[PATCH 5/9] vfio/pci: introduce vfio_pci_device structure

[Max Gurtovoy <mgurtovoy@nvidia.com>]

This structure will hold the specific attributes for the generic
vfio_pci.ko driver. It will be allocated by the vfio_pci driver that
will register the vfio subsystem using vfio_pci_core_register_device
and it will unregister the using vfio_pci_core_unregister_device. In
this way every vfio_pci future driver will be able to use this mechanism
to set vendor specific attributes in its vendor specific structure and
register to subsystem core while utilizing vfio_pci_core library.

This is a standard Linux subsystem behaviour and will also ease on
vfio_pci drivers to extend callbacks of vfio_device_ops and will be able
to use container_of mechanism as well (instead of passing void pointers
as around the stack).

Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
---
 drivers/vfio/pci/vfio_pci.c      | 31 +++++++++++++++++++++----
 drivers/vfio/pci/vfio_pci_core.c | 39 +++++++++++++-------------------
 drivers/vfio/pci/vfio_pci_core.h |  5 ++--
 3 files changed, 45 insertions(+), 30 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 447c31f4e64e..dbc0a6559914 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -19,6 +19,7 @@
 #include <linux/iommu.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/list.h>
 #include <linux/notifier.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
@@ -31,6 +32,10 @@
 #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
 #define DRIVER_DESC     "VFIO PCI - User Level meta-driver"
 
+struct vfio_pci_device {
+	struct vfio_pci_core_device	vdev;
+};
+
 static char ids[1024] __initdata;
 module_param_string(ids, ids, sizeof(ids), 0);
 MODULE_PARM_DESC(ids, "Initial PCI IDs to add to the vfio driver, format is \"vendor:device[:subvendor[:subdevice[:class[:class_mask]]]]\" and multiple comma separated entries can be specified");
@@ -139,21 +144,37 @@ static const struct vfio_device_ops vfio_pci_ops = {
 
 static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
-	struct vfio_pci_core_device *vdev;
+	struct vfio_pci_device *vpdev;
+	int ret;
 
 	if (vfio_pci_is_denylisted(pdev))
 		return -EINVAL;
 
-	vdev = vfio_create_pci_device(pdev, &vfio_pci_ops);
-	if (IS_ERR(vdev))
-		return PTR_ERR(vdev);
+	vpdev = kzalloc(sizeof(*vpdev), GFP_KERNEL);
+	if (!vpdev)
+		return -ENOMEM;
+
+	ret = vfio_pci_core_register_device(&vpdev->vdev, pdev, &vfio_pci_ops);
+	if (ret)
+		goto out_free;
 
 	return 0;
+
+out_free:
+	kfree(vpdev);
+	return ret;
 }
 
 static void vfio_pci_remove(struct pci_dev *pdev)
 {
-	vfio_destroy_pci_device(pdev);
+	struct vfio_device *vdev = dev_get_drvdata(&pdev->dev);
+	struct vfio_pci_core_device *core_vpdev = vfio_device_data(vdev);
+	struct vfio_pci_device *vpdev;
+
+	vpdev = container_of(core_vpdev, struct vfio_pci_device, vdev);
+
+	vfio_pci_core_unregister_device(core_vpdev);
+	kfree(vpdev);
 }
 
 static int vfio_pci_sriov_configure(struct pci_dev *pdev, int nr_virtfn)
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 878a3609b916..7b6be1e4646f 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1837,15 +1837,15 @@ static int vfio_pci_bus_notifier(struct notifier_block *nb,
 	return 0;
 }
 
-struct vfio_pci_core_device *vfio_create_pci_device(struct pci_dev *pdev,
+int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev,
+		struct pci_dev *pdev,
 		const struct vfio_device_ops *vfio_pci_ops)
 {
-	struct vfio_pci_core_device *vdev;
 	struct iommu_group *group;
 	int ret;
 
 	if (pdev->hdr_type != PCI_HEADER_TYPE_NORMAL)
-		return ERR_PTR(-EINVAL);
+		return -EINVAL;
 
