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

Daniel Vetter
2017-05-08T07:29:07Z

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@gmail.com>

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