*: 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, 4 deletions

diff --git a/zebra/kernel_netlink.c b/zebra/kernel_netlink.c
index e97420321..59a280f82 100644
--- a/zebra/kernel_netlink.c
+++ b/zebra/kernel_netlink.c
@@ -283,8 +283,8 @@ kernel_read (struct thread *thread)
 {
   struct zebra_ns *zns = (struct zebra_ns *)THREAD_ARG (thread);
   netlink_parse_info (netlink_information_fetch, &zns->netlink, zns, 5, 0);
-  zns->t_netlink = thread_add_read (zebrad.master, kernel_read, zns,
-                                     zns->netlink.sock);
+  zns->t_netlink = thread_add_read(zebrad.master, kernel_read, zns,
+                                   zns->netlink.sock, NULL);
 
   return 0;
 }
@@ -813,8 +813,8 @@ kernel_init (struct zebra_ns *zns)
         netlink_recvbuf (&zns->netlink, nl_rcvbufsize);
 
       netlink_install_filter (zns->netlink.sock, zns->netlink_cmd.snl.nl_pid);
-      zns->t_netlink = thread_add_read (zebrad.master, kernel_read, zns,
-                                         zns->netlink.sock);
+      zns->t_netlink = thread_add_read(zebrad.master, kernel_read, zns,
+                                       zns->netlink.sock, NULL);
     }
 }