 	/*
 	 * Prevent binding to PFs with VFs enabled, the VFs might be in use
@@ -1857,18 +1857,12 @@ struct vfio_pci_core_device *vfio_create_pci_device(struct pci_dev *pdev,
 	 */
 	if (pci_num_vf(pdev)) {
 		pci_warn(pdev, "Cannot bind to PF with SR-IOV enabled\n");
-		return ERR_PTR(-EBUSY);
+		return -EBUSY;
 	}
 
 	group = vfio_iommu_group_get(&pdev->dev);
 	if (!group)
-		return ERR_PTR(-EINVAL);
-
-	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
-	if (!vdev) {
-		ret = -ENOMEM;
-		goto out_group_put;
-	}
+		return -EINVAL;
 
 	vdev->pdev = pdev;
 	vdev->vfio_pci_ops = vfio_pci_ops;
@@ -1884,7 +1878,7 @@ struct vfio_pci_core_device *vfio_create_pci_device(struct pci_dev *pdev,
 
 	ret = vfio_add_group_dev(&pdev->dev, vfio_pci_ops, vdev);
 	if (ret)
-		goto out_free;
+		goto out_group_put;
 
 	ret = vfio_pci_reflck_attach(vdev);
 	if (ret)
@@ -1928,7 +1922,7 @@ struct vfio_pci_core_device *vfio_create_pci_device(struct pci_dev *pdev,
 		vfio_pci_set_power_state(vdev, PCI_D3hot);
 	}
 
-	return vdev;
+	return 0;
 
 out_vf_token:
 	kfree(vdev->vf_token);
@@ -1936,22 +1930,22 @@ struct vfio_pci_core_device *vfio_create_pci_device(struct pci_dev *pdev,
 	vfio_pci_reflck_put(vdev->reflck);
 out_del_group_dev:
 	vfio_del_group_dev(&pdev->dev);
-out_free:
-	kfree(vdev);
 out_group_put:
 	vfio_iommu_group_put(group, &pdev->dev);
-	return ERR_PTR(ret);
+	return ret;
 }
-EXPORT_SYMBOL_GPL(vfio_create_pci_device);
+EXPORT_SYMBOL_GPL(vfio_pci_core_register_device);
 
-void vfio_destroy_pci_device(struct pci_dev *pdev)
+void vfio_pci_core_unregister_device(struct vfio_pci_core_device *vdev)
 {
-	struct vfio_pci_core_device *vdev;
+	struct pci_dev *pdev;
+	struct vfio_pci_core_device *g_vdev;
 
+	pdev = vdev->pdev;
 	pci_disable_sriov(pdev);
 
-	vdev = vfio_del_group_dev(&pdev->dev);
-	if (!vdev)
+	g_vdev = vfio_del_group_dev(&pdev->dev);
+	if (g_vdev != vdev)
 		return;
 
 	if (vdev->vf_token) {
@@ -1973,7 +1967,6 @@ void vfio_destroy_pci_device(struct pci_dev *pdev)
 		vfio_pci_set_power_state(vdev, PCI_D0);
 
 	kfree(vdev->pm_save);
-	kfree(vdev);
 
 	if (vfio_pci_is_vga(pdev)) {
 		vga_client_register(pdev, NULL, NULL, NULL);
@@ -1982,7 +1975,7 @@ void vfio_destroy_pci_device(struct pci_dev *pdev)
 				VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM);
 	}
 }
-EXPORT_SYMBOL_GPL(vfio_destroy_pci_device);
+EXPORT_SYMBOL_GPL(vfio_pci_core_unregister_device);
 
 static pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
 		pci_channel_state_t state)
diff --git a/drivers/vfio/pci/vfio_pci_core.h b/drivers/vfio/pci/vfio_pci_core.h
index a3517a9472bd..46eb3443125b 100644
--- a/drivers/vfio/pci/vfio_pci_core.h
+++ b/drivers/vfio/pci/vfio_pci_core.h
@@ -231,9 +231,10 @@ static inline int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev,
 #endif
 
 /* Exported functions */
-struct vfio_pci_core_device *vfio_create_pci_device(struct pci_dev *pdev,
+int vfio_pci_core_register_device(struct vfio_pci_core_device *vdev,
+		struct pci_dev *pdev,
 		const struct vfio_device_ops *vfio_pci_ops);
-void vfio_destroy_pci_device(struct pci_dev *pdev);
+void vfio_pci_core_unregister_device(struct vfio_pci_core_device *vdev);
 
 long vfio_pci_core_ioctl(void *device_data, unsigned int cmd,
 		unsigned long arg);
-- 
2.25.4