[PATCH 4.9 14/62] kasan: add a prototype of task_struct to avoid warning

[Greg Kroah-Hartman]

From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

commit 5be9b730b09c45c358bbfe7f51d254e306cccc07 upstream.

Add a prototype of task_struct to fix below warning on arm64.

  In file included from arch/arm64/kernel/probes/kprobes.c:19:0:
  include/linux/kasan.h:81:132: error: 'struct task_struct' declared inside parameter list will not be visible outside of this definition or declaration [-Werror]
   static inline void kasan_unpoison_task_stack(struct task_struct *task) {}

As same as other types (kmem_cache, page, and vm_struct) this adds a
prototype of task_struct data structure on top of kasan.h.

[arnd] A related warning was fixed before, but now appears in a
different line in the same file in v4.11-rc2.  The patch from Masami
Hiramatsu still seems appropriate, so let's take his version.

Fixes: 71af2ed5eeea ("kasan, sched/headers: Remove <linux/sched.h> from <linux/kasan.h>")
Link: https://patchwork.kernel.org/patch/9569839/
Link: http://lkml.kernel.org/r/20170313141517.3397802-1-arnd@xxxxxxxx
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Acked-by: Alexander Potapenko <glider@xxxxxxxxxx>
Acked-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 include/linux/kasan.h |    1 +
 1 file changed, 1 insertion(+)

--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -7,6 +7,7 @@
 struct kmem_cache;
 struct page;
 struct vm_struct;
+struct task_struct;
 
 #ifdef CONFIG_KASAN