From 88b710532e53de2466d1033fb1d5125aabf3215a Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Sat, 12 Jun 2021 10:20:56 +0200 Subject: [PATCH] wwan: add interface creation support Add support to create (and destroy) interfaces via a new rtnetlink kind "wwan". The responsible driver has to use the new wwan_register_ops() to make this possible. Signed-off-by: Johannes Berg Signed-off-by: Sergey Ryazanov Signed-off-by: Loic Poulain Signed-off-by: David S. Miller --- drivers/net/wwan/wwan_core.c | 245 +++++++++++++++++++++++++++++++++++++++++-- include/linux/wwan.h | 24 +++++ include/uapi/linux/wwan.h | 16 +++ net/core/rtnetlink.c | 1 + 4 files changed, 279 insertions(+), 7 deletions(-) create mode 100644 include/uapi/linux/wwan.h diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c index 45a41ae..7e72804 100644 --- a/drivers/net/wwan/wwan_core.c +++ b/drivers/net/wwan/wwan_core.c @@ -14,6 +14,8 @@ #include #include #include +#include +#include /* Maximum number of minors in use */ #define WWAN_MAX_MINORS (1 << MINORBITS) @@ -35,10 +37,16 @@ static int wwan_major; * * @id: WWAN device unique ID. * @dev: Underlying device. + * @port_id: Current available port ID to pick. + * @ops: wwan device ops + * @ops_ctxt: context to pass to ops */ struct wwan_device { unsigned int id; struct device dev; + atomic_t port_id; + const struct wwan_ops *ops; + void *ops_ctxt; }; /** @@ -102,7 +110,8 @@ static const struct device_type wwan_dev_type = { static int wwan_dev_parent_match(struct device *dev, const void *parent) { - return (dev->type == &wwan_dev_type && dev->parent == parent); + return (dev->type == &wwan_dev_type && + (dev->parent == parent || dev == parent)); } static struct wwan_device *wwan_dev_get_by_parent(struct device *parent) @@ -116,6 +125,23 @@ static struct wwan_device *wwan_dev_get_by_parent(struct device *parent) return to_wwan_dev(dev); } +static int wwan_dev_name_match(struct device *dev, const void *name) +{ + return dev->type == &wwan_dev_type && + strcmp(dev_name(dev), name) == 0; +} + +static struct wwan_device *wwan_dev_get_by_name(const char *name) +{ + struct device *dev; + + dev = class_find_device(wwan_class, NULL, name, wwan_dev_name_match); + if (!dev) + return ERR_PTR(-ENODEV); + + return to_wwan_dev(dev); +} + /* This function allocates and registers a new WWAN device OR if a WWAN device * already exist for the given parent, it gets a reference and return it. * This function is not exported (for now), it is called indirectly via @@ -180,9 +206,14 @@ static void wwan_remove_dev(struct wwan_device *wwandev) /* WWAN device is created and registered (get+add) along with its first * child port, and subsequent port registrations only grab a reference * (get). The WWAN device must then be unregistered (del+put) along with - * its latest port, and reference simply dropped (put) otherwise. + * its last port, and reference simply dropped (put) otherwise. In the + * same fashion, we must not unregister it when the ops are still there. */ - ret = device_for_each_child(&wwandev->dev, NULL, is_wwan_child); + if (wwandev->ops) + ret = 1; + else + ret = device_for_each_child(&wwandev->dev, NULL, is_wwan_child); + if (!ret) device_unregister(&wwandev->dev); else @@ -750,26 +781,226 @@ static const struct file_operations wwan_port_fops = { .llseek = noop_llseek, }; +/** + * wwan_register_ops - register WWAN device ops + * @parent: Device to use as parent and shared by all WWAN ports and + * created netdevs + * @ops: operations to register + * @ctxt: context to pass to operations + * + * Returns: 0 on success, a negative error code on failure + */ +int wwan_register_ops(struct device *parent, const struct wwan_ops *ops, + void *ctxt) +{ + struct wwan_device *wwandev; + + if (WARN_ON(!parent || !ops)) + return -EINVAL; + + wwandev = wwan_create_dev(parent); + if (!wwandev) + return -ENOMEM; + + if (WARN_ON(wwandev->ops)) { + wwan_remove_dev(wwandev); + return -EBUSY; + } + + if (!try_module_get(ops->owner)) { + wwan_remove_dev(wwandev); + return -ENODEV; + } + + wwandev->ops = ops; + wwandev->ops_ctxt = ctxt; + + return 0; +} +EXPORT_SYMBOL_GPL(wwan_register_ops); + +/** + * wwan_unregister_ops - remove WWAN device ops + * @parent: