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authorAlex Williamson <alex.williamson@redhat.com>2015-02-07 01:05:07 +0300
committerAlex Williamson <alex.williamson@redhat.com>2015-02-10 22:37:47 +0300
commit13060b64b819c194909121b90b5f8dd9abb5ea4e (patch)
tree3fc90f7744d110341d191dd44fe228c70422bd69 /drivers/vfio
parent4a68810dbbb4664fe4a9ac1be4d1c0e34a9b58f5 (diff)
downloadlinux-13060b64b819c194909121b90b5f8dd9abb5ea4e.tar.xz
vfio: Add and use device request op for vfio bus drivers
When a request is made to unbind a device from a vfio bus driver, we need to wait for the device to become unused, ie. for userspace to release the device. However, we have a long standing TODO in the code to do something proactive to make that happen. To enable this, we add a request callback on the vfio bus driver struct, which is intended to signal the user through the vfio device interface to release the device. Instead of passively waiting for the device to become unused, we can now pester the user to give it up. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/vfio.c24
1 files changed, 22 insertions, 2 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 13e0f39d91e0..4cde85501444 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -710,6 +710,7 @@ void *vfio_del_group_dev(struct device *dev)
struct vfio_group *group = device->group;
void *device_data = device->device_data;
struct vfio_unbound_dev *unbound;
+ unsigned int i = 0;
/*
* The group exists so long as we have a device reference. Get
@@ -737,8 +738,27 @@ void *vfio_del_group_dev(struct device *dev)
vfio_device_put(device);
- /* TODO send a signal to encourage this to be released */
- wait_event(vfio.release_q, !vfio_dev_present(group, dev));
+ /*
+ * If the device is still present in the group after the above
+ * 'put', then it is in use and we need to request it from the
+ * bus driver. The driver may in turn need to request the
+ * device from the user. We send the request on an arbitrary
+ * interval with counter to allow the driver to take escalating
+ * measures to release the device if it has the ability to do so.
+ */
+ do {
+ device = vfio_group_get_device(group, dev);
+ if (!device)
+ break;
+
+ if (device->ops->request)
+ device->ops->request(device_data, i++);
+
+ vfio_device_put(device);
+
+ } while (wait_event_interruptible_timeout(vfio.release_q,
+ !vfio_dev_present(group, dev),
+ HZ * 10) <= 0);
vfio_group_put(group);