vfio: initialize the virqfd workqueue in VFIO generic code

Now we have finally completely decoupled virqfd from VFIO_PCI. We can
initialize it from the VFIO generic code, in order to safely use it from
multiple independent VFIO bus drivers.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
Tested-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/Makefile

@@ -1,4 +1,6 @@
-obj-$(CONFIG_VFIO) += vfio.o
+vfio_core-y := vfio.o virqfd.o
+
+obj-$(CONFIG_VFIO) += vfio_core.o
 obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
 obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
 obj-$(CONFIG_VFIO_SPAPR_EEH) += vfio_spapr_eeh.o

drivers/vfio/pci/Makefile

@@ -1,5 +1,4 @@
 
-vfio-pci-y := vfio_pci.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio_pci_config.o \
-	      ../virqfd.o
+vfio-pci-y := vfio_pci.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio_pci_config.o
 
 obj-$(CONFIG_VFIO_PCI) += vfio-pci.o

drivers/vfio/pci/vfio_pci.c

@@ -1030,7 +1030,6 @@ put_devs:
 static void __exit vfio_pci_cleanup(void)
 {
 	pci_unregister_driver(&vfio_pci_driver);
-	vfio_virqfd_exit();
 	vfio_pci_uninit_perm_bits();
 }
 
@@ -1043,11 +1042,6 @@ static int __init vfio_pci_init(void)
 	if (ret)
 		return ret;
 
-	/* Start the virqfd cleanup handler */
-	ret = vfio_virqfd_init();
-	if (ret)
-		goto out_virqfd;
-
 	/* Register and scan for devices */
 	ret = pci_register_driver(&vfio_pci_driver);
 	if (ret)
@@ -1056,8 +1050,6 @@ static int __init vfio_pci_init(void)
 	return 0;
 
 out_driver:
-	vfio_virqfd_exit();
-out_virqfd:
 	vfio_pci_uninit_perm_bits();
 	return ret;
 }

drivers/vfio/vfio.c

@@ -1553,6 +1553,11 @@ static int __init vfio_init(void)
 	if (ret)
 		goto err_cdev_add;
 
+	/* Start the virqfd cleanup handler used by some VFIO bus drivers */
+	ret = vfio_virqfd_init();
+	if (ret)
+		goto err_virqfd;
+
 	pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
 
 	/*
@@ -1565,6 +1570,8 @@ static int __init vfio_init(void)
 
 	return 0;
 
+err_virqfd:
+	cdev_del(&vfio.group_cdev);
 err_cdev_add:
 	unregister_chrdev_region(vfio.group_devt, MINORMASK);
 err_alloc_chrdev:
@@ -1579,6 +1586,7 @@ static void __exit vfio_cleanup(void)
 {
 	WARN_ON(!list_empty(&vfio.group_list));
 
+	vfio_virqfd_exit();
 	idr_destroy(&vfio.group_idr);
 	cdev_del(&vfio.group_cdev);
 	unregister_chrdev_region(vfio.group_devt, MINORMASK);