tipc: use generic SKB list APIs to manage TIPC outgoing packet chains

Use standard SKB list APIs associated with struct sk_buff_head to
manage socket outgoing packet chain and name table outgoing packet
chain, having relevant code simpler and more readable.

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 62 insertions, 36 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 0e04508cdba4..34bf15c90c78 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -664,9 +664,10 @@ static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
  * - For all other messages we discard the buffer and return -EHOSTUNREACH
  * - For TIPC internal messages we also reset the link
  */
-static int tipc_link_cong(struct tipc_link *link, struct sk_buff *buf)
+static int tipc_link_cong(struct tipc_link *link, struct sk_buff_head *list)
 {
-	struct tipc_msg *msg = buf_msg(buf);
+	struct sk_buff *skb = skb_peek(list);
+	struct tipc_msg *msg = buf_msg(skb);
 	uint imp = tipc_msg_tot_importance(msg);
 	u32 oport = msg_tot_origport(msg);
 
@@ -679,28 +680,29 @@ static int tipc_link_cong(struct tipc_link *link, struct sk_buff *buf)
 		goto drop;
 	if (unlikely(msg_reroute_cnt(msg)))
 		goto drop;
-	if (TIPC_SKB_CB(buf)->wakeup_pending)
+	if (TIPC_SKB_CB(skb)->wakeup_pending)
 		return -ELINKCONG;
-	if (link_schedule_user(link, oport, TIPC_SKB_CB(buf)->chain_sz, imp))
+	if (link_schedule_user(link, oport, skb_queue_len(list), imp))
 		return -ELINKCONG;
 drop:
-	kfree_skb_list(buf);
+	__skb_queue_purge(list);
 	return -EHOSTUNREACH;
 }
 
 /**
  * __tipc_link_xmit(): same as tipc_link_xmit, but destlink is known & locked
  * @link: link to use
- * @skb: chain of buffers containing message
+ * @list: chain of buffers containing message
+ *
  * Consumes the buffer chain, except when returning -ELINKCONG
  * Returns 0 if success, otherwise errno: -ELINKCONG, -EMSGSIZE (plain socket
  * user data messages) or -EHOSTUNREACH (all other messages/senders)
  * Only the socket functions tipc_send_stream() and tipc_send_packet() need
  * to act on the return value, since they may need to do more send attempts.
  */
-int __tipc_link_xmit(struct tipc_link *link, struct sk_buff *skb)
+int __tipc_link_xmit(struct tipc_link *link, struct sk_buff_head *list)
 {
-	struct tipc_msg *msg = buf_msg(skb);
+	struct tipc_msg *msg = buf_msg(skb_peek(list));
 	uint psz = msg_size(msg);
 	uint sndlim = link->queue_limit[0];
 	uint imp = tipc_msg_tot_importance(msg);
@@ -710,21 +712,21 @@ int __tipc_link_xmit(struct tipc_link *link, struct sk_buff *skb)
 	uint bc_last_in = link->owner->bclink.last_in;
 	struct tipc_media_addr *addr = &link->media_addr;
 	struct sk_buff_head *outqueue = &link->outqueue;
-	struct sk_buff *next;
+	struct sk_buff *skb, *tmp;
 
 	/* Match queue limits against msg importance: */
 	if (unlikely(skb_queue_len(outqueue) >= link->queue_limit[imp]))
-		return tipc_link_cong(link, skb);
+		return tipc_link_cong(link, list);
 
 	/* Has valid packet limit been used ? */
 	if (unlikely(psz > mtu)) {
-		kfree_skb_list(skb);
+		__skb_queue_purge(list);
 		return -EMSGSIZE;
 	}
 
 	/* Prepare each packet for sending, and add to outqueue: */
-	while (skb) {
-		next = skb->next;
+	skb_queue_walk_safe(list, skb, tmp) {
+		__skb_unlink(skb, list);
 		msg = buf_msg(skb);
 		msg_set_word(msg, 2, ((ack << 16) | mod(seqno)));
 		msg_set_bcast_ack(msg, bc_last_in);
@@ -736,7 +738,6 @@ int __tipc_link_xmit(struct tipc_link *link, struct sk_buff *skb)
 			link->unacked_window = 0;
 		} else if (tipc_msg_bundle(outqueue, skb, mtu)) {
 			link->stats.sent_bundled++;
-			skb = next;
 			continue;
 		} else if (tipc_msg_make_bundle(outqueue, skb, mtu,
 						link->addr)) {
@@ -750,22 +751,43 @@ int __tipc_link_xmit(struct tipc_link *link, struct sk_buff *skb)
 				link->next_out = skb;
 		}
 		seqno++;
-		skb = next;
 	}
 	link->next_out_no = seqno;
 	return 0;
 }
 
