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-rw-r--r--drivers/vfio/vfio.c79
1 files changed, 25 insertions, 54 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 15d8e678e556..32660e8a69ae 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -46,7 +46,6 @@ static struct vfio {
struct mutex group_lock;
struct cdev group_cdev;
dev_t group_devt;
- wait_queue_head_t release_q;
} vfio;
struct vfio_iommu_driver {
@@ -91,7 +90,8 @@ struct vfio_group {
};
struct vfio_device {
- struct kref kref;
+ refcount_t refcount;
+ struct completion comp;
struct device *dev;
const struct vfio_device_ops *ops;
struct vfio_group *group;
@@ -544,7 +544,8 @@ struct vfio_device *vfio_group_create_device(struct vfio_group *group,
if (!device)
return ERR_PTR(-ENOMEM);
- kref_init(&device->kref);
+ refcount_set(&device->refcount, 1);
+ init_completion(&device->comp);
device->dev = dev;
/* Our reference on group is moved to the device */
device->group = group;
@@ -560,35 +561,17 @@ struct vfio_device *vfio_group_create_device(struct vfio_group *group,
return device;
}
-static void vfio_device_release(struct kref *kref)
-{
- struct vfio_device *device = container_of(kref,
- struct vfio_device, kref);
- struct vfio_group *group = device->group;
-
- list_del(&device->group_next);
- group->dev_counter--;
- mutex_unlock(&group->device_lock);
-
- dev_set_drvdata(device->dev, NULL);
-
- kfree(device);
-
- /* vfio_del_group_dev may be waiting for this device */
- wake_up(&vfio.release_q);
-}
-
/* Device reference always implies a group reference */
void vfio_device_put(struct vfio_device *device)
{
- struct vfio_group *group = device->group;
- kref_put_mutex(&device->kref, vfio_device_release, &group->device_lock);
+ if (refcount_dec_and_test(&device->refcount))
+ complete(&device->comp);
}
EXPORT_SYMBOL_GPL(vfio_device_put);
-static void vfio_device_get(struct vfio_device *device)
+static bool vfio_device_try_get(struct vfio_device *device)
{
- kref_get(&device->kref);
+ return refcount_inc_not_zero(&device->refcount);
}
static struct vfio_device *vfio_group_get_device(struct vfio_group *group,
@@ -598,8 +581,7 @@ static struct vfio_device *vfio_group_get_device(struct vfio_group *group,
mutex_lock(&group->device_lock);
list_for_each_entry(device, &group->device_list, group_next) {
- if (device->dev == dev) {
- vfio_device_get(device);
+ if (device->dev == dev && vfio_device_try_get(device)) {
mutex_unlock(&group->device_lock);
return device;
}
@@ -883,9 +865,8 @@ static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group,
ret = !strcmp(dev_name(it->dev), buf);
}
- if (ret) {
+ if (ret && vfio_device_try_get(it)) {
device = it;
- vfio_device_get(device);
break;
}
}
@@ -908,13 +889,13 @@ EXPORT_SYMBOL_GPL(vfio_device_data);
* removed. Open file descriptors for the device... */
void *vfio_del_group_dev(struct device *dev)
{
- DEFINE_WAIT_FUNC(wait, woken_wake_function);
struct vfio_device *device = dev_get_drvdata(dev);
struct vfio_group *group = device->group;
void *device_data = device->device_data;
struct vfio_unbound_dev *unbound;
unsigned int i = 0;
bool interrupted = false;
+ long rc;
/*
* When the device is removed from the group, the group suddenly
@@ -935,32 +916,18 @@ void *vfio_del_group_dev(struct device *dev)
WARN_ON(!unbound);
vfio_device_put(device);
-
- /*
- * 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.
- */
- add_wait_queue(&vfio.release_q, &wait);
-
- do {
- device = vfio_group_get_device(group, dev);
- if (!device)
- break;
-
+ rc = try_wait_for_completion(&device->comp);
+ while (rc <= 0) {
if (device->ops->request)
device->ops->request(device_data, i++);
- vfio_device_put(device);
-
if (interrupted) {
- wait_woken(&wait, TASK_UNINTERRUPTIBLE, HZ * 10);
+ rc = wait_for_completion_timeout(&device->comp,
+ HZ * 10);
} else {
- wait_woken(&wait, TASK_INTERRUPTIBLE, HZ * 10);
- if (signal_pending(current)) {
+ rc = wait_for_completion_interruptible_timeout(
+ &device->comp, HZ * 10);
+ if (rc < 0) {
interrupted = true;
dev_warn(dev,
"Device is currently in use, task"
@@ -969,10 +936,13 @@ void *vfio_del_group_dev(struct device *dev)
current->comm, task_pid_nr(current));
}
}
+ }
- } while (1);
+ mutex_lock(&group->device_lock);
+ list_del(&device->group_next);
+ group->dev_counter--;
+ mutex_unlock(&group->device_lock);
- remove_wait_queue(&vfio.release_q, &wait);
/*
* In order to support multiple devices per group, devices can be
* plucked from the group while other devices in the group are still
@@ -992,6 +962,8 @@ void *vfio_del_group_dev(struct device *dev)
/* Matches the get in vfio_group_create_device() */
vfio_group_put(group);
+ dev_set_drvdata(dev, NULL);
+ kfree(device);
return device_data;
}
@@ -2362,7 +2334,6 @@ static int __init vfio_init(void)
mutex_init(&vfio.iommu_drivers_lock);
INIT_LIST_HEAD(&vfio.group_list);
INIT_LIST_HEAD(&vfio.iommu_drivers_list);
- init_waitqueue_head(&vfio.release_q);
ret = misc_register(&vfio_dev);
if (ret) {