Linux Virtualization - Aug 2016 - [PATCH] virtio-gpu: Use memdup_user() rather than duplicating its implementation

From: Markus Elfring <elfring at users.sourceforge.net>
Date: Thu, 18 Aug 2016 22:35:14 +0200

Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring at users.sourceforge.net>
---
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index c046903..512e7cd 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -152,15 +152,10 @@ static int virtio_gpu_execbuffer(struct drm_device *dev,
 	if (ret)
 		goto out_free;
 
-	buf = kmalloc(exbuf->size, GFP_KERNEL);
-	if (!buf) {
-		ret = -ENOMEM;
-		goto out_unresv;
-	}
-	if (copy_from_user(buf, (void __user *)(uintptr_t)exbuf->command,
-			   exbuf->size)) {
-		kfree(buf);
-		ret = -EFAULT;
+	buf = memdup_user((void __user *)(uintptr_t)exbuf->command,
+			  exbuf->size);
+	if (IS_ERR(buf)) {
+		ret = PTR_ERR(buf);
 		goto out_unresv;
 	}
 	virtio_gpu_cmd_submit(vgdev, buf, exbuf->size,
-- 
2.9.3

On Thu, Aug 18, 2016 at 10:42:06PM +0200, SF Markus Elfring
wrote:
> From: Markus Elfring <elfring at users.sourceforge.net>
> Date: Thu, 18 Aug 2016 22:35:14 +0200
> 
> Reuse existing functionality from memdup_user() instead of keeping
> duplicate source code.
> 
> This issue was detected by using the Coccinelle software.
> 
> Signed-off-by: Markus Elfring <elfring at users.sourceforge.net>
Applied to drm-misc.
-Daniel
> ---
>  drivers/gpu/drm/virtio/virtgpu_ioctl.c | 13 ++++---------
>  1 file changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index c046903..512e7cd 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -152,15 +152,10 @@ static int virtio_gpu_execbuffer(struct drm_device
*dev,
>  	if (ret)
>  		goto out_free;
>  
> -	buf = kmalloc(exbuf->size, GFP_KERNEL);
> -	if (!buf) {
> -		ret = -ENOMEM;
> -		goto out_unresv;
> -	}
> -	if (copy_from_user(buf, (void __user *)(uintptr_t)exbuf->command,
> -			   exbuf->size)) {
> -		kfree(buf);
> -		ret = -EFAULT;
> +	buf = memdup_user((void __user *)(uintptr_t)exbuf->command,
> +			  exbuf->size);
> +	if (IS_ERR(buf)) {
> +		ret = PTR_ERR(buf);
>  		goto out_unresv;
>  	}
>  	virtio_gpu_cmd_submit(vgdev, buf, exbuf->size,
> -- 
> 2.9.3
> 
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> dri-devel at lists.freedesktop.org
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch