1 files changed, 87 insertions, 142 deletions

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 13b987745820..da6018beb6eb 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1,7 +1,7 @@
 /*
  * net/tipc/link.c: TIPC link code
  *
- * Copyright (c) 1996-2007, 2012, Ericsson AB
+ * Copyright (c) 1996-2007, 2012-2014, Ericsson AB
  * Copyright (c) 2004-2007, 2010-2013, Wind River Systems
  * All rights reserved.
  *
@@ -78,8 +78,8 @@ static const char *link_unk_evt = "Unknown link event ";
 static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
                                        struct sk_buff *buf);
 static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf);
-static int  link_recv_changeover_msg(struct tipc_link **l_ptr,
-                                     struct sk_buff **buf);
+static int  tipc_link_tunnel_rcv(struct tipc_link **l_ptr,
+                                 struct sk_buff **buf);
 static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance);
 static int  link_send_sections_long(struct tipc_port *sender,
                                     struct iovec const *msg_sect,
@@ -87,7 +87,6 @@ static int  link_send_sections_long(struct tipc_port *sender,
 static void link_state_event(struct tipc_link *l_ptr, u32 event);
 static void link_reset_statistics(struct tipc_link *l_ptr);
 static void link_print(struct tipc_link *l_ptr, const char *str);
-static void link_start(struct tipc_link *l_ptr);
 static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf);
 static void tipc_link_send_sync(struct tipc_link *l);
 static void tipc_link_recv_sync(struct tipc_node *n, struct sk_buff *buf);
@@ -278,9 +277,11 @@ struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
 
         tipc_node_attach_link(n_ptr, l_ptr);
 
-        k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
+        k_init_timer(&l_ptr->timer, (Handler)link_timeout,
+                     (unsigned long)l_ptr);
         list_add_tail(&l_ptr->link_list, &b_ptr->links);
-        tipc_k_signal((Handler)link_start, (unsigned long)l_ptr);
+
+        link_state_event(l_ptr, STARTING_EVT);
 
         return l_ptr;
 }
@@ -305,19 +306,13 @@ void tipc_link_delete(struct tipc_link *l_ptr)
         tipc_node_lock(l_ptr->owner);
         tipc_link_reset(l_ptr);
         tipc_node_detach_link(l_ptr->owner, l_ptr);
-        tipc_link_stop(l_ptr);
+        tipc_link_purge_queues(l_ptr);
         list_del_init(&l_ptr->link_list);
         tipc_node_unlock(l_ptr->owner);
         k_term_timer(&l_ptr->timer);
         kfree(l_ptr);
 }
 
-static void link_start(struct tipc_link *l_ptr)
-{
-        tipc_node_lock(l_ptr->owner);
-        link_state_event(l_ptr, STARTING_EVT);
-        tipc_node_unlock(l_ptr->owner);
-}
 
 /**
  * link_schedule_port - schedule port for deferred sending
@@ -386,14 +381,7 @@ exit:
  */
 static void link_release_outqueue(struct tipc_link *l_ptr)
 {
-        struct sk_buff *buf = l_ptr->first_out;
-        struct sk_buff *next;
-
-        while (buf) {
-                next = buf->next;
-                kfree_skb(buf);
-                buf = next;
-        }
+        kfree_skb_list(l_ptr->first_out);
         l_ptr->first_out = NULL;
         l_ptr->out_queue_size = 0;
 }
@@ -410,37 +398,20 @@ void tipc_link_reset_fragments(struct tipc_link *l_ptr)
 }
 
