Add notes to autoservice and pbx doxygen regarding a potential

deadlock scenario so that it is avoided in the future



git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@164416 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/channel.h

@@ -1187,6 +1187,11 @@ int ast_autoservice_start(struct ast_channel *chan);
 /*! 
  * \brief Stop servicing a channel for us...  
  *
+ * \note if chan is locked prior to calling ast_autoservice_stop, it
+ * is likely that there will be a deadlock between the thread that calls
+ * ast_autoservice_stop and the autoservice thread. It is important
+ * that chan is not locked prior to this call
+ *
  * \retval 0 success
  * \retval -1 error, or the channel has been hungup 
  */

include/asterisk/pbx.h

@@ -383,6 +383,10 @@ int ast_get_hint(char *hint, int maxlen, char *name, int maxnamelen,
  * \param priority priority of the action within the extension
  * \param callerid callerid to search for
  *
+ * \note It is possible for autoservice to be started and stopped on c during this
+ * function call, it is important that c is not locked prior to calling this. Otherwise
+ * a deadlock may occur
+ *
  * \return If an extension within the given context(or callerid) with the given priority 
  *         is found a non zero value will be returned. Otherwise, 0 is returned.
  */
@@ -398,6 +402,10 @@ int ast_exists_extension(struct ast_channel *c, const char *context, const char
  * \param label label of the action within the extension to match to priority
  * \param callerid callerid to search for
  *
+ * \note It is possible for autoservice to be started and stopped on c during this
+ * function call, it is important that c is not locked prior to calling this. Otherwise
+ * a deadlock may occur
+ *
  * \return the priority which matches the given label in the extension or -1 if not found.
  */
 int ast_findlabel_extension(struct ast_channel *c, const char *context, 
@@ -406,6 +414,10 @@ int ast_findlabel_extension(struct ast_channel *c, const char *context,
 /*!
  * \brief Find the priority of an extension that has the specified label
  *
+ * \note It is possible for autoservice to be started and stopped on c during this
+ * function call, it is important that c is not locked prior to calling this. Otherwise
+ * a deadlock may occur
+ *
  * \note This function is the same as ast_findlabel_extension, except that it accepts
  * a pointer to an ast_context structure to specify the context instead of the
  * name of the context. Otherwise, the functions behave the same.
@@ -422,6 +434,10 @@ int ast_findlabel_extension2(struct ast_channel *c, struct ast_context *con,
  * \param priority priority of extension path
  * \param callerid callerid of extension being searched for
  *
+ * \note It is possible for autoservice to be started and stopped on c during this
+ * function call, it is important that c is not locked prior to calling this. Otherwise
+ * a deadlock may occur
+ *
  * \return If "exten" *could be* a valid extension in this context with or without
  * some more digits, return non-zero.  Basically, when this returns 0, no matter
  * what you add to exten, it's not going to be a valid extension anymore
@@ -438,6 +454,10 @@ int ast_canmatch_extension(struct ast_channel *c, const char *context,
  * \param priority priority of extension path
  * \param callerid callerid of extension being searched for
  *
+ * \note It is possible for autoservice to be started and stopped on c during this
+ * function call, it is important that c is not locked prior to calling this. Otherwise
+ * a deadlock may occur
+ *
  * \return If "exten" *could match* a valid extension in this context with
  * some more digits, return non-zero.  Does NOT return non-zero if this is
  * an exact-match only.  Basically, when this returns 0, no matter