Re: [PATCH] vfio: simplify kmalloc+copy_from_user to memdup_user

From: Alex Williamson
Date: Fri Nov 09 2012 - 08:06:29 EST


On Fri, 2012-11-02 at 10:43 +0800, Fengguang Wu wrote:
> Generated by: coccinelle/api/memdup_user.cocci
>
> Acked-by: Julia Lawall <julia.lawall@xxxxxxx>
> Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
> ---
>
> drivers/vfio/pci/vfio_pci.c | 13 ++++---------
> 1 file changed, 4 insertions(+), 9 deletions(-)
>
> --- linux.orig/drivers/vfio/pci/vfio_pci.c 2012-10-23 18:21:57.118168335 +0800
> +++ linux/drivers/vfio/pci/vfio_pci.c 2012-11-02 10:39:36.101317628 +0800
> @@ -327,15 +327,10 @@ static long vfio_pci_ioctl(void *device_
> hdr.count > vfio_pci_get_irq_count(vdev, hdr.index))
> return -EINVAL;
>
> - data = kmalloc(hdr.count * size, GFP_KERNEL);
> - if (!data)
> - return -ENOMEM;
> -
> - if (copy_from_user(data, (void __user *)(arg + minsz),
> - hdr.count * size)) {
> - kfree(data);
> - return -EFAULT;
> - }
> + data = memdup_user((void __user *)(arg + minsz),
> + hdr.count * size);
> + if (IS_ERR(data))
> + return PTR_ERR(data);
> }
>
> mutex_lock(&vdev->igate);


Thanks for the patch. Looks reasonable to me. I'll add it to my next
tree for 3.8. Thanks,

Alex

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