*: 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, 5 insertions, 4 deletions

diff --git a/ldpd/accept.c b/ldpd/accept.c
index 4cb461b90..5b1dacc30 100644
--- a/ldpd/accept.c
+++ b/ldpd/accept.c
@@ -58,7 +58,7 @@ accept_add(int fd, int (*cb)(struct thread *), void *arg)
 	av->arg = arg;
 	LIST_INSERT_HEAD(&accept_queue.queue, av, entry);
 
-	av->ev = thread_add_read(master, accept_cb, av, av->fd);
+	av->ev = thread_add_read(master, accept_cb, av, av->fd, NULL);
 
 	log_debug("%s: accepting on fd %d", __func__, fd);
 
@@ -85,7 +85,8 @@ accept_pause(void)
 {
 	log_debug(__func__);
 	accept_unarm();
-	accept_queue.evt = thread_add_timer(master, accept_timeout, NULL, 1);
+	accept_queue.evt = thread_add_timer(master, accept_timeout, NULL, 1,
+					    NULL);
 }
 
 void
@@ -103,7 +104,7 @@ accept_arm(void)
 {
 	struct accept_ev	*av;
 	LIST_FOREACH(av, &accept_queue.queue, entry)
-		av->ev = thread_add_read(master, accept_cb, av, av->fd);
+		av->ev = thread_add_read(master, accept_cb, av, av->fd, NULL);
 }
 
 static void
@@ -118,7 +119,7 @@ static int
 accept_cb(struct thread *thread)
 {
 	struct accept_ev	*av = THREAD_ARG(thread);
-	av->ev = thread_add_read(master, accept_cb, av, av->fd);
+	av->ev = thread_add_read(master, accept_cb, av, av->fd, NULL);
 	av->accept_cb(thread);
 
 	return (0);