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-rw-r--r--drivers/vfio/mdev/mdev_core.c72
-rw-r--r--drivers/vfio/mdev/mdev_private.h2
2 files changed, 56 insertions, 18 deletions
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 0bef0cae1d4b..ae23151442cb 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -102,11 +102,35 @@ static void mdev_put_parent(struct mdev_parent *parent)
kref_put(&parent->ref, mdev_release_parent);
}
+/* Caller must hold parent unreg_sem read or write lock */
+static void mdev_device_remove_common(struct mdev_device *mdev)
+{
+ struct mdev_parent *parent;
+ struct mdev_type *type;
+ int ret;
+
+ type = to_mdev_type(mdev->type_kobj);
+ mdev_remove_sysfs_files(&mdev->dev, type);
+ device_del(&mdev->dev);
+ parent = mdev->parent;
+ lockdep_assert_held(&parent->unreg_sem);
+ ret = parent->ops->remove(mdev);
+ if (ret)
+ dev_err(&mdev->dev, "Remove failed: err=%d\n", ret);
+
+ /* Balances with device_initialize() */
+ put_device(&mdev->dev);
+ mdev_put_parent(parent);
+}
+
static int mdev_device_remove_cb(struct device *dev, void *data)
{
- if (dev_is_mdev(dev))
- mdev_device_remove(dev);
+ if (dev_is_mdev(dev)) {
+ struct mdev_device *mdev;
+ mdev = to_mdev_device(dev);
+ mdev_device_remove_common(mdev);
+ }
return 0;
}
@@ -148,6 +172,7 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
}
kref_init(&parent->ref);
+ init_rwsem(&parent->unreg_sem);
parent->dev = dev;
parent->ops = ops;
@@ -206,21 +231,23 @@ void mdev_unregister_device(struct device *dev)
dev_info(dev, "MDEV: Unregistering\n");
list_del(&parent->next);
+ mutex_unlock(&parent_list_lock);
+
+ down_write(&parent->unreg_sem);
+
class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
device_for_each_child(dev, NULL, mdev_device_remove_cb);
parent_remove_sysfs_files(parent);
+ up_write(&parent->unreg_sem);
- mutex_unlock(&parent_list_lock);
mdev_put_parent(parent);
}
EXPORT_SYMBOL(mdev_unregister_device);
-static void mdev_device_release(struct device *dev)
+static void mdev_device_free(struct mdev_device *mdev)
{
- struct mdev_device *mdev = to_mdev_device(dev);
-
mutex_lock(&mdev_list_lock);
list_del(&mdev->next);
mutex_unlock(&mdev_list_lock);
@@ -229,6 +256,13 @@ static void mdev_device_release(struct device *dev)
kfree(mdev);
}
+static void mdev_device_release(struct device *dev)
+{
+ struct mdev_device *mdev = to_mdev_device(dev);
+
+ mdev_device_free(mdev);
+}
+
int mdev_device_create(struct kobject *kobj,
struct device *dev, const guid_t *uuid)
{
@@ -265,6 +299,13 @@ int mdev_device_create(struct kobject *kobj,
mdev->parent = parent;
+ /* Check if parent unregistration has started */
+ if (!down_read_trylock(&parent->unreg_sem)) {
+ mdev_device_free(mdev);
+ ret = -ENODEV;
+ goto mdev_fail;
+ }
+
device_initialize(&mdev->dev);
mdev->dev.parent = dev;
mdev->dev.bus = &mdev_bus_type;
@@ -287,6 +328,7 @@ int mdev_device_create(struct kobject *kobj,
mdev->active = true;
dev_dbg(&mdev->dev, "MDEV: created\n");
+ up_read(&parent->unreg_sem);
return 0;
@@ -295,6 +337,7 @@ sysfs_fail:
add_fail:
parent->ops->remove(mdev);
ops_create_fail:
+ up_read(&parent->unreg_sem);
put_device(&mdev->dev);
mdev_fail:
mdev_put_parent(parent);
@@ -305,8 +348,6 @@ int mdev_device_remove(struct device *dev)
{
struct mdev_device *mdev, *tmp;
struct mdev_parent *parent;
- struct mdev_type *type;
- int ret;
mdev = to_mdev_device(dev);
@@ -329,18 +370,13 @@ int mdev_device_remove(struct device *dev)
mdev->active = false;
mutex_unlock(&mdev_list_lock);
- type = to_mdev_type(mdev->type_kobj);
- mdev_remove_sysfs_files(dev, type);
- device_del(&mdev->dev);
parent = mdev->parent;
- ret = parent->ops->remove(mdev);
- if (ret)
- dev_err(&mdev->dev, "Remove failed: err=%d\n", ret);
-
- /* Balances with device_initialize() */
- put_device(&mdev->dev);
- mdev_put_parent(parent);
+ /* Check if parent unregistration has started */
+ if (!down_read_trylock(&parent->unreg_sem))
+ return -ENODEV;
+ mdev_device_remove_common(mdev);
+ up_read(&parent->unreg_sem);
return 0;
}
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
index 924ed2274941..398767526276 100644
--- a/drivers/vfio/mdev/mdev_private.h
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -23,6 +23,8 @@ struct mdev_parent {
struct list_head next;
struct kset *mdev_types_kset;
struct list_head type_list;
+ /* Synchronize device creation/removal with parent unregistration */
+ struct rw_semaphore unreg_sem;
};
struct mdev_device {