Fix swap_subs for better locking

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@2746 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_zap.c b/channels/chan_zap.c
index b9c3780..b8de9ae 100755 (executable)
--- a/channels/chan_zap.c
+++ b/channels/chan_zap.c
@@ -618,12 +618,29 @@ static int zt_get_index(struct ast_channel *ast, struct zt_pvt *p, int nullok)
        return res;
 }
 
+static void wakeup_sub(struct zt_pvt *p, int a)
+{
+       struct ast_frame null = { AST_FRAME_NULL, };
+       for (;;) {
+               if (p->subs[a].owner) {
+                       if (ast_mutex_trylock(&p->subs[a].owner->lock)) {
+                               ast_mutex_unlock(&p->lock);
+                               usleep(1);
+                               ast_mutex_lock(&p->lock);
+                       } else {
+                               ast_queue_frame(p->subs[a].owner, &null);
+                               ast_mutex_unlock(&p->subs[a].owner->lock);
+                       }
+               } else
+                       break;
+       }
+}
+
 static void swap_subs(struct zt_pvt *p, int a, int b)
 {
        int tchan;
        int tinthreeway;
        struct ast_channel *towner;
-       struct ast_frame null = { AST_FRAME_NULL, };
 
        ast_log(LOG_DEBUG, "Swapping %d and %d\n", a, b);
 
@@ -639,15 +656,12 @@ static void swap_subs(struct zt_pvt *p, int a, int b)
        p->subs[b].owner = towner;
        p->subs[b].inthreeway = tinthreeway;
 
-       if (p->subs[a].owner) {
+       if (p->subs[a].owner) 
                p->subs[a].owner->fds[0] = p->subs[a].zfd;
-               ast_queue_frame(p->subs[a].owner, &null);
-       }
-       if (p->subs[b].owner) {
+       if (p->subs[b].owner) 
                p->subs[b].owner->fds[0] = p->subs[b].zfd;
-               ast_queue_frame(p->subs[b].owner, &null);
-       }
-       
+       wakeup_sub(p, a);
+       wakeup_sub(p, b);
 }
 
 static int zt_open(char *fn)