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vfio: Delete container_q

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Now that the iommu core takes care of isolation there is no race between
driver attach and container unset. Once iommu_group_release_dma_owner()
returns the device can immediately be re-used.

Remove this mechanism.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/0-v1-a1e8791d795b+6b-vfio_container_q_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Jason Gunthorpe 2022-04-29 15:46:17 -03:00 • committed by Alex Williamson
parent c5e8c39282
commit dc15f82f53
1 changed files with 0 additions and 20 deletions
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20
drivers/vfio/vfio.c
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@ -74,7 +74,6 @@ struct vfio_group {
struct list_head vfio_next;
struct list_head container_next;
atomic_t opened;
wait_queue_head_t container_q;
enum vfio_group_type type;
unsigned int dev_counter;
struct kvm *kvm;
@ -363,7 +362,6 @@ static struct vfio_group *vfio_group_alloc(struct iommu_group *iommu_group,
refcount_set(&group->users, 1);
INIT_LIST_HEAD(&group->device_list);
mutex_init(&group->device_lock);
init_waitqueue_head(&group->container_q);
group->iommu_group = iommu_group;
/* put in vfio_group_release() */
iommu_group_ref_get(iommu_group);
@ -684,23 +682,6 @@ void vfio_unregister_group_dev(struct vfio_device *device)
group->dev_counter--;
mutex_unlock(&group->device_lock);
/*
* In order to support multiple devices per group, devices can be
* plucked from the group while other devices in the group are still
* in use. The container persists with this group and those remaining
* devices still attached. If the user creates an isolation violation
* by binding this device to another driver while the group is still in
* use, that's their fault. However, in the case of removing the last,
* or potentially the only, device in the group there can be no other
* in-use devices in the group. The user has done their due diligence
* and we should lay no claims to those devices. In order to do that,
* we need to make sure the group is detached from the container.
* Without this stall, we're potentially racing with a user process
* that may attempt to immediately bind this device to another driver.
*/
if (list_empty(&group->device_list))
wait_event(group->container_q, !group->container);
if (group->type == VFIO_NO_IOMMU || group->type == VFIO_EMULATED_IOMMU)
iommu_group_remove_device(device->dev);
@ -945,7 +926,6 @@ static void __vfio_group_unset_container(struct vfio_group *group)
iommu_group_release_dma_owner(group->iommu_group);
group->container = NULL;
wake_up(&group->container_q);
list_del(&group->container_next);
/* Detaching the last group deprivileges a container, remove iommu */