Hi Peter,
Thank you for the patch.
On Tuesday, 29 August 2017 10:32:12 EEST Peter Ujfalusi wrote:
> It makes the cleanup paths a bit cleaner.
But it also goes against a proper implementation of object lifetime management
:-( In DRM driver private structures are accessible from file operations, and
must thus be reference-counted and only freed when the last userspace user
goes away. This may be after the devm_* resources are released right after the
.remove() operation is called. Using devm_kzalloc() would thus make it
impossible to properly reference-count our data structures.
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> ---
> drivers/gpu/drm/omapdrm/omap_drv.c | 19 +++++++------------
> 1 file changed, 7 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c
> b/drivers/gpu/drm/omapdrm/omap_drv.c index 9b3c36b48356..903510d8054e
> 100644
> --- a/drivers/gpu/drm/omapdrm/omap_drv.c
> +++ b/drivers/gpu/drm/omapdrm/omap_drv.c
> @@ -548,19 +548,17 @@ static int pdev_probe(struct platform_device *pdev)
> return ret;
> }
>
> + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> omap_crtc_pre_init();
>
> ret = omap_connect_dssdevs();
> if (ret)
> goto err_crtc_uninit;
>
> - /* Allocate and initialize the driver private structure. */
> - priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> - if (!priv) {
> - ret = -ENOMEM;
> - goto err_disconnect_dssdevs;
> - }
> -
> + /* Initialize the driver private structure. */
> priv->dispc_ops = dispc_get_ops();
>
> soc = soc_device_match(omapdrm_soc_devices);
> @@ -574,7 +572,7 @@ static int pdev_probe(struct platform_device *pdev)
> ddev = drm_dev_alloc(&omap_drm_driver, &pdev->dev);
> if (IS_ERR(ddev)) {
> ret = PTR_ERR(ddev);
> - goto err_free_priv;
> + goto err_destroy_wq;
> }
>
> ddev->dev_private = priv;
> @@ -624,10 +622,8 @@ static int pdev_probe(struct platform_device *pdev)
> err_free_drm_dev:
> omap_gem_deinit(ddev);
> drm_dev_unref(ddev);
> -err_free_priv:
> +err_destroy_wq:
> destroy_workqueue(priv->wq);
> - kfree(priv);
> -err_disconnect_dssdevs:
> omap_disconnect_dssdevs();
> err_crtc_uninit:
> omap_crtc_pre_uninit();
> @@ -659,7 +655,6 @@ static int pdev_remove(struct platform_device *pdev)
> drm_dev_unref(ddev);
>
> destroy_workqueue(priv->wq);
> - kfree(priv);
>
> omap_disconnect_dssdevs();
> omap_crtc_pre_uninit();
--
Regards,
Laurent Pinchart
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