*: 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, 2 deletions

diff --git a/lib/systemd.c b/lib/systemd.c
index 4c78cf328c..e2329af93a 100644
--- a/lib/systemd.c
+++ b/lib/systemd.c
@@ -104,7 +104,7 @@ systemd_send_watchdog (struct thread *t)
 {
   systemd_send_information ("WATCHDOG=1");
 
-  thread_add_timer (systemd_master, systemd_send_watchdog, NULL, wsecs);
+  thread_add_timer(systemd_master, systemd_send_watchdog, NULL, wsecs, NULL);
 
   return 1;
 }
@@ -119,5 +119,5 @@ systemd_send_started (struct thread_master *m, int the_process)
 
   systemd_send_information ("READY=1");
   if (wsecs != 0)
-    thread_add_timer (m, systemd_send_watchdog, m, wsecs);
+    thread_add_timer(m, systemd_send_watchdog, m, wsecs, NULL);
 }