Commit 0dd1b7fc authored by Jason Gunthorpe's avatar Jason Gunthorpe Committed by Alex Williamson
Browse files

vfio/mtty: Delete mdev_devices_list 



Dan points out that an error case left things on this list. It is also
missing locking in available_instances_show().

Further study shows the list isn't needed at all, just store the total
ports in use in an atomic and delete the whole thing.

Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Fixes: 09177ac9 ("vfio/mtty: Convert to use vfio_register_group_dev()")
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/0-v1-0bc56b362ca7+62-mtty_used_ports_jgg@nvidia.com


Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 742b4c0d

samples/vfio-mdev/mtty.c

+6 −18
Original line number Diff line number Diff line
@@ -144,8 +144,7 @@ struct mdev_state { 
	int nr_ports;

};



static struct mutex mdev_list_lock;

static struct list_head mdev_devices_list;

static atomic_t mdev_used_ports;



static const struct file_operations vd_fops = {

	.owner          = THIS_MODULE,
@@ -733,15 +732,13 @@ static int mtty_probe(struct mdev_device *mdev) 


	mtty_create_config_space(mdev_state);



	mutex_lock(&mdev_list_lock);

	list_add(&mdev_state->next, &mdev_devices_list);

	mutex_unlock(&mdev_list_lock);



	ret = vfio_register_group_dev(&mdev_state->vdev);

	if (ret) {

		kfree(mdev_state);

		return ret;

	}

	atomic_add(mdev_state->nr_ports, &mdev_used_ports);



	dev_set_drvdata(&mdev->dev, mdev_state);

	return 0;

}
@@ -750,10 +747,8 @@ static void mtty_remove(struct mdev_device *mdev) 
{

	struct mdev_state *mdev_state = dev_get_drvdata(&mdev->dev);



	atomic_sub(mdev_state->nr_ports, &mdev_used_ports);

	vfio_unregister_group_dev(&mdev_state->vdev);

	mutex_lock(&mdev_list_lock);

	list_del(&mdev_state->next);

	mutex_unlock(&mdev_list_lock);



	kfree(mdev_state->vconfig);

	kfree(mdev_state);
@@ -1274,14 +1269,10 @@ static ssize_t available_instances_show(struct mdev_type *mtype, 
					struct mdev_type_attribute *attr,

					char *buf)

{

	struct mdev_state *mds;

	unsigned int ports = mtype_get_type_group_id(mtype) + 1;

	int used = 0;



	list_for_each_entry(mds, &mdev_devices_list, next)

		used += mds->nr_ports;



	return sprintf(buf, "%d\n", (MAX_MTTYS - used)/ports);

	return sprintf(buf, "%d\n",

		       (MAX_MTTYS - atomic_read(&mdev_used_ports)) / ports);

}



static MDEV_TYPE_ATTR_RO(available_instances);
@@ -1395,9 +1386,6 @@ static int __init mtty_dev_init(void) 
	ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);

	if (ret)

		goto err_device;



	mutex_init(&mdev_list_lock);

	INIT_LIST_HEAD(&mdev_devices_list);

	return 0;



err_device: