*: 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/zebra/kernel_socket.c b/zebra/kernel_socket.c
index 7212ed6f26..0e15153e1d 100644
--- a/zebra/kernel_socket.c
+++ b/zebra/kernel_socket.c
@@ -1282,7 +1282,7 @@ kernel_read (struct thread *thread)
       return 0;
     }
 
-  thread_add_read (zebrad.master, kernel_read, NULL, sock);
+  thread_add_read(zebrad.master, kernel_read, NULL, sock, NULL);
 
   if (IS_ZEBRA_DEBUG_KERNEL)
     rtmsg_debug (&buf.r.rtm);
@@ -1355,7 +1355,7 @@ routing_socket (struct zebra_ns *zns)
     zlog_err ("routing_socket: Can't lower privileges");
 
   /* kernel_read needs rewrite. */
-  thread_add_read (zebrad.master, kernel_read, NULL, routing_sock);
+  thread_add_read(zebrad.master, kernel_read, NULL, routing_sock, NULL);
 }
 
 /* Exported interface function.  This function simply calls