Re: [PATCH] vhost: silence an unused-variable warning

[Michael S. Tsirkin]

On Fri, Mar 08, 2019 at 03:17:26PM -0800, David Miller wrote:
> From: Arnd Bergmann 
> Date: Wed,  6 Mar 2019 12:05:49 +0100
> 
> > On some architectures, the MMU can be disabled, leading to access_ok()
> > becoming an empty macro that does not evaluate its size argument,
> > which in turn produces an unused-variable warning:
> > 
> > drivers/vhost/vhost.c:1191:9: error: unused variable 's' 
> > [-Werror,-Wunused-variable]
> > size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
> > 
> > Mark the variable as __maybe_unused to shut up that warning.
> > 
> > Signed-off-by: Arnd Bergmann 
> 
> I'll apply this, thanks Arnd.

I queued this for next linux already and it's been in linux-next
for a while. Sorry that I didn't reply, will try to remember to do it
next time.

Re: [PATCH] vhost: silence an unused-variable warning

[David Miller]

From: Arnd Bergmann 
Date: Wed,  6 Mar 2019 12:05:49 +0100

> On some architectures, the MMU can be disabled, leading to access_ok()
> becoming an empty macro that does not evaluate its size argument,
> which in turn produces an unused-variable warning:
> 
> drivers/vhost/vhost.c:1191:9: error: unused variable 's' 
> [-Werror,-Wunused-variable]
> size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
> 
> Mark the variable as __maybe_unused to shut up that warning.
> 
> Signed-off-by: Arnd Bergmann 

I'll apply this, thanks Arnd.

Re: [PATCH] vhost: silence an unused-variable warning

[Jason Wang]

On 2019/3/6 下午7:05, Arnd Bergmann wrote:

On some architectures, the MMU can be disabled, leading to access_ok()
becoming an empty macro that does not evaluate its size argument,
which in turn produces an unused-variable warning:

drivers/vhost/vhost.c:1191:9: error: unused variable 's' 
[-Werror,-Wunused-variable]
 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;

Mark the variable as __maybe_unused to shut up that warning.

Signed-off-by: Arnd Bergmann 
---
  drivers/vhost/vhost.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index a2e5dc7716e2..5ace833de746 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1188,7 +1188,7 @@ static bool vq_access_ok(struct vhost_virtqueue *vq, 
unsigned int num,
 struct vring_used __user *used)
  
  {

-   size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
+   size_t s __maybe_unused = vhost_has_feature(vq, 
VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
  
  	return access_ok(desc, num * sizeof *desc) &&

   access_ok(avail,



Acked-by: Jason Wang 

[PATCH] vhost: silence an unused-variable warning

[Arnd Bergmann]

On some architectures, the MMU can be disabled, leading to access_ok()
becoming an empty macro that does not evaluate its size argument,
which in turn produces an unused-variable warning:

drivers/vhost/vhost.c:1191:9: error: unused variable 's' 
[-Werror,-Wunused-variable]
size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;

Mark the variable as __maybe_unused to shut up that warning.

Signed-off-by: Arnd Bergmann 
---
 drivers/vhost/vhost.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index a2e5dc7716e2..5ace833de746 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1188,7 +1188,7 @@ static bool vq_access_ok(struct vhost_virtqueue *vq, 
unsigned int num,
 struct vring_used __user *used)
 
 {
-   size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
+   size_t s __maybe_unused = vhost_has_feature(vq, 
VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
 
return access_ok(desc, num * sizeof *desc) &&
   access_ok(avail,
-- 
2.20.0