Re: [Intel-gfx] [PATCH] drm/i915: use memdup_user_nul

[Daniel Vetter]

On Sat, May 06, 2017 at 11:40:17PM +0800, Geliang Tang wrote:
> Use memdup_user_nul() helper instead of open-coding to simplify the
> code.
> 
> Signed-off-by: Geliang Tang <geliangtang@xxxxxxxxx>

Thx for the patch, applied to drm-intel.git.
-Daniel

> ---
>  drivers/gpu/drm/i915/i915_debugfs.c   | 13 +++----------
>  drivers/gpu/drm/i915/intel_pipe_crc.c | 13 +++----------
>  2 files changed, 6 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index d689e51..e56b636 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -3704,16 +3704,10 @@ static ssize_t i915_displayport_test_active_write(struct file *file,
>  	if (len == 0)
>  		return 0;
>  
> -	input_buffer = kmalloc(len + 1, GFP_KERNEL);
> -	if (!input_buffer)
> -		return -ENOMEM;
> +	input_buffer = memdup_user_nul(ubuf, len);
> +	if (IS_ERR(input_buffer))
> +		return PTR_ERR(input_buffer);
>  
> -	if (copy_from_user(input_buffer, ubuf, len)) {
> -		status = -EFAULT;
> -		goto out;
> -	}
> -
> -	input_buffer[len] = '\0';
>  	DRM_DEBUG_DRIVER("Copied %d bytes from user\n", (unsigned int)len);
>  
>  	drm_connector_list_iter_begin(dev, &conn_iter);
> @@ -3739,7 +3733,6 @@ static ssize_t i915_displayport_test_active_write(struct file *file,
>  		}
>  	}
>  	drm_connector_list_iter_end(&conn_iter);
> -out:
>  	kfree(input_buffer);
>  	if (status < 0)
>  		return status;
> diff --git a/drivers/gpu/drm/i915/intel_pipe_crc.c b/drivers/gpu/drm/i915/intel_pipe_crc.c
> index 206ee4f..813dd3c 100644
> --- a/drivers/gpu/drm/i915/intel_pipe_crc.c
> +++ b/drivers/gpu/drm/i915/intel_pipe_crc.c
> @@ -842,19 +842,12 @@ static ssize_t display_crc_ctl_write(struct file *file, const char __user *ubuf,
>  		return -E2BIG;
>  	}
>  
> -	tmpbuf = kmalloc(len + 1, GFP_KERNEL);
> -	if (!tmpbuf)
> -		return -ENOMEM;
> -
> -	if (copy_from_user(tmpbuf, ubuf, len)) {
> -		ret = -EFAULT;
> -		goto out;
> -	}
> -	tmpbuf[len] = '\0';
> +	tmpbuf = memdup_user_nul(ubuf, len);
> +	if (IS_ERR(tmpbuf))
> +		return PTR_ERR(tmpbuf);
>  
>  	ret = display_crc_ctl_parse(dev_priv, tmpbuf, len);
>  
> -out:
>  	kfree(tmpbuf);
>  	if (ret < 0)
>  		return ret;
> -- 
> 2.9.3
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch