1 files changed, 48 insertions, 35 deletions

diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 2c4ecbe50082..1bb75703f384 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -49,13 +49,19 @@
 #include "name_table.h"
 #include "bcast.h"
 
-
 #define MAX_PKT_DEFAULT_MCAST 1500      /* bcast link max packet size (fixed) */
 
 #define BCLINK_WIN_DEFAULT 20           /* bcast link window size (default) */
 
 #define BCLINK_LOG_BUF_SIZE 0
 
+/*
+ * Loss rate for incoming broadcast frames; used to test retransmission code.
+ * Set to N to cause every N'th frame to be discarded; 0 => don't discard any.
+ */
+ 
+#define TIPC_BCAST_LOSS_RATE 0
+
 /**
  * struct bcbearer_pair - a pair of bearers used by broadcast link
  * @primary: pointer to primary bearer
@@ -75,7 +81,14 @@ struct bcbearer_pair {
  * @bearer: (non-standard) broadcast bearer structure
  * @media: (non-standard) broadcast media structure
  * @bpairs: array of bearer pairs
- * @bpairs_temp: array of bearer pairs used during creation of "bpairs"
+ * @bpairs_temp: temporary array of bearer pairs used by tipc_bcbearer_sort()
+ * @remains: temporary node map used by tipc_bcbearer_send()
+ * @remains_new: temporary node map used tipc_bcbearer_send()
+ * 
+ * Note: The fields labelled "temporary" are incorporated into the bearer
+ * to avoid consuming potentially limited stack space through the use of
+ * large local variables within multicast routines.  Concurrent access is
+ * prevented through use of the spinlock "bc_lock".
  */
 
 struct bcbearer {
@@ -83,6 +96,8 @@ struct bcbearer {
         struct media media;
         struct bcbearer_pair bpairs[MAX_BEARERS];
         struct bcbearer_pair bpairs_temp[TIPC_MAX_LINK_PRI + 1];
+        struct node_map remains;
+        struct node_map remains_new;
 };
 
 /**
@@ -102,7 +117,7 @@ struct bclink {
 static struct bcbearer *bcbearer = NULL;
 static struct bclink *bclink = NULL;
 static struct link *bcl = NULL;
-static spinlock_t bc_lock = SPIN_LOCK_UNLOCKED;
+static DEFINE_SPINLOCK(bc_lock);
 
 char tipc_bclink_name[] = "multicast-link";
 
@@ -165,21 +180,18 @@ static int bclink_ack_allowed(u32 n)
  * @after: sequence number of last packet to *not* retransmit
  * @to: sequence number of last packet to retransmit
  * 
- * Called with 'node' locked, bc_lock unlocked
+ * Called with bc_lock locked
  */
 
 static void bclink_retransmit_pkt(u32 after, u32 to)
 {
         struct sk_buff *buf;
 
-        spin_lock_bh(&bc_lock);
         buf = bcl->first_out;
         while (buf && less_eq(buf_seqno(buf), after)) {
                 buf = buf->next;                
         }
-        if (buf != NULL)
-                tipc_link_retransmit(bcl, buf, mod(to - after));
-        spin_unlock_bh(&bc_lock);              
+        tipc_link_retransmit(bcl, buf, mod(to - after));
 }
 
 /** 
@@ -346,8 +358,10 @@ static void tipc_bclink_peek_nack(u32 dest, u32 sender_tag, u32 gap_after, u32 g
                 for (; buf; buf = buf->next) {
                         u32 seqno = buf_seqno(buf);
 
-                        if (mod(seqno - prev) != 1)
+                        if (mod(seqno - prev) != 1) {
                                 buf = NULL;
+                                break;
+                        }
                         if (seqno == gap_after)
                                 break;
                         prev = seqno;
@@ -399,7 +413,10 @@ int tipc_bclink_send_msg(struct sk_buff *buf)
  */
 
 void tipc_bclink_recv_pkt(struct sk_buff *buf)
-{        
+{
+#if (TIPC_BCAST_LOSS_RATE)
+        static int rx_count = 0;
+#endif
         struct tipc_msg *msg = buf_msg(buf);
         struct node* node = tipc_node_find(msg_prevnode(msg));
         u32 next_in;
@@ -420,9 +437,13 @@ void tipc_bclink_recv_pkt(struct sk_buff *buf)
                         tipc_node_lock(node);
                         tipc_bclink_acknowledge(node, msg_bcast_ack(msg));
                         tipc_node_unlock(node);
+                        spin_lock_bh(&bc_lock);
                         bcl->stats.recv_nacks++;
+                        bcl->owner->next = node;   /* remember requestor */
                         bclink_retransmit_pkt(msg_bcgap_after(msg),
                                               msg_bcgap_to(msg));
+                        bcl->owner->next = NULL;
+                        spin_unlock_bh(&bc_lock);              
                 } else {
                         tipc_bclink_peek_nack(msg_destnode(msg),
                                               msg_bcast_tag(msg),
@@ -433,6 +454,14 @@ void tipc_bclink_recv_pkt(struct sk_buff *buf)
                 return;
         }
 
