Perform deadlock avoidance on initial entry, too

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@3343 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channel.c b/channel.c
index 510e0c0d12862ec177e8ded1f67369e120bbebb6..4447c2755934e8a347c2568a6a5c96016df0e3b7 100755 (executable)
--- a/channel.c
+++ b/channel.c
@@ -451,14 +451,28 @@ void ast_channel_undefer_dtmf(struct ast_channel *chan)
 struct ast_channel *ast_channel_walk_locked(struct ast_channel *prev)
 {
        /* Returns next channel (locked) */
-       struct ast_channel *l, *ret=NULL;
+       struct ast_channel *l, *ret;
        int retries = 0;        
 retry:
+       ret=NULL;
        ast_mutex_lock(&chlock);
        l = channels;
        if (!prev) {
-               if (l)
-                       ast_mutex_lock(&l->lock);
+               if (l) {
+                       if (ast_mutex_trylock(&l->lock)) {
+                               if (retries < 10)
+                                       ast_log(LOG_DEBUG, "Avoiding initial deadlock for '%s'\n", ret->name);
+                               else
+                                       ast_log(LOG_WARNING, "Avoided initial deadlock for '%s', %d retries!\n", ret->name, retries);
+                               ast_mutex_unlock(&chlock);
+                               if (retries < 10) {
+                                       usleep(1);
+                                       retries++;
+                                       goto retry;
+                               } else
+                                       return NULL;
+                       }
+               }
                ast_mutex_unlock(&chlock);
                return l;
        }