[NET] Generalise tcp_{writequeue_purge,rmem_schedule,alloc_{pskb,page}}

Only new requirement was to add a max_header field to struct sock sk_prot
member.
Signed-off-by: Arnaldo Carvalho de Melo <acme@conectiva.com.br>

include/net/sock.h

@@ -553,6 +553,7 @@ struct proto {
 	int			sysctl_mem[3];
 	int			sysctl_wmem[3];
 	int			sysctl_rmem[3];
+	int			max_header;
 
 	char			name[32];
 
@@ -660,6 +661,21 @@ static inline void sk_stream_mem_reclaim(struct sock *sk)
 		__sk_stream_mem_reclaim(sk);
 }
 
+static inline void sk_stream_writequeue_purge(struct sock *sk)
+{
+	struct sk_buff *skb;
+
+	while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
+		sk_stream_free_skb(sk, skb);
+	sk_stream_mem_reclaim(sk);
+}
+
+static inline int sk_stream_rmem_schedule(struct sock *sk, struct sk_buff *skb)
+{
+	return (int)skb->truesize <= sk->sk_forward_alloc ||
+		sk_stream_mem_schedule(sk, skb->truesize, 1);
+}
+
 /* Used by processes to "lock" a socket state, so that
  * interrupts and bottom half handlers won't change it
  * from under us. It essentially blocks any incoming
@@ -1141,6 +1157,46 @@ static inline void sk_stream_moderate_sndbuf(struct sock *sk)
 	}
 }
 
+static inline struct sk_buff *sk_stream_alloc_pskb(struct sock *sk,
+						   int size, int mem, int gfp)
+{
+	struct sk_buff *skb = alloc_skb(size + sk->sk_prot->max_header, gfp);
+
+	if (skb) {
+		skb->truesize += mem;
+		if (sk->sk_forward_alloc >= (int)skb->truesize ||
+		    sk_stream_mem_schedule(sk, skb->truesize, 0)) {
+			skb_reserve(skb, sk->sk_prot->max_header);
+			return skb;
+		}
+		__kfree_skb(skb);
+	} else {
+		sk->sk_prot->enter_memory_pressure();
+		sk_stream_moderate_sndbuf(sk);
+	}
+	return NULL;
+}
+
+static inline struct sk_buff *sk_stream_alloc_skb(struct sock *sk,
+						  int size, int gfp)
+{
+	return sk_stream_alloc_pskb(sk, size, 0, gfp);
+}
+
+static inline struct page *sk_stream_alloc_page(struct sock *sk)
+{
+	struct page *page = NULL;
+
+	if (sk->sk_forward_alloc >= (int)PAGE_SIZE ||
+	    sk_stream_mem_schedule(sk, PAGE_SIZE, 0))
+		page = alloc_pages(sk->sk_allocation, 0);
+	else {
+		sk->sk_prot->enter_memory_pressure();
+		sk_stream_moderate_sndbuf(sk);
+	}
+	return page;
+}
+
 #define sk_stream_for_retrans_queue(skb, sk)				\
 		for (skb = (sk)->sk_write_queue.next;			\
 		     (skb != (sk)->sk_send_head) &&			\

include/net/tcp.h

@@ -1862,52 +1862,6 @@ static __inline__ void tcp_openreq_init(struct open_request *req,
 
 extern void tcp_enter_memory_pressure(void);
 
-static inline struct sk_buff *tcp_alloc_pskb(struct sock *sk, int size, int mem, int gfp)
-{
-	struct sk_buff *skb = alloc_skb(size+MAX_TCP_HEADER, gfp);
-
-	if (skb) {
-		skb->truesize += mem;
-		if (sk->sk_forward_alloc >= (int)skb->truesize ||
-		    sk_stream_mem_schedule(sk, skb->truesize, 0)) {
-			skb_reserve(skb, MAX_TCP_HEADER);
-			return skb;
-		}
-		__kfree_skb(skb);
-	} else {
-		tcp_enter_memory_pressure();
-		sk_stream_moderate_sndbuf(sk);
-	}
-	return NULL;
-}
-
-static inline struct sk_buff *tcp_alloc_skb(struct sock *sk, int size, int gfp)
-{
-	return tcp_alloc_pskb(sk, size, 0, gfp);
-}
-
-static inline struct page * tcp_alloc_page(struct sock *sk)
-{
-	if (sk->sk_forward_alloc >= (int)PAGE_SIZE ||
-	    sk_stream_mem_schedule(sk, PAGE_SIZE, 0)) {
-		struct page *page = alloc_pages(sk->sk_allocation, 0);
-		if (page)
-			return page;
-	}
-	tcp_enter_memory_pressure();
-	sk_stream_moderate_sndbuf(sk);
-	return NULL;
-}
-
-static inline void tcp_writequeue_purge(struct sock *sk)
-{
-	struct sk_buff *skb;
-
-	while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
-		sk_stream_free_skb(sk, skb);
-	sk_stream_mem_reclaim(sk);
-}
-
 extern void tcp_listen_wlock(void);
 
 /* - We may sleep inside this lock.

net/ipv4/tcp.c

@@ -639,7 +639,7 @@ static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffse
 			if (!sk_stream_memory_free(sk))
 				goto wait_for_sndbuf;
 
