Re: [PATCH v9 03/12] vfio: Rearrange functions to get vfio_group from dev

From: Alex Williamson
Date: Wed Oct 19 2016 - 13:26:26 EST


On Tue, 18 Oct 2016 02:52:03 +0530
Kirti Wankhede <kwankhede@xxxxxxxxxx> wrote:

> Rearrange functions to have common function to increment container_users.
>
> Signed-off-by: Kirti Wankhede <kwankhede@xxxxxxxxxx>
> Signed-off-by: Neo Jia <cjia@xxxxxxxxxx>
> Change-Id: I1f93262bdbab75094bc24b087b29da35ba70c4c6
> ---
> drivers/vfio/vfio.c | 57 ++++++++++++++++++++++++++++++++++-------------------
> 1 file changed, 37 insertions(+), 20 deletions(-)

Ideally these would be two separate patches, one pulling
vfio_group_get_from_dev() out of vfio_device_get_from_dev() and
replacing the existing use, the other doing the same for
vfio_group_add_container_user(). Otherwise it looks good. Thanks,

Alex

> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> index d1d70e0b011b..2e83bdf007fe 100644
> --- a/drivers/vfio/vfio.c
> +++ b/drivers/vfio/vfio.c
> @@ -480,6 +480,21 @@ static struct vfio_group *vfio_group_get_from_minor(int minor)
> return group;
> }
>
> +static struct vfio_group *vfio_group_get_from_dev(struct device *dev)
> +{
> + struct iommu_group *iommu_group;
> + struct vfio_group *group;
> +
> + iommu_group = iommu_group_get(dev);
> + if (!iommu_group)
> + return NULL;
> +
> + group = vfio_group_get_from_iommu(iommu_group);
> + iommu_group_put(iommu_group);
> +
> + return group;
> +}
> +
> /**
> * Device objects - create, release, get, put, search
> */
> @@ -811,16 +826,10 @@ EXPORT_SYMBOL_GPL(vfio_add_group_dev);
> */
> struct vfio_device *vfio_device_get_from_dev(struct device *dev)
> {
> - struct iommu_group *iommu_group;
> struct vfio_group *group;
> struct vfio_device *device;
>
> - iommu_group = iommu_group_get(dev);
> - if (!iommu_group)
> - return NULL;
> -
> - group = vfio_group_get_from_iommu(iommu_group);
> - iommu_group_put(iommu_group);
> + group = vfio_group_get_from_dev(dev);
> if (!group)
> return NULL;
>
> @@ -1376,6 +1385,23 @@ static bool vfio_group_viable(struct vfio_group *group)
> group, vfio_dev_viable) == 0);
> }
>
> +static int vfio_group_add_container_user(struct vfio_group *group)
> +{
> + if (!atomic_inc_not_zero(&group->container_users))
> + return -EINVAL;
> +
> + if (group->noiommu) {
> + atomic_dec(&group->container_users);
> + return -EPERM;
> + }
> + if (!group->container->iommu_driver || !vfio_group_viable(group)) {
> + atomic_dec(&group->container_users);
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> static const struct file_operations vfio_device_fops;
>
> static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
> @@ -1685,23 +1711,14 @@ static const struct file_operations vfio_device_fops = {
> struct vfio_group *vfio_group_get_external_user(struct file *filep)
> {
> struct vfio_group *group = filep->private_data;
> + int ret;
>
> if (filep->f_op != &vfio_group_fops)
> return ERR_PTR(-EINVAL);
>
> - if (!atomic_inc_not_zero(&group->container_users))
> - return ERR_PTR(-EINVAL);
> -
> - if (group->noiommu) {
> - atomic_dec(&group->container_users);
> - return ERR_PTR(-EPERM);
> - }
> -
> - if (!group->container->iommu_driver ||
> - !vfio_group_viable(group)) {
> - atomic_dec(&group->container_users);
> - return ERR_PTR(-EINVAL);
> - }
> + ret = vfio_group_add_container_user(group);
> + if (ret)
> + return ERR_PTR(ret);
>
> vfio_group_get(group);
>