Re: [PATCH 21/52] drm: Handle dev->unique with drmm_

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Daniel,

Thank you for the patch.

On Wed, Feb 19, 2020 at 11:20:51AM +0100, Daniel Vetter wrote:
> We need to add a drmm_kstrdup for this, but let's start somewhere.
> 
> This is not exactly perfect onion unwinding, but it's jsut a kfree so
> doesn't really matter at all.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
>  drivers/gpu/drm/drm_drv.c     |  5 ++---
>  drivers/gpu/drm/drm_managed.c | 16 ++++++++++++++++
>  include/drm/drm_managed.h     |  1 +
>  3 files changed, 19 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 1ee606b4a4f9..782fd5d6f8b2 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -777,7 +777,6 @@ void drm_dev_fini(struct drm_device *dev)
>  	mutex_destroy(&dev->filelist_mutex);
>  	mutex_destroy(&dev->struct_mutex);
>  	drm_legacy_destroy_members(dev);
> -	kfree(dev->unique);
>  }
>  EXPORT_SYMBOL(drm_dev_fini);
>  
> @@ -1063,8 +1062,8 @@ EXPORT_SYMBOL(drm_dev_unregister);
>   */
>  int drm_dev_set_unique(struct drm_device *dev, const char *name)
>  {
> -	kfree(dev->unique);
> -	dev->unique = kstrdup(name, GFP_KERNEL);
> +	drmm_kfree(dev, dev->unique);
> +	dev->unique = drmm_kstrdup(dev, name, GFP_KERNEL);
>  
>  	return dev->unique ? 0 : -ENOMEM;
>  }
> diff --git a/drivers/gpu/drm/drm_managed.c b/drivers/gpu/drm/drm_managed.c
> index ee7c7253af61..d8a484e19830 100644
> --- a/drivers/gpu/drm/drm_managed.c
> +++ b/drivers/gpu/drm/drm_managed.c
> @@ -147,6 +147,22 @@ void *drmm_kmalloc(struct drm_device *dev, size_t size, gfp_t gfp)
>  }
>  EXPORT_SYMBOL(drmm_kmalloc);
>  
> +char *drmm_kstrdup(struct drm_device *dev, const char *s, gfp_t gfp)

Do we need support for gfp_t other than GFP_KERNEL ? Given that the
memory will be released when the drm_device is destroyed, GFP_ATOMIC
would seem of dubious use to me, and we may want to not make it possible
to use it.

> +{
> +	size_t size;
> +	char *buf;
> +
> +	if (!s)
> +		return NULL;
> +
> +	size = strlen(s) + 1;
> +	buf = drmm_kmalloc(dev, size, gfp);
> +	if (buf)
> +		memcpy(buf, s, size);
> +	return buf;
> +}
> +EXPORT_SYMBOL_GPL(drmm_kstrdup);
> +
>  void drmm_kfree(struct drm_device *dev, void *data)
>  {
>  	struct drmres *dr = NULL, *tmp;
> diff --git a/include/drm/drm_managed.h b/include/drm/drm_managed.h
> index 75f2c8932c69..240edd395e88 100644
> --- a/include/drm/drm_managed.h
> +++ b/include/drm/drm_managed.h
> @@ -21,5 +21,6 @@ static inline void *drmm_kzalloc(struct drm_device *dev, size_t size, gfp_t gfp)
>  {
>  	return drmm_kmalloc(dev, size, gfp | __GFP_ZERO);
>  }
> +char *drmm_kstrdup(struct drm_device *dev, const char *s, gfp_t gfp);
>  
>  void drmm_kfree(struct drm_device *dev, void *data);

-- 
Regards,

Laurent Pinchart
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