tipc: use generic SKB list APIs to manage deferred queue of link

Use standard SKB list APIs associated with struct sk_buff_head to
manage link's deferred queue, simplifying relevant code.

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>

5 files changed, 47 insertions, 69 deletions

diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 4a1a3c8627d0..7b238b1f339b 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -352,6 +352,8 @@ void tipc_bclink_update_link_state(struct tipc_node *n_ptr, u32 last_sent)
         buf = tipc_buf_acquire(INT_H_SIZE);
         if (buf) {
                 struct tipc_msg *msg = buf_msg(buf);
+                struct sk_buff *skb = skb_peek(&n_ptr->bclink.deferred_queue);
+                u32 to = skb ? buf_seqno(skb) - 1 : n_ptr->bclink.last_sent;
 
                 tipc_msg_init(msg, BCAST_PROTOCOL, STATE_MSG,
                               INT_H_SIZE, n_ptr->addr);
@@ -359,9 +361,7 @@ void tipc_bclink_update_link_state(struct tipc_node *n_ptr, u32 last_sent)
                 msg_set_mc_netid(msg, tipc_net_id);
                 msg_set_bcast_ack(msg, n_ptr->bclink.last_in);
                 msg_set_bcgap_after(msg, n_ptr->bclink.last_in);
-                msg_set_bcgap_to(msg, n_ptr->bclink.deferred_head
-                                 ? buf_seqno(n_ptr->bclink.deferred_head) - 1
-                                 : n_ptr->bclink.last_sent);
+                msg_set_bcgap_to(msg, to);
 
                 tipc_bclink_lock();
                 tipc_bearer_send(MAX_BEARERS, buf, NULL);
@@ -574,31 +574,26 @@ receive:
                 if (node->bclink.last_in == node->bclink.last_sent)
                         goto unlock;
 
-                if (!node->bclink.deferred_head) {
+                if (skb_queue_empty(&node->bclink.deferred_queue)) {
                         node->bclink.oos_state = 1;
                         goto unlock;
                 }
 
-                msg = buf_msg(node->bclink.deferred_head);
+                msg = buf_msg(skb_peek(&node->bclink.deferred_queue));
                 seqno = msg_seqno(msg);
                 next_in = mod(next_in + 1);
                 if (seqno != next_in)
                         goto unlock;
 
                 /* Take in-sequence message from deferred queue & deliver it */
-                buf = node->bclink.deferred_head;
-                node->bclink.deferred_head = buf->next;
-                buf->next = NULL;
-                node->bclink.deferred_size--;
+                buf = __skb_dequeue(&node->bclink.deferred_queue);
                 goto receive;
         }
 
         /* Handle out-of-sequence broadcast message */
         if (less(next_in, seqno)) {
-                deferred = tipc_link_defer_pkt(&node->bclink.deferred_head,
-                                               &node->bclink.deferred_tail,
+                deferred = tipc_link_defer_pkt(&node->bclink.deferred_queue,
                                                buf);
-                node->bclink.deferred_size += deferred;
                 bclink_update_last_sent(node, seqno);
                 buf = NULL;
         }
@@ -954,6 +949,7 @@ int tipc_bclink_init(void)
 
         spin_lock_init(&bclink->lock);
         __skb_queue_head_init(&bcl->outqueue);
+        __skb_queue_head_init(&bcl->deferred_queue);
         __skb_queue_head_init(&bcl->waiting_sks);
         bcl->next_out_no = 1;
         spin_lock_init(&bclink->node.lock);
diff --git a/net/tipc/link.c b/net/tipc/link.c
index 9e94bf935e48..d9c2310e417d 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -292,6 +292,7 @@ struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 
         l_ptr->next_out_no = 1;
         __skb_queue_head_init(&l_ptr->outqueue);
+        __skb_queue_head_init(&l_ptr->deferred_queue);
         __skb_queue_head_init(&l_ptr->waiting_sks);
 
         link_reset_statistics(l_ptr);
@@ -398,7 +399,7 @@ void tipc_link_reset_fragments(struct tipc_link *l_ptr)
  */
 void tipc_link_purge_queues(struct tipc_link *l_ptr)
 {
-        kfree_skb_list(l_ptr->oldest_deferred_in);
+        __skb_queue_purge(&l_ptr->deferred_queue);
         __skb_queue_purge(&l_ptr->outqueue);
         tipc_link_reset_fragments(l_ptr);
 }
@@ -433,7 +434,7 @@ void tipc_link_reset(struct tipc_link *l_ptr)
 
