*: 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, 6 insertions, 9 deletions

diff --git a/lib/wheel.c b/lib/wheel.c
index fe53dea29..9bcb1b874 100644
--- a/lib/wheel.c
+++ b/lib/wheel.c
@@ -60,9 +60,8 @@ wheel_timer_thread (struct thread *t)
     slots_to_skip++;
 
   wheel->slots_to_skip = slots_to_skip;
-  THREAD_TIMER_MSEC_ON (wheel->master, wheel->timer,
-			wheel_timer_thread, wheel,
-			wheel->nexttime * slots_to_skip);
+  thread_add_timer_msec(wheel->master, wheel_timer_thread, wheel,
+                        wheel->nexttime * slots_to_skip, &wheel->timer);
 
   return 0;
 }
@@ -91,9 +90,8 @@ wheel_init (struct thread_master *master, int period, size_t slots,
   for (i = 0; i < slots; i++)
     wheel->wheel_slot_lists[i] = list_new ();
 
-  THREAD_TIMER_MSEC_ON (wheel->master, wheel->timer,
-			wheel_timer_thread, wheel,
-			wheel->nexttime);
+  thread_add_timer_msec(wheel->master, wheel_timer_thread, wheel,
+                        wheel->nexttime, &wheel->timer);
 
   return wheel;
 }
@@ -124,9 +122,8 @@ int
 wheel_start (struct timer_wheel *wheel)
 {
   if (!wheel->timer)
-    THREAD_TIMER_MSEC_ON (wheel->master, wheel->timer,
-			  wheel_timer_thread, wheel,
-			  wheel->nexttime);
+    thread_add_timer_msec(wheel->master, wheel_timer_thread, wheel,
+                          wheel->nexttime, &wheel->timer);
 
   return 0;
 }