[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/ipv4/tcp.c b/net/ipv4/tcp.c
index fdaf965..2cbfa6d 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -308,7 +308,7 @@
 /*
  * Pressure flag: try to collapse.
  * Technical note: it is used by multiple contexts non atomically.
- * All the sk_stream_mem_schedule() is of this nature: accounting
+ * All the __sk_mem_schedule() is of this nature: accounting
  * is strict, actions are advisory and have some latency.
  */
 int tcp_memory_pressure __read_mostly;
@@ -485,7 +485,8 @@
 	tcb->sacked  = 0;
 	skb_header_release(skb);
 	tcp_add_write_queue_tail(sk, skb);
-	sk_charge_skb(sk, skb);
+	sk->sk_wmem_queued += skb->truesize;
+	sk_mem_charge(sk, skb->truesize);
 	if (tp->nonagle & TCP_NAGLE_PUSH)
 		tp->nonagle &= ~TCP_NAGLE_PUSH;
 }
@@ -638,7 +639,7 @@
 
 	skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
 	if (skb) {
-		if (sk_stream_wmem_schedule(sk, skb->truesize)) {
+		if (sk_wmem_schedule(sk, skb->truesize)) {
 			/*
 			 * Make sure that we have exactly size bytes
 			 * available to the caller, no more, no less.
@@ -707,7 +708,7 @@
 			tcp_mark_push(tp, skb);
 			goto new_segment;
 		}
-		if (!sk_stream_wmem_schedule(sk, copy))
+		if (!sk_wmem_schedule(sk, copy))
 			goto wait_for_memory;
 
 		if (can_coalesce) {
@@ -721,7 +722,7 @@
 		skb->data_len += copy;
 		skb->truesize += copy;
 		sk->sk_wmem_queued += copy;
-		sk->sk_forward_alloc -= copy;
+		sk_mem_charge(sk, copy);
 		skb->ip_summed = CHECKSUM_PARTIAL;
 		tp->write_seq += copy;
 		TCP_SKB_CB(skb)->end_seq += copy;
@@ -928,7 +929,7 @@
 				if (copy > PAGE_SIZE - off)
 					copy = PAGE_SIZE - off;
 
-				if (!sk_stream_wmem_schedule(sk, copy))
+				if (!sk_wmem_schedule(sk, copy))
 					goto wait_for_memory;
 
 				if (!page) {
@@ -1019,7 +1020,7 @@
 		 * reset, where we can be unlinking the send_head.
 		 */
 		tcp_check_send_head(sk, skb);
-		sk_stream_free_skb(sk, skb);
+		sk_wmem_free_skb(sk, skb);
 	}
 
 do_error:
@@ -1738,7 +1739,7 @@
 		__kfree_skb(skb);
 	}
 
-	sk_stream_mem_reclaim(sk);
+	sk_mem_reclaim(sk);
 
 	/* As outlined in RFC 2525, section 2.17, we send a RST here because
 	 * data was lost. To witness the awful effects of the old behavior of
@@ -1841,7 +1842,7 @@
 		}
 	}
 	if (sk->sk_state != TCP_CLOSE) {
-		sk_stream_mem_reclaim(sk);
+		sk_mem_reclaim(sk);
 		if (tcp_too_many_orphans(sk,
 				atomic_read(sk->sk_prot->orphan_count))) {
 			if (net_ratelimit())
@@ -2658,11 +2659,11 @@
 	limit = ((unsigned long)sysctl_tcp_mem[1]) << (PAGE_SHIFT - 7);
 	max_share = min(4UL*1024*1024, limit);
 
-	sysctl_tcp_wmem[0] = SK_STREAM_MEM_QUANTUM;
+	sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
 	sysctl_tcp_wmem[1] = 16*1024;
 	sysctl_tcp_wmem[2] = max(64*1024, max_share);
 
-	sysctl_tcp_rmem[0] = SK_STREAM_MEM_QUANTUM;
+	sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
 	sysctl_tcp_rmem[1] = 87380;
 	sysctl_tcp_rmem[2] = max(87380, max_share);