Modify ast_answer() to not hold the channel lock while calling ast_safe_sleep()

or when calling ast_waitfor().  These are inappropriate times to hold the channel
lock.  This is what has caused "could not get the channel lock" messages from
chan_sip and has likely caused a negative impact on performance results of SIP
in Asterisk 1.6.  Thanks to file for pointing out this section of code.

(closes issue #13287)
(closes issue #13115)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@141949 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/main/channel.c b/main/channel.c
index b19c4c9..fd496e5 100644 (file)
--- a/main/channel.c
+++ b/main/channel.c
@@ -1674,16 +1674,21 @@ int __ast_answer(struct ast_channel *chan, unsigned int delay)
                return -1;
        }
 
+       ast_channel_unlock(chan);
+
        switch (chan->_state) {
        case AST_STATE_RINGING:
        case AST_STATE_RING:
-               if (chan->tech->answer)
+               ast_channel_lock(chan);
+               if (chan->tech->answer) {
                        res = chan->tech->answer(chan);
+               }
                ast_setstate(chan, AST_STATE_UP);
                ast_cdr_answer(chan->cdr);
-               if (delay)
+               ast_channel_unlock(chan);
+               if (delay) {
                        ast_safe_sleep(chan, delay);
-               else {
+               } else {
                        struct ast_frame *f;
                        int ms = ANSWER_WAIT_MS;
                        while (1) {
@@ -1719,8 +1724,8 @@ int __ast_answer(struct ast_channel *chan, unsigned int delay)
        default:
                break;
        }
+
        chan->visible_indication = 0;
-       ast_channel_unlock(chan);
 
        return res;
 }