 /**
- * tipc_link_stop - purge all inbound and outbound messages associated with link
+ * tipc_link_purge_queues - purge all pkt queues associated with link
  * @l_ptr: pointer to link
  */
-void tipc_link_stop(struct tipc_link *l_ptr)
+void tipc_link_purge_queues(struct tipc_link *l_ptr)
 {
-        struct sk_buff *buf;
-        struct sk_buff *next;
-
-        buf = l_ptr->oldest_deferred_in;
-        while (buf) {
-                next = buf->next;
-                kfree_skb(buf);
-                buf = next;
-        }
-
-        buf = l_ptr->first_out;
-        while (buf) {
-                next = buf->next;
-                kfree_skb(buf);
-                buf = next;
-        }
-
+        kfree_skb_list(l_ptr->oldest_deferred_in);
+        kfree_skb_list(l_ptr->first_out);
         tipc_link_reset_fragments(l_ptr);
-
         kfree_skb(l_ptr->proto_msg_queue);
         l_ptr->proto_msg_queue = NULL;
 }
 
 void tipc_link_reset(struct tipc_link *l_ptr)
 {
-        struct sk_buff *buf;
         u32 prev_state = l_ptr->state;
         u32 checkpoint = l_ptr->next_in_no;
         int was_active_link = tipc_link_is_active(l_ptr);
@@ -461,8 +432,7 @@ void tipc_link_reset(struct tipc_link *l_ptr)
         tipc_node_link_down(l_ptr->owner, l_ptr);
         tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
 
-        if (was_active_link && tipc_node_active_links(l_ptr->owner) &&
-            l_ptr->owner->permit_changeover) {
+        if (was_active_link && tipc_node_active_links(l_ptr->owner)) {
                 l_ptr->reset_checkpoint = checkpoint;
                 l_ptr->exp_msg_count = START_CHANGEOVER;
         }
@@ -471,12 +441,7 @@ void tipc_link_reset(struct tipc_link *l_ptr)
         link_release_outqueue(l_ptr);
         kfree_skb(l_ptr->proto_msg_queue);
         l_ptr->proto_msg_queue = NULL;
-        buf = l_ptr->oldest_deferred_in;
-        while (buf) {
-                struct sk_buff *next = buf->next;
-                kfree_skb(buf);
-                buf = next;
-        }
+        kfree_skb_list(l_ptr->oldest_deferred_in);
         if (!list_empty(&l_ptr->waiting_ports))
                 tipc_link_wakeup_ports(l_ptr, 1);
 
@@ -517,10 +482,11 @@ static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
         if (!l_ptr->started && (event != STARTING_EVT))
                 return;         /* Not yet. */
 
-        if (link_blocked(l_ptr)) {
+        /* Check whether changeover is going on */
+        if (l_ptr->exp_msg_count) {
                 if (event == TIMEOUT_EVT)
                         link_set_timer(l_ptr, cont_intv);
-                return;   /* Changeover going on */
+                return;
         }
 
         switch (l_ptr->state) {
@@ -790,8 +756,7 @@ int tipc_link_send_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
                 return link_send_long_buf(l_ptr, buf);
 
         /* Packet can be queued or sent. */
-        if (likely(!tipc_bearer_blocked(l_ptr->b_ptr) &&
-                   !link_congested(l_ptr))) {
+        if (likely(!link_congested(l_ptr))) {
                 link_add_to_outqueue(l_ptr, buf, msg);
 
                 tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
@@ -957,14 +922,13 @@ static int link_send_buf_fast(struct tipc_link *l_ptr, struct sk_buff *buf,
 
         if (likely(!link_congested(l_ptr))) {
                 if (likely(msg_size(msg) <= l_ptr->max_pkt)) {
-                        if (likely(!tipc_bearer_blocked(l_ptr->b_ptr))) {
-                                link_add_to_outqueue(l_ptr, buf, msg);
-                                tipc_bearer_send(l_ptr->b_ptr, buf,
-                                                 &l_ptr->media_addr);
-                                l_ptr->unacked_window = 0;
-                                return res;
-                        }
-                } else
+                        link_add_to_outqueue(l_ptr, buf, msg);
+                        tipc_bearer_send(l_ptr->b_ptr, buf,
+                                         &l_ptr->media_addr);
+                        l_ptr->unacked_window = 0;
+                        return res;
+                }
+                else
                         *used_max_pkt = l_ptr->max_pkt;
         }
         return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
@@ -1013,8 +977,7 @@ exit:
                         }
 