         /* Clean up all queues: */
         __skb_queue_purge(&l_ptr->outqueue);
-        kfree_skb_list(l_ptr->oldest_deferred_in);
+        __skb_queue_purge(&l_ptr->deferred_queue);
         if (!skb_queue_empty(&l_ptr->waiting_sks)) {
                 skb_queue_splice_init(&l_ptr->waiting_sks, &owner->waiting_sks);
                 owner->action_flags |= TIPC_WAKEUP_USERS;
@@ -442,9 +443,6 @@ void tipc_link_reset(struct tipc_link *l_ptr)
         l_ptr->unacked_window = 0;
         l_ptr->checkpoint = 1;
         l_ptr->next_out_no = 1;
-        l_ptr->deferred_inqueue_sz = 0;
-        l_ptr->oldest_deferred_in = NULL;
-        l_ptr->newest_deferred_in = NULL;
         l_ptr->fsm_msg_cnt = 0;
         l_ptr->stale_count = 0;
         link_reset_statistics(l_ptr);
@@ -974,19 +972,23 @@ void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *skb,
 static struct sk_buff *link_insert_deferred_queue(struct tipc_link *l_ptr,
                                                   struct sk_buff *buf)
 {
+        struct sk_buff_head head;
+        struct sk_buff *skb = NULL;
         u32 seq_no;
 
-        if (l_ptr->oldest_deferred_in == NULL)
+        if (skb_queue_empty(&l_ptr->deferred_queue))
                 return buf;
 
-        seq_no = buf_seqno(l_ptr->oldest_deferred_in);
+        seq_no = buf_seqno(skb_peek(&l_ptr->deferred_queue));
         if (seq_no == mod(l_ptr->next_in_no)) {
-                l_ptr->newest_deferred_in->next = buf;
-                buf = l_ptr->oldest_deferred_in;
-                l_ptr->oldest_deferred_in = NULL;
-                l_ptr->deferred_inqueue_sz = 0;
+                __skb_queue_head_init(&head);
+                skb_queue_splice_tail_init(&l_ptr->deferred_queue, &head);
+                skb = head.next;
+                skb->prev = NULL;
+                head.prev->next = buf;
+                head.prev->prev = NULL;
         }
-        return buf;
+        return skb;
 }
 
 /**
@@ -1170,7 +1172,7 @@ void tipc_rcv(struct sk_buff *head, struct tipc_bearer *b_ptr)
                         continue;
                 }
                 l_ptr->next_in_no++;
-                if (unlikely(l_ptr->oldest_deferred_in))
+                if (unlikely(!skb_queue_empty(&l_ptr->deferred_queue)))
                         head = link_insert_deferred_queue(l_ptr, head);
 
                 if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
@@ -1273,48 +1275,37 @@ static int tipc_link_input(struct tipc_link *l, struct sk_buff *buf)
  *
  * Returns increase in queue length (i.e. 0 or 1)
  */
-u32 tipc_link_defer_pkt(struct sk_buff **head, struct sk_buff **tail,
-                        struct sk_buff *buf)
+u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *skb)
 {
-        struct sk_buff *queue_buf;
-        struct sk_buff **prev;
-        u32 seq_no = buf_seqno(buf);
-
-        buf->next = NULL;
+        struct sk_buff *skb1;
+        u32 seq_no = buf_seqno(skb);
 
         /* Empty queue ? */
-        if (*head == NULL) {
-                *head = *tail = buf;
+        if (skb_queue_empty(list)) {
+                __skb_queue_tail(list, skb);
                 return 1;
         }
 
         /* Last ? */
-        if (less(buf_seqno(*tail), seq_no)) {
-                (*tail)->next = buf;
-                *tail = buf;
+        if (less(buf_seqno(skb_peek_tail(list)), seq_no)) {
+                __skb_queue_tail(list, skb);
                 return 1;
         }
 
         /* Locate insertion point in queue, then insert; discard if duplicate */
-        prev = head;
-        queue_buf = *head;
-        for (;;) {
-                u32 curr_seqno = buf_seqno(queue_buf);
+        skb_queue_walk(list, skb1) {
+                u32 curr_seqno = buf_seqno(skb1);
 
                 if (seq_no == curr_seqno) {
-                        kfree_skb(buf);
+                        kfree_skb(skb);
                         return 0;
                 }
 
                 if (less(seq_no, curr_seqno))
                         break;
-
-                prev = &queue_buf->next;
-                queue_buf = queue_buf->next;
         }
 
-        buf->next = queue_buf;
-        *prev = buf;
+        __skb_queue_before(list, skb1, skb);
         return 1;
 }
 
@@ -1344,15 +1335,14 @@ static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
                 return;
         }
 
-        if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
-                                &l_ptr->newest_deferred_in, buf)) {
-                l_ptr->deferred_inqueue_sz++;
+        if (tipc_link_defer_pkt(&l_ptr->deferred_queue, buf)) {
                 l_ptr->stats.deferred_recv++;
                 TIPC_SKB_CB(buf)->deferred = true;
-                if ((l_ptr->deferred_inqueue_sz % 16) == 1)
+                if ((skb_queue_len(&l_ptr->deferred_queue) % 16) == 1)
                         tipc_link_proto_xmit(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
-        } else
+        } else {
                 l_ptr->stats.duplicates++;
+        }
 }
 
