[PATCH] vfio: Remove vfio_group dev_counter

From: Jason Gunthorpe <jgg@nvidia.com>
To: Alex Williamson <alex.williamson@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>,
	kvm@vger.kernel.org
Subject: [PATCH] vfio: Remove vfio_group dev_counter
Date: Mon, 15 Aug 2022 13:50:17 -0300	[thread overview]
Message-ID: <0-v1-efa4029ed93d+22-vfio_dev_counter_jgg@nvidia.com> (raw)

This counts the number of devices attached to a vfio_group, ie the number
of items in the group->device_list.

It is only read in vfio_pin_pages(), however that function already does
vfio_assert_device_open(). Given an opened device has to already be
properly setup with a group, this test and variable are redundant. Remove
it.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/vfio/vfio_main.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 7cb56c382c97a2..76a73890d853e6 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -74,7 +74,6 @@ struct vfio_group {
 	struct list_head		vfio_next;
 	struct list_head		container_next;
 	enum vfio_group_type		type;
-	unsigned int			dev_counter;
 	struct rw_semaphore		group_rwsem;
 	struct kvm			*kvm;
 	struct file			*opened_file;
@@ -608,7 +607,6 @@ static int __vfio_register_dev(struct vfio_device *device,
 
 	mutex_lock(&group->device_lock);
 	list_add(&device->group_next, &group->device_list);
-	group->dev_counter++;
 	mutex_unlock(&group->device_lock);
 
 	return 0;
@@ -696,7 +694,6 @@ void vfio_unregister_group_dev(struct vfio_device *device)
 
 	mutex_lock(&group->device_lock);
 	list_del(&device->group_next);
-	group->dev_counter--;
 	mutex_unlock(&group->device_lock);
 
 	if (group->type == VFIO_NO_IOMMU || group->type == VFIO_EMULATED_IOMMU)
@@ -1961,9 +1958,6 @@ int vfio_pin_pages(struct vfio_device *device, dma_addr_t iova,
 	if (npage > VFIO_PIN_PAGES_MAX_ENTRIES)
 		return -E2BIG;
 
-	if (group->dev_counter > 1)
-		return -EINVAL;
-
 	/* group->container cannot change while a vfio device is open */
 	container = group->container;
 	driver = container->iommu_driver;

base-commit: 568035b01cfb107af8d2e4bd2fb9aea22cf5b868
-- 
2.37.2

