linux-kernel - Re: [PATCH 3/3] virtgpu: deallocate capsets on device deinit

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Message-ID: <4si3wc7jhfcyukrepw3wi6zmylqf7b5ilnlxfpbbexcijcvlnz@3r2zcpxne275>
Date: Tue, 10 Jun 2025 15:34:13 +0200
From: Stefano Garzarella <sgarzare@...hat.com>
To: Dmitry Osipenko <dmitry.osipenko@...labora.com>
Cc: Manos Pitsidianakis <manos.pitsidianakis@...aro.org>, 
	David Airlie <airlied@...hat.com>, Gerd Hoffmann <kraxel@...hat.com>, 
	Gurchetan Singh <gurchetansingh@...omium.org>, Chia-I Wu <olvaffe@...il.com>, 
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>, 
	Thomas Zimmermann <tzimmermann@...e.de>, Simona Vetter <simona@...ll.ch>, 
	Alex Bennée <alex.bennee@...aro.org>, Viresh Kumar <viresh.kumar@...aro.org>, 
	dri-devel@...ts.freedesktop.org, virtualization@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] virtgpu: deallocate capsets on device deinit

On Mon, May 05, 2025 at 07:22:35PM +0300, Dmitry Osipenko wrote:
>On 5/5/25 18:58, Dmitry Osipenko wrote:
>> On 5/5/25 11:59, Manos Pitsidianakis wrote:
>>> diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
>>> index 7b3c4d314f8eee692e2842a7056d6dc64936fc2f..a8b751179332b9ec2fbba1392a6ee0e638a5192e 100644
>>> --- a/drivers/gpu/drm/virtio/virtgpu_kms.c
>>> +++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
>>> @@ -286,6 +286,10 @@ void virtio_gpu_deinit(struct drm_device *dev)
>>>  	flush_work(&vgdev->cursorq.dequeue_work);
>>>  	flush_work(&vgdev->config_changed_work);
>>>  	virtio_reset_device(vgdev->vdev);
>>> +	spin_lock(&vgdev->display_info_lock);
>>> +	drmm_kfree(dev, vgdev->capsets);
>>> +	vgdev->capsets = NULL;
>>> +	spin_unlock(&vgdev->display_info_lock);
>>
>> Isn't this lock superfluous?
>
>Wait a minute, vgdev->capsets is allocated using drmm, hence it's
>auto-freed when DRM device is freed. This patch shouldn't be needed.

Yep, good point. I mean the patch is not wrong, but I think we can avoid 
it.

Thanks,
Stefano