                         /* Exit if link (or bearer) is congested */
-                        if (link_congested(l_ptr) ||
-                            tipc_bearer_blocked(l_ptr->b_ptr)) {
+                        if (link_congested(l_ptr)) {
                                 res = link_schedule_port(l_ptr,
                                                          sender->ref, res);
                                 goto exit;
@@ -1127,10 +1090,7 @@ again:
                 if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
                         res = -EFAULT;
 error:
-                        for (; buf_chain; buf_chain = buf) {
-                                buf = buf_chain->next;
-                                kfree_skb(buf_chain);
-                        }
+                        kfree_skb_list(buf_chain);
                         return res;
                 }
                 sect_crs += sz;
@@ -1180,18 +1140,12 @@ error:
                 if (l_ptr->max_pkt < max_pkt) {
                         sender->max_pkt = l_ptr->max_pkt;
                         tipc_node_unlock(node);
-                        for (; buf_chain; buf_chain = buf) {
-                                buf = buf_chain->next;
-                                kfree_skb(buf_chain);
-                        }
+                        kfree_skb_list(buf_chain);
                         goto again;
                 }
         } else {
 reject:
-                for (; buf_chain; buf_chain = buf) {
-                        buf = buf_chain->next;
-                        kfree_skb(buf_chain);
-                }
+                kfree_skb_list(buf_chain);
                 return tipc_port_reject_sections(sender, hdr, msg_sect,
                                                  len, TIPC_ERR_NO_NODE);
         }
@@ -1209,7 +1163,7 @@ reject:
 /*
  * tipc_link_push_packet: Push one unsent packet to the media
  */
-u32 tipc_link_push_packet(struct tipc_link *l_ptr)
+static u32 tipc_link_push_packet(struct tipc_link *l_ptr)
 {
         struct sk_buff *buf = l_ptr->first_out;
         u32 r_q_size = l_ptr->retransm_queue_size;
@@ -1281,9 +1235,6 @@ void tipc_link_push_queue(struct tipc_link *l_ptr)
 {
         u32 res;
 
-        if (tipc_bearer_blocked(l_ptr->b_ptr))
-                return;
-
         do {
                 res = tipc_link_push_packet(l_ptr);
         } while (!res);
@@ -1370,26 +1321,15 @@ void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *buf,
 
         msg = buf_msg(buf);
 
-        if (tipc_bearer_blocked(l_ptr->b_ptr)) {
-                if (l_ptr->retransm_queue_size == 0) {
-                        l_ptr->retransm_queue_head = msg_seqno(msg);
-                        l_ptr->retransm_queue_size = retransmits;
-                } else {
-                        pr_err("Unexpected retransmit on link %s (qsize=%d)\n",
-                               l_ptr->name, l_ptr->retransm_queue_size);
+        /* Detect repeated retransmit failures */
+        if (l_ptr->last_retransmitted == msg_seqno(msg)) {
+                if (++l_ptr->stale_count > 100) {
+                        link_retransmit_failure(l_ptr, buf);
+                        return;
                 }
-                return;
         } else {
-                /* Detect repeated retransmit failures on unblocked bearer */
-                if (l_ptr->last_retransmitted == msg_seqno(msg)) {
-                        if (++l_ptr->stale_count > 100) {
-                                link_retransmit_failure(l_ptr, buf);
-                                return;
-                        }
-                } else {
-                        l_ptr->last_retransmitted = msg_seqno(msg);
-                        l_ptr->stale_count = 1;
-                }
+                l_ptr->last_retransmitted = msg_seqno(msg);
+                l_ptr->stale_count = 1;
         }
 
         while (retransmits && (buf != l_ptr->next_out) && buf) {
@@ -1451,6 +1391,12 @@ static int link_recv_buf_validate(struct sk_buff *buf)
         u32 hdr_size;
         u32 min_hdr_size;
 
+        /* If this packet comes from the defer queue, the skb has already
+         * been validated
+         */
+        if (unlikely(TIPC_SKB_CB(buf)->deferred))
+                return 1;
+
         if (unlikely(buf->len < MIN_H_SIZE))
                 return 0;
 
