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

Message ID 1479983114-17190-4-git-send-email-mark.rutland@arm.com
State New
Headers show

Commit Message

Mark Rutland Nov. 24, 2016, 10:25 a.m.
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@arm.com>

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

-- 
2.7.4

Comments

Jason Wang Nov. 25, 2016, 2:40 a.m. | #1
On 2016年11月24日 18:25, Mark Rutland wrote:
> 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@arm.com>

> Cc: Jason Wang <jasowang@redhat.com>

> Cc: Michael S. Tsirkin <mst@redhat.com>

> Cc: linux-kernel@vger.kernel.org

> Cc: virtualization@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;							\

>   })

>   


Reviewed-by: Jason Wang <jasowang@redhat.com>

Patch

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;							\
 })