[PATCH 3/3] tools/virtio: use {READ,WRITE}_ONCE() in uaccess.h

Mark Rutland
Thu, 24 Nov 2016 10:25:14 -0000

As a step towards killing off ACCESS_ONCE, use {READ,WRITE}_ONCE() for the
virtio tools uaccess primitives, pulling these in from <linux/compiler.h>.

With this done, we can kill off the now-unused ACCESS_ONCE() definition.

Signed-off-by: Mark Rutland <mark.rutland at arm.com>
Cc: Jason Wang <jasowang at redhat.com>
Cc: Michael S. Tsirkin <mst at redhat.com>
Cc: linux-kernel at vger.kernel.org
Cc: virtualization at lists.linux-foundation.org
---
 tools/virtio/linux/uaccess.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/virtio/linux/uaccess.h b/tools/virtio/linux/uaccess.h
index 0a578fe..fa05d01 100644
--- a/tools/virtio/linux/uaccess.h
+++ b/tools/virtio/linux/uaccess.h
@@ -1,8 +1,9 @@
 #ifndef UACCESS_H
 #define UACCESS_H
-extern void *__user_addr_min, *__user_addr_max;

-#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
+#include <linux/compiler.h>
+
+extern void *__user_addr_min, *__user_addr_max;

 static inline void __chk_user_ptr(const volatile void *p, size_t size)
 {
@@ -13,7 +14,7 @@ static inline void __chk_user_ptr(const volatile void *p,
size_t size)
 ({								\
 	typeof(ptr) __pu_ptr = (ptr);				\
 	__chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr));		\
-	ACCESS_ONCE(*(__pu_ptr)) = x;				\
+	WRITE_ONCE(*(__pu_ptr), x);				\
 	0;							\
 })

@@ -21,7 +22,7 @@ static inline void __chk_user_ptr(const volatile void *p,
size_t size)
 ({								\
 	typeof(ptr) __pu_ptr = (ptr);				\
 	__chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr));		\
-	x = ACCESS_ONCE(*(__pu_ptr));				\
+	x = READ_ONCE(*(__pu_ptr));				\
 	0;							\
 })

--
2.7.4