@@ -1476,14 +1422,14 @@ static int link_recv_buf_validate(struct sk_buff *buf)
 }
 
 /**
- * tipc_recv_msg - process TIPC messages arriving from off-node
+ * tipc_rcv - process TIPC packets/messages arriving from off-node
  * @head: pointer to message buffer chain
  * @tb_ptr: pointer to bearer message arrived on
  *
  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
  * structure (i.e. cannot be NULL), but bearer can be inactive.
  */
-void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *b_ptr)
+void tipc_rcv(struct sk_buff *head, struct tipc_bearer *b_ptr)
 {
         read_lock_bh(&tipc_net_lock);
         while (head) {
@@ -1658,7 +1604,7 @@ deliver:
                         continue;
                 case CHANGEOVER_PROTOCOL:
                         type = msg_type(msg);
-                        if (link_recv_changeover_msg(&l_ptr, &buf)) {
+                        if (tipc_link_tunnel_rcv(&l_ptr, &buf)) {
                                 msg = buf_msg(buf);
                                 seq_no = msg_seqno(msg);
                                 if (type == ORIGINAL_MSG)
@@ -1763,6 +1709,7 @@ static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
                                 &l_ptr->newest_deferred_in, buf)) {
                 l_ptr->deferred_inqueue_sz++;
                 l_ptr->stats.deferred_recv++;
+                TIPC_SKB_CB(buf)->deferred = true;
                 if ((l_ptr->deferred_inqueue_sz % 16) == 1)
                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
         } else
@@ -1787,7 +1734,8 @@ void tipc_link_send_proto_msg(struct tipc_link *l_ptr, u32 msg_typ,
                 l_ptr->proto_msg_queue = NULL;
         }
 
-        if (link_blocked(l_ptr))
+        /* Don't send protocol message during link changeover */
+        if (l_ptr->exp_msg_count)
                 return;
 
         /* Abort non-RESET send if communication with node is prohibited */
@@ -1862,12 +1810,6 @@ void tipc_link_send_proto_msg(struct tipc_link *l_ptr, u32 msg_typ,
         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
         buf->priority = TC_PRIO_CONTROL;
 
-        /* Defer message if bearer is already blocked */
-        if (tipc_bearer_blocked(l_ptr->b_ptr)) {
-                l_ptr->proto_msg_queue = buf;
-                return;
-        }
-
         tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr);
         l_ptr->unacked_window = 0;
         kfree_skb(buf);
@@ -1886,7 +1828,8 @@ static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf)
         u32 msg_tol;
         struct tipc_msg *msg = buf_msg(buf);
 
-        if (link_blocked(l_ptr))
+        /* Discard protocol message during link changeover */
+        if (l_ptr->exp_msg_count)
                 goto exit;
 
         /* record unnumbered packet arrival (force mismatch on next timeout) */
@@ -1896,8 +1839,6 @@ static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf)
                 if (tipc_own_addr > msg_prevnode(msg))
                         l_ptr->b_ptr->net_plane = msg_net_plane(msg);
 
-        l_ptr->owner->permit_changeover = msg_redundant_link(msg);
-
         switch (msg_type(msg)) {
 
         case RESET_MSG:
@@ -2013,13 +1954,13 @@ exit:
 }
 
 
-/*
- * tipc_link_tunnel(): Send one message via a link belonging to
- * another bearer. Owner node is locked.
+/* tipc_link_tunnel_xmit(): Tunnel one packet via a link belonging to
+ * a different bearer. Owner node is locked.
  */
-static void tipc_link_tunnel(struct tipc_link *l_ptr,
-                             struct tipc_msg *tunnel_hdr, struct tipc_msg *msg,
-                             u32 selector)
+static void tipc_link_tunnel_xmit(struct tipc_link *l_ptr,
+                                  struct tipc_msg *tunnel_hdr,
+                                  struct tipc_msg *msg,
+                                  u32 selector)
 {
         struct tipc_link *tunnel;
         struct sk_buff *buf;
@@ -2042,12 +1983,13 @@ static void tipc_link_tunnel(struct tipc_link *l_ptr,
 }
 