 /*
@@ -1388,8 +1378,8 @@ void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int probe_msg,
                 if (l_ptr->next_out)
                         next_sent = buf_seqno(l_ptr->next_out);
                 msg_set_next_sent(msg, next_sent);
-                if (l_ptr->oldest_deferred_in) {
-                        u32 rec = buf_seqno(l_ptr->oldest_deferred_in);
+                if (!skb_queue_empty(&l_ptr->deferred_queue)) {
+                        u32 rec = buf_seqno(skb_peek(&l_ptr->deferred_queue));
                         gap = mod(rec - mod(l_ptr->next_in_no));
                 }
                 msg_set_seq_gap(msg, gap);
diff --git a/net/tipc/link.h b/net/tipc/link.h
index 96f1e1bf0798..de7b8833641a 100644
--- a/net/tipc/link.h
+++ b/net/tipc/link.h
@@ -124,9 +124,7 @@ struct tipc_stats {
  * @last_retransmitted: sequence number of most recently retransmitted message
  * @stale_count: # of identical retransmit requests made by peer
  * @next_in_no: next sequence number to expect for inbound messages
- * @deferred_inqueue_sz: # of messages in inbound message queue
- * @oldest_deferred_in: ptr to first inbound message in queue
- * @newest_deferred_in: ptr to last inbound message in queue
+ * @deferred_queue: deferred queue saved OOS b'cast message received from node
  * @unacked_window: # of inbound messages rx'd without ack'ing back to peer
  * @next_out: ptr to first unsent outbound message in queue
  * @waiting_sks: linked list of sockets waiting for link congestion to abate
@@ -178,9 +176,7 @@ struct tipc_link {
 
         /* Reception */
         u32 next_in_no;
-        u32 deferred_inqueue_sz;
-        struct sk_buff *oldest_deferred_in;
-        struct sk_buff *newest_deferred_in;
+        struct sk_buff_head deferred_queue;
         u32 unacked_window;
 
         /* Congestion handling */
@@ -224,8 +220,7 @@ void tipc_link_bundle_rcv(struct sk_buff *buf);
 void tipc_link_proto_xmit(struct tipc_link *l_ptr, u32 msg_typ, int prob,
                           u32 gap, u32 tolerance, u32 priority, u32 acked_mtu);
 void tipc_link_push_packets(struct tipc_link *l_ptr);
-u32 tipc_link_defer_pkt(struct sk_buff **head, struct sk_buff **tail,
-                        struct sk_buff *buf);
+u32 tipc_link_defer_pkt(struct sk_buff_head *list, struct sk_buff *buf);
 void tipc_link_set_queue_limits(struct tipc_link *l_ptr, u32 window);
 void tipc_link_retransmit(struct tipc_link *l_ptr,
                           struct sk_buff *start, u32 retransmits);
diff --git a/net/tipc/node.c b/net/tipc/node.c
index 17b8092f9c40..69b96be09a86 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -116,6 +116,7 @@ struct tipc_node *tipc_node_create(u32 addr)
         INIT_LIST_HEAD(&n_ptr->publ_list);
         INIT_LIST_HEAD(&n_ptr->conn_sks);
         __skb_queue_head_init(&n_ptr->waiting_sks);
+        __skb_queue_head_init(&n_ptr->bclink.deferred_queue);
 
         hlist_add_head_rcu(&n_ptr->hash, &node_htable[tipc_hashfn(addr)]);
 
@@ -381,8 +382,7 @@ static void node_lost_contact(struct tipc_node *n_ptr)
 
         /* Flush broadcast link info associated with lost node */
         if (n_ptr->bclink.recv_permitted) {
-                kfree_skb_list(n_ptr->bclink.deferred_head);
-                n_ptr->bclink.deferred_size = 0;
+                __skb_queue_purge(&n_ptr->bclink.deferred_queue);
 
                 if (n_ptr->bclink.reasm_buf) {
                         kfree_skb(n_ptr->bclink.reasm_buf);
diff --git a/net/tipc/node.h b/net/tipc/node.h
index f1994511f033..cbe0e950f1cc 100644
--- a/net/tipc/node.h
+++ b/net/tipc/node.h
@@ -71,9 +71,7 @@ enum {
  * @last_in: sequence # of last in-sequence b'cast message received from node
  * @last_sent: sequence # of last b'cast message sent by node
  * @oos_state: state tracker for handling OOS b'cast messages
- * @deferred_size: number of OOS b'cast messages in deferred queue
- * @deferred_head: oldest OOS b'cast message received from node
- * @deferred_tail: newest OOS b'cast message received from node
+ * @deferred_queue: deferred queue saved OOS b'cast message received from node
  * @reasm_buf: broadcast reassembly queue head from node
  * @recv_permitted: true if node is allowed to receive b'cast messages
  */
@@ -83,8 +81,7 @@ struct tipc_node_bclink {
         u32 last_sent;
         u32 oos_state;
         u32 deferred_size;
-        struct sk_buff *deferred_head;
-        struct sk_buff *deferred_tail;
+        struct sk_buff_head deferred_queue;
         struct sk_buff *reasm_buf;
         bool recv_permitted;
 };