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From:   Jani Nikula <jani.nikula@linux.intel.com>
To:     Sui Jingfeng <suijingfeng@loongson.cn>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Alex Deucher <alexander.deucher@amd.com>,
        Christian Koenig <christian.koenig@amd.com>,
        Pan Xinhui <Xinhui.Pan@amd.com>
Cc:     amd-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] drm: Remove the deprecated drm_put_dev() function
In-Reply-To: <20230625050901.393055-1-suijingfeng@loongson.cn>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
References: <20230625050901.393055-1-suijingfeng@loongson.cn>
Date:   Mon, 26 Jun 2023 10:48:04 +0300
Message-ID: <87jzvqy897.fsf@intel.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

On Sun, 25 Jun 2023, Sui Jingfeng <suijingfeng@loongson.cn> wrote:
> As this function can be replaced with drm_dev_unregister() + drm_dev_put(),
> it is already marked as deprecated, so remove it. No functional change.
>
> Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
> ---
>  drivers/gpu/drm/drm_drv.c           | 28 ----------------------------
>  drivers/gpu/drm/drm_pci.c           |  3 ++-
>  drivers/gpu/drm/radeon/radeon_drv.c |  3 ++-
>  include/drm/drm_drv.h               |  1 -
>  4 files changed, 4 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 12687dd9e1ac..5057307fe22a 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -406,34 +406,6 @@ void drm_minor_release(struct drm_minor *minor)
>   * possibly leaving the hardware enabled.
>   */
>  
> -/**
> - * drm_put_dev - Unregister and release a DRM device
> - * @dev: DRM device
> - *
> - * Called at module unload time or when a PCI device is unplugged.
> - *
> - * Cleans up all DRM device, calling drm_lastclose().
> - *
> - * Note: Use of this function is deprecated. It will eventually go away
> - * completely.  Please use drm_dev_unregister() and drm_dev_put() explicitly
> - * instead to make sure that the device isn't userspace accessible any more
> - * while teardown is in progress, ensuring that userspace can't access an
> - * inconsistent state.

The last sentence is the crucial one. While the patch has no functional
changes, I believe the goal never was to just mechanically replace one
call with the two.

BR,
Jani.


> - */
> -void drm_put_dev(struct drm_device *dev)
> -{
> -	DRM_DEBUG("\n");
> -
> -	if (!dev) {
> -		DRM_ERROR("cleanup called no dev\n");
> -		return;
> -	}
> -
> -	drm_dev_unregister(dev);
> -	drm_dev_put(dev);
> -}
> -EXPORT_SYMBOL(drm_put_dev);
> -
>  /**
>   * drm_dev_enter - Enter device critical section
>   * @dev: DRM device
> diff --git a/drivers/gpu/drm/drm_pci.c b/drivers/gpu/drm/drm_pci.c
> index 39d35fc3a43b..b3a68a92eaa6 100644
> --- a/drivers/gpu/drm/drm_pci.c
> +++ b/drivers/gpu/drm/drm_pci.c
> @@ -257,7 +257,8 @@ void drm_legacy_pci_exit(const struct drm_driver *driver,
>  					 legacy_dev_list) {
>  			if (dev->driver == driver) {
>  				list_del(&dev->legacy_dev_list);
> -				drm_put_dev(dev);
> +				drm_dev_unregister(dev);
> +				drm_dev_put(dev);
>  			}
>  		}
>  		mutex_unlock(&legacy_dev_list_lock);
> diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
> index e4374814f0ef..a4955ae10659 100644
> --- a/drivers/gpu/drm/radeon/radeon_drv.c
> +++ b/drivers/gpu/drm/radeon/radeon_drv.c
> @@ -357,7 +357,8 @@ radeon_pci_remove(struct pci_dev *pdev)
>  {
>  	struct drm_device *dev = pci_get_drvdata(pdev);
>  
> -	drm_put_dev(dev);
> +	drm_dev_unregister(dev);
> +	drm_dev_put(dev);
>  }
>  
>  static void
> diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
> index 89e2706cac56..289c97b12e82 100644
> --- a/include/drm/drm_drv.h
> +++ b/include/drm/drm_drv.h
> @@ -511,7 +511,6 @@ void drm_dev_unregister(struct drm_device *dev);
>  
>  void drm_dev_get(struct drm_device *dev);
>  void drm_dev_put(struct drm_device *dev);
> -void drm_put_dev(struct drm_device *dev);
>  bool drm_dev_enter(struct drm_device *dev, int *idx);
>  void drm_dev_exit(int idx);
>  void drm_dev_unplug(struct drm_device *dev);

-- 
Jani Nikula, Intel Open Source Graphics Center