+static void skb2list(struct sk_buff *skb, struct sk_buff_head *list)
+{
+	__skb_queue_head_init(list);
+	__skb_queue_tail(list, skb);
+}
+
+static int __tipc_link_xmit_skb(struct tipc_link *link, struct sk_buff *skb)
+{
+	struct sk_buff_head head;
+
+	skb2list(skb, &head);
+	return __tipc_link_xmit(link, &head);
+}
+
+int tipc_link_xmit_skb(struct sk_buff *skb, u32 dnode, u32 selector)
+{
+	struct sk_buff_head head;
+
+	skb2list(skb, &head);
+	return tipc_link_xmit(&head, dnode, selector);
+}
+
 /**
  * tipc_link_xmit() is the general link level function for message sending
- * @buf: chain of buffers containing message
+ * @list: chain of buffers containing message
  * @dsz: amount of user data to be sent
  * @dnode: address of destination node
  * @selector: a number used for deterministic link selection
  * Consumes the buffer chain, except when returning -ELINKCONG
  * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
  */
-int tipc_link_xmit(struct sk_buff *buf, u32 dnode, u32 selector)
+int tipc_link_xmit(struct sk_buff_head *list, u32 dnode, u32 selector)
 {
 	struct tipc_link *link = NULL;
 	struct tipc_node *node;
@@ -776,17 +798,22 @@ int tipc_link_xmit(struct sk_buff *buf, u32 dnode, u32 selector)
 		tipc_node_lock(node);
 		link = node->active_links[selector & 1];
 		if (link)
-			rc = __tipc_link_xmit(link, buf);
+			rc = __tipc_link_xmit(link, list);
 		tipc_node_unlock(node);
 	}
 
 	if (link)
 		return rc;
 
-	if (likely(in_own_node(dnode)))
-		return tipc_sk_rcv(buf);
+	if (likely(in_own_node(dnode))) {
+		/* As a node local message chain never contains more than one
+		 * buffer, we just need to dequeue one SKB buffer from the
+		 * head list.
+		 */
+		return tipc_sk_rcv(__skb_dequeue(list));
+	}
+	__skb_queue_purge(list);
 
-	kfree_skb_list(buf);
 	return rc;
 }
 
@@ -800,17 +827,17 @@ int tipc_link_xmit(struct sk_buff *buf, u32 dnode, u32 selector)
  */
 static void tipc_link_sync_xmit(struct tipc_link *link)
 {
-	struct sk_buff *buf;
+	struct sk_buff *skb;
 	struct tipc_msg *msg;
 
-	buf = tipc_buf_acquire(INT_H_SIZE);
-	if (!buf)
+	skb = tipc_buf_acquire(INT_H_SIZE);
+	if (!skb)
 		return;
 
-	msg = buf_msg(buf);
+	msg = buf_msg(skb);
 	tipc_msg_init(msg, BCAST_PROTOCOL, STATE_MSG, INT_H_SIZE, link->addr);
 	msg_set_last_bcast(msg, link->owner->bclink.acked);
-	__tipc_link_xmit(link, buf);
+	__tipc_link_xmit_skb(link, skb);
 }
 
 /*
@@ -1053,8 +1080,7 @@ void tipc_rcv(struct sk_buff *skb, struct tipc_bearer *b_ptr)
 	u32 ackd;
 	u32 released;
 
-	__skb_queue_head_init(&head);
-	__skb_queue_tail(&head, skb);
+	skb2list(skb, &head);
 
 	while ((skb = __skb_dequeue(&head))) {
 		/* Ensure message is well-formed */
@@ -1573,7 +1599,7 @@ static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
 				  u32 selector)
 {
 	struct tipc_link *tunnel;
-	struct sk_buff *buf;
+	struct sk_buff *skb;
 	u32 length = msg_size(msg);
 
 	tunnel = l_ptr->owner->active_links[selector & 1];
@@ -1582,14 +1608,14 @@ static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
 		return;
 	}
 	msg_set_size(tunnel_hdr, length + INT_H_SIZE);
-	buf = tipc_buf_acquire(length + INT_H_SIZE);
-	if (!buf) {
+	skb = tipc_buf_acquire(length + INT_H_SIZE);
+	if (!skb) {
 		pr_warn("%sunable to send tunnel msg\n", link_co_err);
 		return;
 	}
-	skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
-	skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
-	__tipc_link_xmit(tunnel, buf);
+	skb_copy_to_linear_data(skb, tunnel_hdr, INT_H_SIZE);
+	skb_copy_to_linear_data_offset(skb, INT_H_SIZE, msg, length);
+	__tipc_link_xmit_skb(tunnel, skb);
 }
 
 
@@ -1620,7 +1646,7 @@ void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
 		if (skb) {
 			skb_copy_to_linear_data(skb, &tunnel_hdr, INT_H_SIZE);
 			msg_set_size(&tunnel_hdr, INT_H_SIZE);
-			__tipc_link_xmit(tunnel, skb);
+			__tipc_link_xmit_skb(tunnel, skb);
 		} else {
 			pr_warn("%sunable to send changeover msg\n",
 				link_co_err);
@@ -1691,7 +1717,7 @@ void tipc_link_dup_queue_xmit(struct tipc_link *l_ptr,
 		skb_copy_to_linear_data(outskb, &tunnel_hdr, INT_H_SIZE);
 		skb_copy_to_linear_data_offset(outskb, INT_H_SIZE, skb->data,
 					       length);
-		__tipc_link_xmit(tunnel, outskb);
+		__tipc_link_xmit_skb(tunnel, outskb);
 		if (!tipc_link_is_up(l_ptr))
 			return;
 	}