[Qemu-devel] Re: [PATCH 4/4] Add virtio disk identification support

[Rusty Russell]

On Thu, 25 Mar 2010 04:04:02 pm john cooper wrote:
> Return serial string to the guest application via
> ioctl driver call.

This is quite nice.  Minor nits:

> +     if (cmd == 'VBID') {
> +             void *usr_data = (void __user *)data;

void __user *usr_data;

> +             char *id_str;
> +             int err;
> +
> +             if (!(id_str = kmalloc(VIRTIO_BLK_ID_BYTES, GFP_KERNEL)))
> +                     err = -ENOMEM;
> +             else if ((err = virtblk_get_id(disk, id_str)))
> +                     ;
> +             else if (copy_to_user(usr_data, id_str, VIRTIO_BLK_ID_BYTES))
> +                     err = -EFAULT;
> +             if (id_str)
> +                     kfree(id_str);
> +             return err;
> +     }

We can't put the id_str on the stack?  Makes it even simpler :)

Cheers,
Rusty.