linux-kernel - Re: [PATCH v15 09/19] drm/etnaviv: Add constructor and destructor for the etnaviv_drm

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Message-ID: <8a517e50ae08ee777a9b3465167d7ac4721e6f9f.camel@pengutronix.de>
Date: Tue, 01 Oct 2024 16:07:39 +0200
From: Lucas Stach <l.stach@...gutronix.de>
To: Sui Jingfeng <sui.jingfeng@...ux.dev>
Cc: Christian Gmeiner <christian.gmeiner@...il.com>, Russell King
	 <linux+etnaviv@...linux.org.uk>, dri-devel@...ts.freedesktop.org, 
	etnaviv@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v15 09/19] drm/etnaviv: Add constructor and destructor
 for the etnaviv_drm_private structure

Am Sonntag, dem 08.09.2024 um 17:43 +0800 schrieb Sui Jingfeng:
> Because there are a lot of data members in the struct etnaviv_drm_private,
> which are intended to be shared by all GPU cores. It can be lengthy and
> daunting on error handling, the 'gem_lock' of struct etnaviv_drm_private
> just be forgeten to destroy on driver leave.
> 
As you seem to have based this patch on top of "drm/etnaviv: Fix
missing mutex_destroy()", the last part of the above sentence doesn't
match the code. Please drop.

> Switch to use the dedicated helpers introduced, etnaviv_bind() and
> etnaviv_unbind() gets simplified. Another potential benefit is that
> we could put the struct drm_device into struct etnaviv_drm_private
> in the future, which made them share the same life time.
> 
> Signed-off-by: Sui Jingfeng <sui.jingfeng@...ux.dev>
> ---
>  drivers/gpu/drm/etnaviv/etnaviv_drv.c | 73 +++++++++++++++++----------
>  1 file changed, 46 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
> index 6591e420a051..809e5db85df4 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
> @@ -41,6 +41,45 @@ static struct device_node *etnaviv_of_first_available_node(void)
>  	return NULL;
>  }
>  
> +static struct etnaviv_drm_private *etnaviv_alloc_private(struct device *dev)
> +{
> +	struct etnaviv_drm_private *priv;
> +
> +	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return ERR_PTR(-ENOMEM);
> +
> +	xa_init_flags(&priv->active_contexts, XA_FLAGS_ALLOC);
> +
> +	mutex_init(&priv->gem_lock);
> +	INIT_LIST_HEAD(&priv->gem_list);
> +	priv->num_gpus = 0;
> +	priv->shm_gfp_mask = GFP_HIGHUSER | __GFP_RETRY_MAYFAIL | __GFP_NOWARN;
> +
> +	priv->cmdbuf_suballoc = etnaviv_cmdbuf_suballoc_new(dev);
> +	if (IS_ERR(priv->cmdbuf_suballoc)) {

If this is supposed to do everything by the books, we should also
destroy the gem_lock mutex and active_contexts xarray here.

Regards,
Lucas

> +		kfree(priv);
> +		dev_err(dev, "Failed to create cmdbuf suballocator\n");
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	return priv;
> +}
> +
> +static void etnaviv_free_private(struct etnaviv_drm_private *priv)
> +{
> +	if (!priv)
> +		return;
> +
> +	etnaviv_cmdbuf_suballoc_destroy(priv->cmdbuf_suballoc);
> +
> +	xa_destroy(&priv->active_contexts);
> +
> +	mutex_destroy(&priv->gem_lock);
> +
> +	kfree(priv);
> +}
> +
>  static void load_gpu(struct drm_device *dev)
>  {
>  	struct etnaviv_drm_private *priv = dev->dev_private;
> @@ -521,35 +560,21 @@ static int etnaviv_bind(struct device *dev)
>  	if (IS_ERR(drm))
>  		return PTR_ERR(drm);
>  
> -	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> -	if (!priv) {
> -		dev_err(dev, "failed to allocate private data\n");
> -		ret = -ENOMEM;
> +	priv = etnaviv_alloc_private(dev);
> +	if (IS_ERR(priv)) {
> +		ret = PTR_ERR(priv);
>  		goto out_put;
>  	}
> +
>  	drm->dev_private = priv;
>  
>  	dma_set_max_seg_size(dev, SZ_2G);
>  
> -	xa_init_flags(&priv->active_contexts, XA_FLAGS_ALLOC);
> -
> -	mutex_init(&priv->gem_lock);
> -	INIT_LIST_HEAD(&priv->gem_list);
> -	priv->num_gpus = 0;
> -	priv->shm_gfp_mask = GFP_HIGHUSER | __GFP_RETRY_MAYFAIL | __GFP_NOWARN;
> -
> -	priv->cmdbuf_suballoc = etnaviv_cmdbuf_suballoc_new(drm->dev);
> -	if (IS_ERR(priv->cmdbuf_suballoc)) {
> -		dev_err(drm->dev, "Failed to create cmdbuf suballocator\n");
> -		ret = PTR_ERR(priv->cmdbuf_suballoc);
> -		goto out_free_priv;
> -	}
> -
>  	dev_set_drvdata(dev, drm);
>  
>  	ret = component_bind_all(dev, drm);
>  	if (ret < 0)
> -		goto out_destroy_suballoc;
> +		goto out_free_priv;
>  
>  	load_gpu(drm);
>  
> @@ -561,11 +586,8 @@ static int etnaviv_bind(struct device *dev)
>  
>  out_unbind:
>  	component_unbind_all(dev, drm);
> -out_destroy_suballoc:
> -	etnaviv_cmdbuf_suballoc_destroy(priv->cmdbuf_suballoc);
>  out_free_priv:
> -	mutex_destroy(&priv->gem_lock);
> -	kfree(priv);
> +	etnaviv_free_private(priv);
>  out_put:
>  	drm_dev_put(drm);
>  
> @@ -581,12 +603,9 @@ static void etnaviv_unbind(struct device *dev)
>  
>  	component_unbind_all(dev, drm);
>  
> -	etnaviv_cmdbuf_suballoc_destroy(priv->cmdbuf_suballoc);
> -
> -	xa_destroy(&priv->active_contexts);
> +	etnaviv_free_private(priv);
>  
>  	drm->dev_private = NULL;
> -	kfree(priv);
>  
>  	drm_dev_put(drm);
>  }