizeof(struct sctp_adaptation_event));
+	sai = skb_put(skb, sizeof(struct sctp_adaptation_event));
 
 	sai->sai_type = SCTP_ADAPTATION_INDICATION;
 	sai->sai_flags = 0;
@@ -751,8 +747,7 @@
 		goto fail;
 
 	skb = sctp_event2skb(event);
-	pd = (struct sctp_pdapi_event *)
-		skb_put(skb, sizeof(struct sctp_pdapi_event));
+	pd = skb_put(skb, sizeof(struct sctp_pdapi_event));
 
 	/* pdapi_type
 	 *   It should be SCTP_PARTIAL_DELIVERY_EVENT
@@ -803,8 +798,7 @@
 		goto fail;
 
 	skb = sctp_event2skb(event);
-	ak = (struct sctp_authkey_event *)
-		skb_put(skb, sizeof(struct sctp_authkey_event));
+	ak = skb_put(skb, sizeof(struct sctp_authkey_event));
 
 	ak->auth_type = SCTP_AUTHENTICATION_EVENT;
 	ak->auth_flags = 0;
@@ -842,8 +836,7 @@
 		return NULL;
 
 	skb = sctp_event2skb(event);
-	sdry = (struct sctp_sender_dry_event *)
-		skb_put(skb, sizeof(struct sctp_sender_dry_event));
+	sdry = skb_put(skb, sizeof(struct sctp_sender_dry_event));
 
 	sdry->sender_dry_type = SCTP_SENDER_DRY_EVENT;
 	sdry->sender_dry_flags = 0;
@@ -869,7 +862,7 @@
 		return NULL;
 
 	skb = sctp_event2skb(event);
-	sreset = (struct sctp_stream_reset_event *)skb_put(skb, length);
+	sreset = skb_put(skb, length);
 
 	sreset->strreset_type = SCTP_STREAM_RESET_EVENT;
 	sreset->strreset_flags = flags;
@@ -897,8 +890,7 @@
 		return NULL;
 
 	skb = sctp_event2skb(event);
-	areset = (struct sctp_assoc_reset_event *)
-		skb_put(skb, sizeof(struct sctp_assoc_reset_event));
+	areset = skb_put(skb, sizeof(struct sctp_assoc_reset_event));
 
 	areset->assocreset_type = SCTP_ASSOC_RESET_EVENT;
 	areset->assocreset_flags = flags;
@@ -925,8 +917,7 @@
 		return NULL;
 
 	skb = sctp_event2skb(event);
-	schange = (struct sctp_stream_change_event *)
-		skb_put(skb, sizeof(struct sctp_stream_change_event));
+	schange = skb_put(skb, sizeof(struct sctp_stream_change_event));
 
 	schange->strchange_type = SCTP_STREAM_CHANGE_EVENT;
 	schange->strchange_flags = flags;