diff options
Diffstat (limited to 'drivers/vfio/mdev/mdev_core.c')
-rw-r--r-- | drivers/vfio/mdev/mdev_core.c | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c index 93f8caf2e5f7..58f91b3bd670 100644 --- a/drivers/vfio/mdev/mdev_core.c +++ b/drivers/vfio/mdev/mdev_core.c @@ -70,6 +70,7 @@ int mdev_register_parent(struct mdev_parent *parent, struct device *dev, parent->mdev_driver = mdev_driver; parent->types = types; parent->nr_types = nr_types; + atomic_set(&parent->available_instances, mdev_driver->max_instances); if (!mdev_bus_compat_class) { mdev_bus_compat_class = class_compat_register("mdev_bus"); @@ -115,14 +116,17 @@ EXPORT_SYMBOL(mdev_unregister_parent); static void mdev_device_release(struct device *dev) { struct mdev_device *mdev = to_mdev_device(dev); - - /* Pairs with the get in mdev_device_create() */ - kobject_put(&mdev->type->kobj); + struct mdev_parent *parent = mdev->type->parent; mutex_lock(&mdev_list_lock); list_del(&mdev->next); + if (!parent->mdev_driver->get_available) + atomic_inc(&parent->available_instances); mutex_unlock(&mdev_list_lock); + /* Pairs with the get in mdev_device_create() */ + kobject_put(&mdev->type->kobj); + dev_dbg(&mdev->dev, "MDEV: destroying\n"); kfree(mdev); } @@ -144,6 +148,18 @@ int mdev_device_create(struct mdev_type *type, const guid_t *uuid) } } + if (!drv->get_available) { + /* + * Note: that non-atomic read and dec is fine here because + * all modifications are under mdev_list_lock. + */ + if (!atomic_read(&parent->available_instances)) { + mutex_unlock(&mdev_list_lock); + return -EUSERS; + } + atomic_dec(&parent->available_instances); + } + mdev = kzalloc(sizeof(*mdev), GFP_KERNEL); if (!mdev) { mutex_unlock(&mdev_list_lock); |