fork: Move thread info gfp flags to header

These flags can be useful for extra allocations outside of the core
code.

Add __GFP_NOTRACK to them, so the archs which have kmemcheck do
not have to provide extra allocators just for that reason.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20120505150141.428211694@linutronix.de

include/linux/thread_info.h

@@ -54,6 +54,12 @@ extern long do_no_restart_syscall(struct restart_block *parm);
 
 #ifdef __KERNEL__
 
+#ifdef CONFIG_DEBUG_STACK_USAGE
+# define THREADINFO_GFP		(GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO)
+#else
+# define THREADINFO_GFP		(GFP_KERNEL | __GFP_NOTRACK)
+#endif
+
 /*
  * flag set/clear/test wrappers
  * - pass TIF_xxxx constants to these functions

kernel/fork.c

@@ -123,12 +123,8 @@ static struct kmem_cache *task_struct_cachep;
 static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
 						  int node)
 {
-#ifdef CONFIG_DEBUG_STACK_USAGE
-	gfp_t mask = GFP_KERNEL | __GFP_ZERO;
-#else
-	gfp_t mask = GFP_KERNEL;
-#endif
-	struct page *page = alloc_pages_node(node, mask, THREAD_SIZE_ORDER);
+	struct page *page = alloc_pages_node(node, THREADINFO_GFP,
+					     THREAD_SIZE_ORDER);
 
 	return page ? page_address(page) : NULL;
 }