+#if (TIPC_BCAST_LOSS_RATE)
+        if (++rx_count == TIPC_BCAST_LOSS_RATE) {
+                rx_count = 0;
+                buf_discard(buf);
+                return;
+        }
+#endif
+
         tipc_node_lock(node);
 receive:
         deferred = node->bclink.deferred_head;
@@ -531,12 +560,8 @@ static int tipc_bcbearer_send(struct sk_buff *buf,
 {
         static int send_count = 0;
 
-        struct node_map *remains;
-        struct node_map *remains_new;
-        struct node_map *remains_tmp;
         int bp_index;
         int swap_time;
-        int err;
 
         /* Prepare buffer for broadcasting (if first time trying to send it) */
 
@@ -557,9 +582,7 @@ static int tipc_bcbearer_send(struct sk_buff *buf,
 
         /* Send buffer over bearers until all targets reached */
         
-        remains = kmalloc(sizeof(struct node_map), GFP_ATOMIC);
-        remains_new = kmalloc(sizeof(struct node_map), GFP_ATOMIC);
-        *remains = tipc_cltr_bcast_nodes;
+        bcbearer->remains = tipc_cltr_bcast_nodes;
 
         for (bp_index = 0; bp_index < MAX_BEARERS; bp_index++) {
                 struct bearer *p = bcbearer->bpairs[bp_index].primary;
@@ -568,8 +591,8 @@ static int tipc_bcbearer_send(struct sk_buff *buf,
                 if (!p)
                         break;  /* no more bearers to try */
 
-                tipc_nmap_diff(remains, &p->nodes, remains_new);
-                if (remains_new->count == remains->count)
+                tipc_nmap_diff(&bcbearer->remains, &p->nodes, &bcbearer->remains_new);
+                if (bcbearer->remains_new.count == bcbearer->remains.count)
                         continue;       /* bearer pair doesn't add anything */
 
                 if (!p->publ.blocked &&
@@ -587,27 +610,17 @@ swap:
                 bcbearer->bpairs[bp_index].primary = s;
                 bcbearer->bpairs[bp_index].secondary = p;
 update:
-                if (remains_new->count == 0) {
-                        err = TIPC_OK;
-                        goto out;
-                }
+                if (bcbearer->remains_new.count == 0)
+                        return TIPC_OK;
 
-                /* swap map */
-                remains_tmp = remains;
-                remains = remains_new;
-                remains_new = remains_tmp;
+                bcbearer->remains = bcbearer->remains_new;
         }
         
         /* Unable to reach all targets */
 
         bcbearer->bearer.publ.blocked = 1;
         bcl->stats.bearer_congs++;
-        err = ~TIPC_OK;
-
- out:
-        kfree(remains_new);
-        kfree(remains);
-        return err;
+        return ~TIPC_OK;
 }
 
 /**
@@ -765,7 +778,7 @@ int tipc_bclink_init(void)
         bclink = kmalloc(sizeof(*bclink), GFP_ATOMIC);
         if (!bcbearer || !bclink) {
  nomem:
-                warn("Memory squeeze; Failed to create multicast link\n");
+                warn("Multicast link creation failed, no memory\n");
                 kfree(bcbearer);
                 bcbearer = NULL;
                 kfree(bclink);
@@ -783,7 +796,7 @@ int tipc_bclink_init(void)
         memset(bclink, 0, sizeof(struct bclink));
         INIT_LIST_HEAD(&bcl->waiting_ports);
         bcl->next_out_no = 1;
-        bclink->node.lock =  SPIN_LOCK_UNLOCKED;        
+        spin_lock_init(&bclink->node.lock);
         bcl->owner = &bclink->node;
         bcl->max_pkt = MAX_PKT_DEFAULT_MCAST;
         tipc_link_set_queue_limits(bcl, BCLINK_WIN_DEFAULT);