static DEFINE_MUTEX(ublk_ctl_mutex);
+/*
+ * Max ublk devices allowed to add
+ *
+ * It can be extended to one per-user limit in future or even controlled
+ * by cgroup.
+ */
+static unsigned int ublks_max = 64;
+static unsigned int ublks_added; /* protected by ublk_ctl_mutex */
+
static struct miscdevice ublk_misc;
static void ublk_dev_param_basic_apply(struct ublk_device *ub)
ret = cdev_device_add(&ub->cdev, dev);
if (ret)
goto fail;
+
+ ublks_added++;
return 0;
fail:
put_device(dev);
cancel_work_sync(&ub->quiesce_work);
cdev_device_del(&ub->cdev, &ub->cdev_dev);
put_device(&ub->cdev_dev);
+ ublks_added--;
}
static struct ublk_device *ublk_get_device_from_id(int idx)
if (ret)
return ret;
+ ret = -EACCES;
+ if (ublks_added >= ublks_max)
+ goto out_unlock;
+
ret = -ENOMEM;
ub = kzalloc(sizeof(*ub), GFP_KERNEL);
if (!ub)
module_init(ublk_init);
module_exit(ublk_exit);
+module_param(ublks_max, int, 0444);
+MODULE_PARM_DESC(ublks_max, "max number of ublk devices allowed to add(default: 64)");
+
MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
MODULE_LICENSE("GPL");