diff options
| -rw-r--r-- | drivers/vfio/vfio.c | 79 |
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) { |