[PATCH 3/3] thread_info: include <current.h> for THREAD_INFO_IN_TASK

From: Mark Rutland
Date: Wed Oct 19 2016 - 14:30:54 EST

When CONFIG_THREAD_INFO_IN_TASK is selected, the current_thread_info()
macro relies on current having been defined prior to its use. However,
not all users of current_thread_info() include <asm/current.h>, and thus
current is not guaranteed to be defined.

When CONFIG_THREAD_INFO_IN_TASK is not selected, it's possible that
get_current() / current are based upon current_thread_info(), and
<asm/current.h> includes <asm/thread_info.h>. Thus always including
<asm/current.h> would result in circular dependences on some platforms.

To ensure both cases work, this patch includes <asm/current.h>, but only
when CONFIG_THREAD_INFO_IN_TASK is selected.

Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
include/linux/thread_info.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index c75c6ab..ef1f4b0 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -12,6 +12,7 @@
#include <linux/restart_block.h>

+#include <asm/current.h>
#define current_thread_info() ((struct thread_info *)current)