From e014e9444aedc365742d533e1443b22470cc67b9 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Thu, 14 Feb 2013 14:02:13 -0700 Subject: [PATCH] vfio: Protect vfio_dev_present against device_del vfio_dev_present is meant to give us a wait_event callback so that we can block removing a device from vfio until it becomes unused. The root of this check depends on being able to get the iommu group from the device. Unfortunately if the BUS_NOTIFY_DEL_DEVICE notifier has fired then the device-group reference is no longer searchable and we fail the lookup. We don't need to go to such extents for this though. We have a reference to the device, from which we can acquire a reference to the group. We can then use the group reference to search for the device and properly block removal. Signed-off-by: Alex Williamson --- Reading git-format-patch failed