[PATCH] m68k: introduce task_thread_info

new helper - task_thread_info(task).  On platforms that have thread_info
allocated separately (i.e.  in default case) it simply returns
task->thread_info.  m68k wants (and for good reasons) to embed its thread_info
into task_struct.  So it will (in later patch) have task_thread_info() of its
own.  For now we just add a macro for generic case and convert existing
instances of its body in core kernel to uses of new macro.  Obviously safe -
all normal architectures get the same preprocessor output they used to get.

Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/sched.c b/kernel/sched.c
index b650667..831f7e9 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1437,7 +1437,7 @@
 #endif
 #ifdef CONFIG_PREEMPT
 	/* Want to start with kernel preemption disabled. */
-	p->thread_info->preempt_count = 1;
+	task_thread_info(p)->preempt_count = 1;
 #endif
 	/*
 	 * Share the timeslice between parent and child, thus the
@@ -4410,9 +4410,9 @@
 
 	/* Set the preempt count _outside_ the spinlocks! */
 #if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL)
-	idle->thread_info->preempt_count = (idle->lock_depth >= 0);
+	task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
 #else
-	idle->thread_info->preempt_count = 0;
+	task_thread_info(idle)->preempt_count = 0;
 #endif
 }