Merge master.kernel.org:/pub/scm/linux/kernel/git/mchehab/v4l-dvb

[cascardo/linux.git] / net / tipc / bcast.c

diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 44645f5..5412804 100644 (file)
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -81,7 +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 {
@@ -89,6 +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;
 };
 
 /**
@@ -551,12 +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) */
 
@@ -577,9 +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;
@@ -588,8 +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 &&
@@ -607,27 +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;
 }
 
 /**
@@ -785,7 +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);