-			skb = tcp_alloc_pskb(sk, 0, tp->mss_cache,
+			skb = sk_stream_alloc_pskb(sk, 0, tp->mss_cache,
 						   sk->sk_allocation);
 			if (!skb)
 				goto wait_for_memory;
@@ -806,7 +806,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 				if (!sk_stream_memory_free(sk))
 					goto wait_for_sndbuf;
 
-				skb = tcp_alloc_pskb(sk, select_size(sk, tp),
+				skb = sk_stream_alloc_pskb(sk, select_size(sk, tp),
 							   0, sk->sk_allocation);
 				if (!skb)
 					goto wait_for_memory;
@@ -868,7 +868,7 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 
 				if (!page) {
 					/* Allocate new cache page. */
-					if (!(page = tcp_alloc_page(sk)))
+					if (!(page = sk_stream_alloc_page(sk)))
 						goto wait_for_memory;
 					off = 0;
 				}
@@ -1778,7 +1778,7 @@ int tcp_disconnect(struct sock *sk, int flags)
 
 	tcp_clear_xmit_timers(sk);
 	__skb_queue_purge(&sk->sk_receive_queue);
-	tcp_writequeue_purge(sk);
+	sk_stream_writequeue_purge(sk);
 	__skb_queue_purge(&tp->out_of_order_queue);
 
 	inet->dport = 0;

net/ipv4/tcp_input.c

@@ -3390,12 +3390,6 @@ static void tcp_ofo_queue(struct sock *sk)
 	}
 }
 
-static inline int tcp_rmem_schedule(struct sock *sk, struct sk_buff *skb)
-{
-	return (int)skb->truesize <= sk->sk_forward_alloc ||
-		sk_stream_mem_schedule(sk, skb->truesize, 1);
-}
-
 static int tcp_prune_queue(struct sock *sk);
 
 static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
@@ -3449,8 +3443,9 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
 queue_and_out:
 			if (eaten < 0 &&
 			    (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
-			     !tcp_rmem_schedule(sk, skb))) {
-				if (tcp_prune_queue(sk) < 0 || !tcp_rmem_schedule(sk, skb))
+			     !sk_stream_rmem_schedule(sk, skb))) {
+				if (tcp_prune_queue(sk) < 0 ||
+				    !sk_stream_rmem_schedule(sk, skb))
 					goto drop;
 			}
 			sk_stream_set_owner_r(skb, sk);
@@ -3522,8 +3517,9 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
 	TCP_ECN_check_ce(tp, skb);
 
 	if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
-	    !tcp_rmem_schedule(sk, skb)) {
-		if (tcp_prune_queue(sk) < 0 || !tcp_rmem_schedule(sk, skb))
+	    !sk_stream_rmem_schedule(sk, skb)) {
+		if (tcp_prune_queue(sk) < 0 ||
+		    !sk_stream_rmem_schedule(sk, skb))
 			goto drop;
 	}
 

net/ipv4/tcp_ipv4.c

@@ -2101,7 +2101,7 @@ static int tcp_v4_destroy_sock(struct sock *sk)
 	tcp_clear_xmit_timers(sk);
 
 	/* Cleanup up the write buffer. */
-  	tcp_writequeue_purge(sk);
+  	sk_stream_writequeue_purge(sk);
 
 	/* Cleans up our, hopefully empty, out_of_order_queue. */
   	__skb_queue_purge(&tp->out_of_order_queue);
@@ -2602,6 +2602,7 @@ struct proto tcp_prot = {
 	.enter_memory_pressure	= tcp_enter_memory_pressure,
 	.sysctl_wmem		= { 4 * 1024, 16 * 1024, 128 * 1024 },
 	.sysctl_rmem		= { 4 * 1024, 87380, 87380 * 2 },
+	.max_header		= MAX_TCP_HEADER,
 };
 
 

net/ipv4/tcp_output.c

@@ -372,7 +372,7 @@ static int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len)
 		return -ENOMEM;
 
 	/* Get a new skb... force flag on. */
-	buff = tcp_alloc_skb(sk, nsize, GFP_ATOMIC);
+	buff = sk_stream_alloc_skb(sk, nsize, GFP_ATOMIC);
 	if (buff == NULL)
 		return -ENOMEM; /* We'll just try again later. */
 	sk_charge_skb(sk, buff);

net/ipv6/tcp_ipv6.c

@@ -1898,7 +1898,7 @@ static int tcp_v6_destroy_sock(struct sock *sk)
 	tcp_clear_xmit_timers(sk);
 
 	/* Cleanup up the write buffer. */
-  	tcp_writequeue_purge(sk);
+  	sk_stream_writequeue_purge(sk);
 
 	/* Cleans up our, hopefully empty, out_of_order_queue. */
   	__skb_queue_purge(&tp->out_of_order_queue);
@@ -2096,6 +2096,7 @@ struct proto tcpv6_prot = {
 	.hash		=	tcp_v6_hash,
 	.unhash		=	tcp_unhash,
 	.get_port	=	tcp_v6_get_port,
+	.max_header	=	MAX_TCP_HEADER,
 };
 
 static struct inet6_protocol tcpv6_protocol = {