Linux Virtualization - Apr 2019 - [PATCH] drm/virtio: move drm_connector_update_edid_property() call

drm_connector_update_edid_property can sleep, we must not
call it while holding a spinlock.  Move the callsize.

Reported-by: Max Filippov <jcmvbkbc at gmail.com>
Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
---
 drivers/gpu/drm/virtio/virtgpu_vq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c
b/drivers/gpu/drm/virtio/virtgpu_vq.c
index e62fe24b1a2e..5bb0f0a084e9 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -619,11 +619,11 @@ static void virtio_gpu_cmd_get_edid_cb(struct
virtio_gpu_device *vgdev,
 	output = vgdev->outputs + scanout;
 
 	new_edid = drm_do_get_edid(&output->conn, virtio_get_edid_block, resp);
+	drm_connector_update_edid_property(&output->conn, new_edid);
 
 	spin_lock(&vgdev->display_info_lock);
 	old_edid = output->edid;
 	output->edid = new_edid;
-	drm_connector_update_edid_property(&output->conn, output->edid);
 	spin_unlock(&vgdev->display_info_lock);
 
 	kfree(old_edid);
-- 
2.18.1

On Thu, Apr 4, 2019 at 9:46 PM Gerd Hoffmann <kraxel at redhat.com>
wrote:
>
> drm_connector_update_edid_property can sleep, we must not
> call it while holding a spinlock.  Move the callsize.
>
> Reported-by: Max Filippov <jcmvbkbc at gmail.com>
> Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
> ---
>  drivers/gpu/drm/virtio/virtgpu_vq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
This change fixes the warning for me, thanks!
Tested-by: Max Filippov <jcmvbkbc at gmail.com>

-- 
Thanks.
-- Max

On Fri,  5 Apr 2019 06:46:02 +0200
Gerd Hoffmann <kraxel at redhat.com> wrote:
> drm_connector_update_edid_property can sleep, we must not
> call it while holding a spinlock.  Move the callsize.
s/callsize/callsite/
> 
> Reported-by: Max Filippov <jcmvbkbc at gmail.com>
> Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
> ---
>  drivers/gpu/drm/virtio/virtgpu_vq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c
b/drivers/gpu/drm/virtio/virtgpu_vq.c
> index e62fe24b1a2e..5bb0f0a084e9 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_vq.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
> @@ -619,11 +619,11 @@ static void virtio_gpu_cmd_get_edid_cb(struct
virtio_gpu_device *vgdev,
>  	output = vgdev->outputs + scanout;
>  
>  	new_edid = drm_do_get_edid(&output->conn, virtio_get_edid_block,
resp);
> +	drm_connector_update_edid_property(&output->conn, new_edid);
>  
>  	spin_lock(&vgdev->display_info_lock);
>  	old_edid = output->edid;
>  	output->edid = new_edid;
> -	drm_connector_update_edid_property(&output->conn,
output->edid);
>  	spin_unlock(&vgdev->display_info_lock);
>  
>  	kfree(old_edid);
This gets rid of the sleeping while atomic traces I've been seeing with
an s390x guest (both virtio-gpu-pci and virtio-gpu-ccw).

Tested-by: Cornelia Huck <cohuck at redhat.com>

I have also looked at the code a bit, but don't feel confident enough
to give an R-b.

Acked-by: Cornelia Huck <cohuck at redhat.com>

On Wed, Jun 26, 2019 at 09:51:46AM +0200, Cornelia Huck
wrote:
> On Fri,  5 Apr 2019 06:46:02 +0200
> Gerd Hoffmann <kraxel at redhat.com> wrote:
> 
> > drm_connector_update_edid_property can sleep, we must not
> > call it while holding a spinlock.  Move the callsize.
> 
> s/callsize/callsite/
Fixed on commit.
> This gets rid of the sleeping while atomic traces I've been seeing with
> an s390x guest (both virtio-gpu-pci and virtio-gpu-ccw).
> 
> Tested-by: Cornelia Huck <cohuck at redhat.com>
> 
> I have also looked at the code a bit, but don't feel confident enough
> to give an R-b.
> 
> Acked-by: Cornelia Huck <cohuck at redhat.com>
Thanks.  Pushed to drm-misc-fixes.

cheers,
  Gerd