linux-kernel - Re: [PATCH -next] drm/imagination: Use memdup

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Message-ID: <74dfe952-2055-4152-90c6-ac9cc42fcad9@wanadoo.fr>
Date: Sat, 31 Aug 2024 12:48:45 +0200
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: Jinjie Ruan <ruanjinjie@...wei.com>, frank.binns@...tec.com,
 matt.coster@...tec.com, maarten.lankhorst@...ux.intel.com,
 mripard@...nel.org, tzimmermann@...e.de, airlied@...il.com, daniel@...ll.ch,
 dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH -next] drm/imagination: Use memdup_user() helper

Le 31/08/2024 à 12:30, Jinjie Ruan a écrit :
> Switching to memdup_user(), which combines kmalloc() and copy_from_user(),
> and it can simplfy code.
> 
> Signed-off-by: Jinjie Ruan <ruanjinjie@...wei.com>
> ---
>   drivers/gpu/drm/imagination/pvr_context.c | 22 +++++++---------------
>   1 file changed, 7 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/imagination/pvr_context.c b/drivers/gpu/drm/imagination/pvr_context.c
> index eded5e955cc0..e75fd50a4d9f 100644
> --- a/drivers/gpu/drm/imagination/pvr_context.c
> +++ b/drivers/gpu/drm/imagination/pvr_context.c
> @@ -69,27 +69,19 @@ process_static_context_state(struct pvr_device *pvr_dev, const struct pvr_stream
>   	void *stream;
>   	int err;
>   
> -	stream = kzalloc(stream_size, GFP_KERNEL);
> -	if (!stream)
> -		return -ENOMEM;
> -
> -	if (copy_from_user(stream, u64_to_user_ptr(stream_user_ptr), stream_size)) {
> -		err = -EFAULT;
> -		goto err_free;
> -	}
> +	stream = memdup_user(u64_to_user_ptr(stream_user_ptr), stream_size);
> +	if (IS_ERR(stream))
> +		return PTR_ERR(stream);
>   
>   	err = pvr_stream_process(pvr_dev, cmd_defs, stream, stream_size, dest);
> -	if (err)
> -		goto err_free;
> +	if (err) {
> +		kfree(stream);
> +		return err;
> +	}
>   
>   	kfree(stream);
>   
>   	return 0;
> -
> -err_free:
> -	kfree(stream);
> -
> -	return err;
>   }

It could also be:
  	err = pvr_stream_process(...);

  	kfree(stream);

  	return err;

as you did for drivers/gpu/drm/imagination/pvr_job.c.

CJ

>   
>   static int init_render_fw_objs(struct pvr_context *ctx,