linux-kernel - Re: [PATCH v5 5/6] drm/qxl: properly free qxl releases

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Date:   Wed, 3 Feb 2021 15:12:01 +0100
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     Gerd Hoffmann <kraxel@...hat.com>, dri-devel@...ts.freedesktop.org
Cc:     David Airlie <airlied@...ux.ie>,
        open list <linux-kernel@...r.kernel.org>,
        "open list:DRM DRIVER FOR QXL VIRTUAL GPU" 
        <virtualization@...ts.linux-foundation.org>,
        "open list:DRM DRIVER FOR QXL VIRTUAL GPU" 
        <spice-devel@...ts.freedesktop.org>,
        Dave Airlie <airlied@...hat.com>
Subject: Re: [PATCH v5 5/6] drm/qxl: properly free qxl releases



Am 03.02.21 um 14:16 schrieb Gerd Hoffmann:
> Reorganize qxl_device_fini() a bit.
> Add missing unpin() calls.
> 
> Count releases.  Add wait queue for releases.  That way
> qxl_device_fini() can easily wait until everything is
> ready for proper shutdown.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@...hat.com>

Acked-by: Thomas Zimmermann <tzimmermann@...e.de>

> ---
>   drivers/gpu/drm/qxl/qxl_drv.h     |  2 ++
>   drivers/gpu/drm/qxl/qxl_cmd.c     |  1 +
>   drivers/gpu/drm/qxl/qxl_irq.c     |  1 +
>   drivers/gpu/drm/qxl/qxl_kms.c     | 22 ++++++++++++++++++++--
>   drivers/gpu/drm/qxl/qxl_release.c |  2 ++
>   5 files changed, 26 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/qxl/qxl_drv.h b/drivers/gpu/drm/qxl/qxl_drv.h
> index 01354b43c413..6dd57cfb2e7c 100644
> --- a/drivers/gpu/drm/qxl/qxl_drv.h
> +++ b/drivers/gpu/drm/qxl/qxl_drv.h
> @@ -214,6 +214,8 @@ struct qxl_device {
>   	spinlock_t	release_lock;
>   	struct idr	release_idr;
>   	uint32_t	release_seqno;
> +	atomic_t	release_count;
> +	wait_queue_head_t release_event;
>   	spinlock_t release_idr_lock;
>   	struct mutex	async_io_mutex;
>   	unsigned int last_sent_io_cmd;
> diff --git a/drivers/gpu/drm/qxl/qxl_cmd.c b/drivers/gpu/drm/qxl/qxl_cmd.c
> index 54e3c3a97440..7e22a81bfb36 100644
> --- a/drivers/gpu/drm/qxl/qxl_cmd.c
> +++ b/drivers/gpu/drm/qxl/qxl_cmd.c
> @@ -254,6 +254,7 @@ int qxl_garbage_collect(struct qxl_device *qdev)
>   		}
>   	}
>   
> +	wake_up_all(&qdev->release_event);
>   	DRM_DEBUG_DRIVER("%d\n", i);
>   
>   	return i;
> diff --git a/drivers/gpu/drm/qxl/qxl_irq.c b/drivers/gpu/drm/qxl/qxl_irq.c
> index ddf6588a2a38..d312322cacd1 100644
> --- a/drivers/gpu/drm/qxl/qxl_irq.c
> +++ b/drivers/gpu/drm/qxl/qxl_irq.c
> @@ -87,6 +87,7 @@ int qxl_irq_init(struct qxl_device *qdev)
>   	init_waitqueue_head(&qdev->display_event);
>   	init_waitqueue_head(&qdev->cursor_event);
>   	init_waitqueue_head(&qdev->io_cmd_event);
> +	init_waitqueue_head(&qdev->release_event);
>   	INIT_WORK(&qdev->client_monitors_config_work,
>   		  qxl_client_monitors_config_work_func);
>   	atomic_set(&qdev->irq_received, 0);
> diff --git a/drivers/gpu/drm/qxl/qxl_kms.c b/drivers/gpu/drm/qxl/qxl_kms.c
> index 4a60a52ab62e..616aea948863 100644
> --- a/drivers/gpu/drm/qxl/qxl_kms.c
> +++ b/drivers/gpu/drm/qxl/qxl_kms.c
> @@ -286,8 +286,26 @@ int qxl_device_init(struct qxl_device *qdev,
>   
>   void qxl_device_fini(struct qxl_device *qdev)
>   {
> -	qxl_bo_unref(&qdev->current_release_bo[0]);
> -	qxl_bo_unref(&qdev->current_release_bo[1]);
> +	int cur_idx;
> +
> +	for (cur_idx = 0; cur_idx < 3; cur_idx++) {
> +		if (!qdev->current_release_bo[cur_idx])
> +			continue;
> +		qxl_bo_unpin(qdev->current_release_bo[cur_idx]);
> +		qxl_bo_unref(&qdev->current_release_bo[cur_idx]);
> +		qdev->current_release_bo_offset[cur_idx] = 0;
> +		qdev->current_release_bo[cur_idx] = NULL;
> +	}
> +
> +	/*
> +	 * Ask host to release resources (+fill release ring),
> +	 * then wait for the release actually happening.
> +	 */
> +	qxl_io_notify_oom(qdev);
> +	wait_event_timeout(qdev->release_event,
> +			   atomic_read(&qdev->release_count) == 0,
> +			   HZ);
> +
>   	qxl_gem_fini(qdev);
>   	qxl_bo_fini(qdev);
>   	flush_work(&qdev->gc_work);
> diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
> index 28013fd1f8ea..43a5436853b7 100644
> --- a/drivers/gpu/drm/qxl/qxl_release.c
> +++ b/drivers/gpu/drm/qxl/qxl_release.c
> @@ -196,6 +196,7 @@ qxl_release_free(struct qxl_device *qdev,
>   		qxl_release_free_list(release);
>   		kfree(release);
>   	}
> +	atomic_dec(&qdev->release_count);
>   }
>   
>   static int qxl_release_bo_alloc(struct qxl_device *qdev,
> @@ -344,6 +345,7 @@ int qxl_alloc_release_reserved(struct qxl_device *qdev, unsigned long size,
>   			*rbo = NULL;
>   		return idr_ret;
>   	}
> +	atomic_inc(&qdev->release_count);
>   
>   	mutex_lock(&qdev->release_mutex);
>   	if (qdev->current_release_bo_offset[cur_idx] + 1 >= releases_per_bo[cur_idx]) {
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer



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