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path: root/drivers/vfio/mdev/mdev_core.c
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Diffstat (limited to 'drivers/vfio/mdev/mdev_core.c')
-rw-r--r--drivers/vfio/mdev/mdev_core.c22
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);