diff mbox

[2/3] vringh: kill off ACCESS_ONCE()

Message ID 1479983114-17190-3-git-send-email-mark.rutland@arm.com
State Accepted
Commit 9d1b972f8a25bba01ecfc1d90d7a2fbf1923d052
Headers show

Commit Message

Mark Rutland Nov. 24, 2016, 10:25 a.m. UTC
Despite living under drivers/ vringh.c is also used as part of the userspace
virtio tools. Before we can kill off the ACCESS_ONCE()definition in the tools,
we must convert vringh.c to use {READ,WRITE}_ONCE().

This patch does so, along with the required include of <linux/compiler.h> for
the relevant definitions. The userspace tools provide their own definitions in
their own <linux/compiler.h>.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>

Cc: Jason Wang <jasowang@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
---
 drivers/vhost/vringh.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

-- 
2.7.4

Comments

Christian Borntraeger Nov. 24, 2016, 11:10 a.m. UTC | #1
On 11/24/2016 11:25 AM, Mark Rutland wrote:
> Despite living under drivers/ vringh.c is also used as part of the userspace

> virtio tools. Before we can kill off the ACCESS_ONCE()definition in the tools,

> we must convert vringh.c to use {READ,WRITE}_ONCE().

> 

> This patch does so, along with the required include of <linux/compiler.h> for

> the relevant definitions. The userspace tools provide their own definitions in

> their own <linux/compiler.h>.

> 

> Signed-off-by: Mark Rutland <mark.rutland@arm.com>

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

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

> Cc: kvm@vger.kernel.org

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

> Cc: netdev@vger.kernel.org

> Cc: virtualization@lists.linux-foundation.org

> ---

>  drivers/vhost/vringh.c | 5 +++--

>  1 file changed, 3 insertions(+), 2 deletions(-)

> 

> diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c

> index 3bb02c6..bb8971f 100644

> --- a/drivers/vhost/vringh.c

> +++ b/drivers/vhost/vringh.c

> @@ -3,6 +3,7 @@

>   *

>   * Since these may be in userspace, we use (inline) accessors.

>   */

> +#include <linux/compiler.h>

>  #include <linux/module.h>

>  #include <linux/vringh.h>

>  #include <linux/virtio_ring.h>

> @@ -820,13 +821,13 @@ EXPORT_SYMBOL(vringh_need_notify_user);

>  static inline int getu16_kern(const struct vringh *vrh,

>  			      u16 *val, const __virtio16 *p)

>  {

> -	*val = vringh16_to_cpu(vrh, ACCESS_ONCE(*p));

> +	*val = vringh16_to_cpu(vrh, READ_ONCE(*p));

>  	return 0;

>  }

> 

>  static inline int putu16_kern(const struct vringh *vrh, __virtio16 *p, u16 val)

>  {

> -	ACCESS_ONCE(*p) = cpu_to_vringh16(vrh, val);

> +	WRITE_ONCE(*p, cpu_to_vringh16(vrh, val));

>  	return 0;

>  }

> 


Makes sense

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cornelia Huck Nov. 24, 2016, 11:35 a.m. UTC | #2
On Thu, 24 Nov 2016 10:25:13 +0000
Mark Rutland <mark.rutland@arm.com> wrote:

> Despite living under drivers/ vringh.c is also used as part of the userspace

> virtio tools. Before we can kill off the ACCESS_ONCE()definition in the tools,

> we must convert vringh.c to use {READ,WRITE}_ONCE().

> 

> This patch does so, along with the required include of <linux/compiler.h> for

> the relevant definitions. The userspace tools provide their own definitions in

> their own <linux/compiler.h>.

> 

> Signed-off-by: Mark Rutland <mark.rutland@arm.com>

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

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

> Cc: kvm@vger.kernel.org

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

> Cc: netdev@vger.kernel.org

> Cc: virtualization@lists.linux-foundation.org

> ---

>  drivers/vhost/vringh.c | 5 +++--

>  1 file changed, 3 insertions(+), 2 deletions(-)


Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
diff mbox

Patch

diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
index 3bb02c6..bb8971f 100644
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -3,6 +3,7 @@ 
  *
  * Since these may be in userspace, we use (inline) accessors.
  */
+#include <linux/compiler.h>
 #include <linux/module.h>
 #include <linux/vringh.h>
 #include <linux/virtio_ring.h>
@@ -820,13 +821,13 @@  EXPORT_SYMBOL(vringh_need_notify_user);
 static inline int getu16_kern(const struct vringh *vrh,
 			      u16 *val, const __virtio16 *p)
 {
-	*val = vringh16_to_cpu(vrh, ACCESS_ONCE(*p));
+	*val = vringh16_to_cpu(vrh, READ_ONCE(*p));
 	return 0;
 }
 
 static inline int putu16_kern(const struct vringh *vrh, __virtio16 *p, u16 val)
 {
-	ACCESS_ONCE(*p) = cpu_to_vringh16(vrh, val);
+	WRITE_ONCE(*p, cpu_to_vringh16(vrh, val));
 	return 0;
 }