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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: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 09177ac919 ("vfio/mtty: Convert to use vfio_register_group_dev()")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/0-v1-0bc56b362ca7+62-mtty_used_ports_jgg@nvidia.com
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Jason Gunthorpe 2021-06-25 12:56:04 -03:00 committed by Alex Williamson
parent 742b4c0d1e
commit 0dd1b7fc3e
1 changed files with 6 additions and 18 deletions
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24
samples/vfio-mdev/mtty.c
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@ -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: