*: 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, 4 deletions

diff --git a/zebra/irdp_interface.c b/zebra/irdp_interface.c
index 5cabe7e62f..cb0cb349de 100644
--- a/zebra/irdp_interface.c
+++ b/zebra/irdp_interface.c
@@ -259,10 +259,8 @@ irdp_if_start(struct interface *ifp, int multicast, int set_defaults)
 	       ifp->name,
 	       timer);
 
-  irdp->t_advertise = thread_add_timer(zebrad.master,
-				       irdp_send_thread,
-				       ifp,
-				       timer);
+  irdp->t_advertise = thread_add_timer(zebrad.master, irdp_send_thread, ifp,
+                                       timer, NULL);
 }
 
 static void