*: remove THREAD_ON macros, add nullity check

The way thread.c is written, a caller who wishes to be able to cancel a
thread or avoid scheduling it twice must keep a reference to the thread.
Typically this is done with a long lived pointer whose value is checked
for null in order to know if the thread is currently scheduled.  The
check-and-schedule idiom is so common that several wrapper macros in
thread.h existed solely to provide it.

This patch removes those macros and adds a new parameter to all
thread_add_* functions which is a pointer to the struct thread * to
store the result of a scheduling call. If the value passed is non-null,
the thread will only be scheduled if the value is null. This helps with
consistency.

A Coccinelle spatch has been used to transform code of the form:

  if (t == NULL)
    t = thread_add_* (...)

to the form

  thread_add_* (..., &t)

The THREAD_ON macros have also been transformed to the underlying
thread.c calls.

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/ospf6d/ospf6_spf.c b/ospf6d/ospf6_spf.c
index 333ce5588e..25a4226665 100644
--- a/ospf6d/ospf6_spf.c
+++ b/ospf6d/ospf6_spf.c
@@ -728,7 +728,8 @@ ospf6_spf_schedule (struct ospf6 *ospf6, unsigned int reason)
   zlog_info ("SPF: Scheduled in %ld msec", delay);
 
   ospf6->t_spf_calc =
-    thread_add_timer_msec (master, ospf6_spf_calculation_thread, ospf6, delay);
+    thread_add_timer_msec(master, ospf6_spf_calculation_thread, ospf6, delay,
+                          NULL);
 }
 
 void