> From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> Sent: Monday, February 13, 2023 11:14 PM
>
> for counting the devices that are opened via the cdev path. This count
> is increased and decreased by the cdev path. The group path checks it
> to achieve exclusion with the cdev path. With this, only one path (group
> path or cdev path) will claim DMA ownership. This avoids scenarios in
> which devices within the same group may be opened via different paths.
please move vfio_device_claim/release_group() from patch 14 into
this patch to make the exclusiveness part complete.
>
> Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
> ---
> drivers/vfio/group.c | 5 +++++
> drivers/vfio/vfio.h | 1 +
> 2 files changed, 6 insertions(+)
>
> diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c
> index 9f3f6f0e4942..f3f5f4589cdd 100644
> --- a/drivers/vfio/group.c
> +++ b/drivers/vfio/group.c
> @@ -403,6 +403,11 @@ static int vfio_group_fops_open(struct inode *inode,
> struct file *filep)
> goto out_unlock;
> }
>
> + if (group->cdev_device_open_cnt) {
> + ret = -EBUSY;
> + goto out_unlock;
> + }
> +
> /*
> * Do we need multiple instances of the group open? Seems not.
> */
> diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
> index 6f063e31d08a..7a77fb12bd2c 100644
> --- a/drivers/vfio/vfio.h
> +++ b/drivers/vfio/vfio.h
> @@ -84,6 +84,7 @@ struct vfio_group {
> struct blocking_notifier_head notifier;
> struct iommufd_ctx *iommufd;
> spinlock_t kvm_ref_lock;
> + unsigned int cdev_device_open_cnt;
> };
>
> int vfio_device_set_group(struct vfio_device *device,
> --
> 2.34.1
