[NET] CORE: Introducing new memory accounting interface.

This patch introduces new memory accounting functions for each network
protocol. Most of them are renamed from memory accounting functions
for stream protocols. At the same time, some stream memory accounting
functions are removed since other functions do same thing.

Renaming:
	sk_stream_free_skb()		->	sk_wmem_free_skb()
	__sk_stream_mem_reclaim()	->	__sk_mem_reclaim()
	sk_stream_mem_reclaim()		->	sk_mem_reclaim()
	sk_stream_mem_schedule 		->    	__sk_mem_schedule()
	sk_stream_pages()      		->	sk_mem_pages()
	sk_stream_rmem_schedule()	->	sk_rmem_schedule()
	sk_stream_wmem_schedule()	->	sk_wmem_schedule()
	sk_charge_skb()			->	sk_mem_charge()

Removeing
	sk_stream_rfree():	consolidates into sock_rfree()
	sk_stream_set_owner_r(): consolidates into skb_set_owner_r()
	sk_stream_mem_schedule()

The following functions are added.
    	sk_has_account(): check if the protocol supports accounting
	sk_mem_uncharge(): do the opposite of sk_mem_charge()

In addition, to achieve consolidation, updating sk_wmem_queued is
removed from sk_mem_charge().

Next, to consolidate memory accounting functions, this patch adds
memory accounting calls to network core functions. Moreover, present
memory accounting call is renamed to new accounting call.

Finally we replace present memory accounting calls with new interface
in TCP and SCTP.

Signed-off-by: Takahiro Yasui <tyasui@redhat.com>
Signed-off-by: Hideo Aoki <haoki@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 7a8650f..710df67 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -174,7 +174,8 @@
 				sizeof(struct sctp_chunk);
 
 	atomic_add(sizeof(struct sctp_chunk), &sk->sk_wmem_alloc);
-	sk_charge_skb(sk, chunk->skb);
+	sk->sk_wmem_queued += chunk->skb->truesize;
+	sk_mem_charge(sk, chunk->skb->truesize);
 }
 
 /* Verify that this is a valid address. */
@@ -6035,10 +6036,10 @@
 	atomic_sub(sizeof(struct sctp_chunk), &sk->sk_wmem_alloc);
 
 	/*
-	 * This undoes what is done via sk_charge_skb
+	 * This undoes what is done via sctp_set_owner_w and sk_mem_charge
 	 */
 	sk->sk_wmem_queued   -= skb->truesize;
-	sk->sk_forward_alloc += skb->truesize;
+	sk_mem_uncharge(sk, skb->truesize);
 
 	sock_wfree(skb);
 	__sctp_write_space(asoc);
@@ -6059,9 +6060,9 @@
 	atomic_sub(event->rmem_len, &sk->sk_rmem_alloc);
 
 	/*
-	 * Mimic the behavior of sk_stream_rfree
+	 * Mimic the behavior of sock_rfree
 	 */
-	sk->sk_forward_alloc += event->rmem_len;
+	sk_mem_uncharge(sk, event->rmem_len);
 }