*: 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, 4 insertions, 3 deletions

diff --git a/pimd/pim_msdp_socket.c b/pimd/pim_msdp_socket.c
index 805e812ca..b09dd635a 100644
--- a/pimd/pim_msdp_socket.c
+++ b/pimd/pim_msdp_socket.c
@@ -70,8 +70,8 @@ pim_msdp_sock_accept(struct thread *thread)
     zlog_err ("accept_sock is negative value %d", accept_sock);
     return -1;
   }
-  listener->thread = thread_add_read(master, pim_msdp_sock_accept,
-                                     listener, accept_sock);
+  listener->thread = thread_add_read(master, pim_msdp_sock_accept, listener,
+                                     accept_sock, NULL);
 
   /* accept client connection. */
   msdp_sock = sockunion_accept(accept_sock, &su);
@@ -173,7 +173,8 @@ pim_msdp_sock_listen(void)
   /* add accept thread */
   listener->fd = sock;
   memcpy(&listener->su, &sin, socklen);
-  listener->thread = thread_add_read(msdp->master, pim_msdp_sock_accept, listener, sock);
+  listener->thread = thread_add_read(msdp->master, pim_msdp_sock_accept,
+                                     listener, sock, NULL);
 
   msdp->flags |= PIM_MSDPF_LISTENER;
   return 0;