*: 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, 8 insertions, 10 deletions

diff --git a/ospfd/ospf_packet.c b/ospfd/ospf_packet.c
index b7721adb3e..6b5b0e4edd 100644
--- a/ospfd/ospf_packet.c
+++ b/ospfd/ospf_packet.c
@@ -487,7 +487,7 @@ ospf_ls_req_event (struct ospf_neighbor *nbr)
       thread_cancel (nbr->t_ls_req);
       nbr->t_ls_req = NULL;
     }
-  nbr->t_ls_req = thread_add_event (master, ospf_ls_req_timer, nbr, 0);
+  nbr->t_ls_req = thread_add_event(master, ospf_ls_req_timer, nbr, 0, NULL);
 }
 
 /* Cyclic timer function.  Fist registered in ospf_nbr_new () in
@@ -852,7 +852,7 @@ ospf_write (struct thread *thread)
   /* If packets still remain in queue, call write thread. */
   if (!list_isempty (ospf->oi_write_q))
     ospf->t_write =                                              
-      thread_add_write (master, ospf_write, ospf, ospf->fd);
+      thread_add_write(master, ospf_write, ospf, ospf->fd, NULL);
 
   return 0;
 }
@@ -2772,7 +2772,7 @@ ospf_read (struct thread *thread)
   ospf = THREAD_ARG (thread);
 
   /* prepare for next packet. */
-  ospf->t_read = thread_add_read (master, ospf_read, ospf, ospf->fd);
+  ospf->t_read = thread_add_read(master, ospf_read, ospf, ospf->fd, NULL);
 
   stream_reset(ospf->ibuf);
   if (!(ibuf = ospf_recv_packet (ospf->fd, &ifp, ospf->ibuf)))
@@ -3803,7 +3803,7 @@ ospf_ls_upd_send_queue_event (struct thread *thread)
         zlog_debug ("ospf_ls_upd_send_queue: update lists not cleared,"
                    " %d nodes to try again, raising new event", again);
       oi->t_ls_upd_event = 
-        thread_add_event (master, ospf_ls_upd_send_queue_event, oi, 0);
+        thread_add_event(master, ospf_ls_upd_send_queue_event, oi, 0, NULL);
     }
 
   if (IS_DEBUG_OSPF_EVENT)
@@ -3858,9 +3858,8 @@ ospf_ls_upd_send (struct ospf_neighbor *nbr, struct list *update, int flag)
   for (ALL_LIST_ELEMENTS_RO (update, node, lsa))
     listnode_add (rn->info, ospf_lsa_lock (lsa)); /* oi->ls_upd_queue */
 
-  if (oi->t_ls_upd_event == NULL)
-    oi->t_ls_upd_event =
-      thread_add_event (master, ospf_ls_upd_send_queue_event, oi, 0);
+  thread_add_event(master, ospf_ls_upd_send_queue_event, oi, 0,
+                   &oi->t_ls_upd_event);
 }
 
 static void
@@ -3921,9 +3920,8 @@ ospf_ls_ack_send (struct ospf_neighbor *nbr, struct ospf_lsa *lsa)
   
   listnode_add (oi->ls_ack_direct.ls_ack, ospf_lsa_lock (lsa));
   
-  if (oi->t_ls_ack_direct == NULL)
-    oi->t_ls_ack_direct =
-      thread_add_event (master, ospf_ls_ack_send_event, oi, 0);
+  thread_add_event(master, ospf_ls_ack_send_event, oi, 0,
+                   &oi->t_ls_ack_direct);
 }
 
 /* Send Link State Acknowledgment delayed. */