*: 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, 3 insertions, 4 deletions

diff --git a/bgpd/bgp_damp.c b/bgpd/bgp_damp.c
index 168dbd012..333f58061 100644
--- a/bgpd/bgp_damp.c
+++ b/bgpd/bgp_damp.c
@@ -117,7 +117,7 @@ bgp_reuse_timer (struct thread *t)
     
   damp->t_reuse = NULL;
   damp->t_reuse =
-    thread_add_timer (bm->master, bgp_reuse_timer, NULL, DELTA_REUSE);
+    thread_add_timer(bm->master, bgp_reuse_timer, NULL, DELTA_REUSE, NULL);
 
   t_now = bgp_clock ();
 
@@ -447,9 +447,8 @@ bgp_damp_enable (struct bgp *bgp, afi_t afi, safi_t safi, time_t half,
   bgp_damp_parameter_set (half, reuse, suppress, max);
 
   /* Register reuse timer.  */
-  if (! damp->t_reuse)
-    damp->t_reuse = 
-      thread_add_timer (bm->master, bgp_reuse_timer, NULL, DELTA_REUSE);
+  thread_add_timer(bm->master, bgp_reuse_timer, NULL, DELTA_REUSE,
+                   &damp->t_reuse);
 
   return 0;
 }