 
-
-/*
- * changeover(): Send whole message queue via the remaining link
- *               Owner node is locked.
+/* tipc_link_failover_send_queue(): A link has gone down, but a second
+ * link is still active. We can do failover. Tunnel the failing link's
+ * whole send queue via the remaining link. This way, we don't lose
+ * any packets, and sequence order is preserved for subsequent traffic
+ * sent over the remaining link. Owner node is locked.
  */
-void tipc_link_changeover(struct tipc_link *l_ptr)
+void tipc_link_failover_send_queue(struct tipc_link *l_ptr)
 {
         u32 msgcount = l_ptr->out_queue_size;
         struct sk_buff *crs = l_ptr->first_out;
@@ -2058,11 +2000,6 @@ void tipc_link_changeover(struct tipc_link *l_ptr)
         if (!tunnel)
                 return;
 
-        if (!l_ptr->owner->permit_changeover) {
-                pr_warn("%speer did not permit changeover\n", link_co_err);
-                return;
-        }
-
         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
                  ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
@@ -2096,20 +2033,30 @@ void tipc_link_changeover(struct tipc_link *l_ptr)
                         msgcount = msg_msgcnt(msg);
                         while (msgcount--) {
                                 msg_set_seqno(m, msg_seqno(msg));
-                                tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
-                                                 msg_link_selector(m));
+                                tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, m,
+                                                      msg_link_selector(m));
                                 pos += align(msg_size(m));
                                 m = (struct tipc_msg *)pos;
                         }
                 } else {
-                        tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
-                                         msg_link_selector(msg));
+                        tipc_link_tunnel_xmit(l_ptr, &tunnel_hdr, msg,
+                                              msg_link_selector(msg));
                 }
                 crs = crs->next;
         }
 }
 
-void tipc_link_send_duplicate(struct tipc_link *l_ptr, struct tipc_link *tunnel)
+/* tipc_link_dup_send_queue(): A second link has become active. Tunnel a
+ * duplicate of the first link's send queue via the new link. This way, we
+ * are guaranteed that currently queued packets from a socket are delivered
+ * before future traffic from the same socket, even if this is using the
+ * new link. The last arriving copy of each duplicate packet is dropped at
+ * the receiving end by the regular protocol check, so packet cardinality
+ * and sequence order is preserved per sender/receiver socket pair.
+ * Owner node is locked.
+ */
+void tipc_link_dup_send_queue(struct tipc_link *l_ptr,
+                              struct tipc_link *tunnel)
 {
         struct sk_buff *iter;
         struct tipc_msg tunnel_hdr;
@@ -2165,12 +2112,14 @@ static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
         return eb;
 }
 
-/*
- *  link_recv_changeover_msg(): Receive tunneled packet sent
- *  via other link. Node is locked. Return extracted buffer.
+/*  tipc_link_tunnel_rcv(): Receive a tunneled packet, sent
+ *  via other link as result of a failover (ORIGINAL_MSG) or
+ *  a new active link (DUPLICATE_MSG). Failover packets are
+ *  returned to the active link for delivery upwards.
+ *  Owner node is locked.
  */
-static int link_recv_changeover_msg(struct tipc_link **l_ptr,
-                                    struct sk_buff **buf)
+static int tipc_link_tunnel_rcv(struct tipc_link **l_ptr,
+                                struct sk_buff **buf)
 {
         struct sk_buff *tunnel_buf = *buf;
         struct tipc_link *dest_link;
@@ -2307,11 +2256,7 @@ static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
                 fragm = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
                 if (fragm == NULL) {
                         kfree_skb(buf);
-                        while (buf_chain) {
-                                buf = buf_chain;
-                                buf_chain = buf_chain->next;
-                                kfree_skb(buf);
-                        }
+                        kfree_skb_list(buf_chain);
                         return -ENOMEM;
                 }
                 msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);