Device to use as parent and shared by all WWAN ports and + * created netdevs + */ +void wwan_unregister_ops(struct device *parent) +{ + struct wwan_device *wwandev = wwan_dev_get_by_parent(parent); + bool has_ops; + + if (WARN_ON(IS_ERR(wwandev))) + return; + + has_ops = wwandev->ops; + + /* put the reference obtained by wwan_dev_get_by_parent(), + * we should still have one (that the owner is giving back + * now) due to the ops being assigned, check that below + * and return if not. + */ + put_device(&wwandev->dev); + + if (WARN_ON(!has_ops)) + return; + + module_put(wwandev->ops->owner); + + wwandev->ops = NULL; + wwandev->ops_ctxt = NULL; + wwan_remove_dev(wwandev); +} +EXPORT_SYMBOL_GPL(wwan_unregister_ops); + +static int wwan_rtnl_validate(struct nlattr *tb[], struct nlattr *data[], + struct netlink_ext_ack *extack) +{ + if (!data) + return -EINVAL; + + if (!tb[IFLA_PARENT_DEV_NAME]) + return -EINVAL; + + if (!data[IFLA_WWAN_LINK_ID]) + return -EINVAL; + + return 0; +} + +static struct device_type wwan_type = { .name = "wwan" }; + +static struct net_device *wwan_rtnl_alloc(struct nlattr *tb[], + const char *ifname, + unsigned char name_assign_type, + unsigned int num_tx_queues, + unsigned int num_rx_queues) +{ + const char *devname = nla_data(tb[IFLA_PARENT_DEV_NAME]); + struct wwan_device *wwandev = wwan_dev_get_by_name(devname); + struct net_device *dev; + + if (IS_ERR(wwandev)) + return ERR_CAST(wwandev); + + /* only supported if ops were registered (not just ports) */ + if (!wwandev->ops) { + dev = ERR_PTR(-EOPNOTSUPP); + goto out; + } + + dev = alloc_netdev_mqs(wwandev->ops->priv_size, ifname, name_assign_type, + wwandev->ops->setup, num_tx_queues, num_rx_queues); + + if (dev) { + SET_NETDEV_DEV(dev, &wwandev->dev); + SET_NETDEV_DEVTYPE(dev, &wwan_type); + } + +out: + /* release the reference */ + put_device(&wwandev->dev); + return dev; +} + +static int wwan_rtnl_newlink(struct net *src_net, struct net_device *dev, + struct nlattr *tb[], struct nlattr *data[], + struct netlink_ext_ack *extack) +{ + struct wwan_device *wwandev = wwan_dev_get_by_parent(dev->dev.parent); + u32 link_id = nla_get_u32(data[IFLA_WWAN_LINK_ID]); + int ret; + + if (IS_ERR(wwandev)) + return PTR_ERR(wwandev); + + /* shouldn't have a netdev (left) with us as parent so WARN */ + if (WARN_ON(!wwandev->ops)) { + ret = -EOPNOTSUPP; + goto out; + } + + if (wwandev->ops->newlink) + ret = wwandev->ops->newlink(wwandev->ops_ctxt, dev, + link_id, extack); + else + ret = register_netdevice(dev); + +out: + /* release the reference */ + put_device(&wwandev->dev); + return ret; +} + +static void wwan_rtnl_dellink(struct net_device *dev, struct list_head *head) +{ + struct wwan_device *wwandev = wwan_dev_get_by_parent(dev->dev.parent); + + if (IS_ERR(wwandev)) + return; + + /* shouldn't have a netdev (left) with us as parent so WARN */ + if (WARN_ON(!wwandev->ops)) + goto out; + + if (wwandev->ops->dellink) + wwandev->ops->dellink(wwandev->ops_ctxt, dev, head); + else + unregister_netdevice(dev); + +out: + /* release the reference */ + put_device(&wwandev->dev); +} + +static const struct nla_policy wwan_rtnl_policy[IFLA_WWAN_MAX + 1] = { + [IFLA_WWAN_LINK_ID] = { .type = NLA_U32 }, +}; + +static struct rtnl_link_ops wwan_rtnl_link_ops __read_mostly = { + .kind = "wwan", + .maxtype = __IFLA_WWAN_MAX, + .alloc = wwan_rtnl_alloc, + .validate = wwan_rtnl_validate, + .newlink = wwan_rtnl_newlink, + .dellink = wwan_rtnl_dellink, + .policy = wwan_rtnl_policy, +}; + static int __init wwan_init(void) { + int err; + + err = rtnl_link_register(&wwan_rtnl_link_ops); + if (err) + return err; + wwan_class = class_create(THIS_MODULE, "wwan"); - if (IS_ERR(wwan_class)) - return PTR_ERR(wwan_class); + if (IS_ERR(wwan_class)) { + err = PTR_ERR(wwan_class); + goto unregister; + } /* chrdev used for wwan ports */ wwan_major = __register_chrdev(0, 0, WWAN_MAX_MINORS, "wwan_port", &wwan_port_fops); if (wwan_major < 0) { - class_destroy(wwan_class); - return wwan_major; + err = wwan_major; + goto destroy; } return 0; + +destroy: + class_destroy(wwan_class); +unregister: + rtnl_link_unregister(&wwan_rtnl_link_ops); + return err; } static void __exit wwan_exit(void) { __unregister_chrdev(wwan_major, 0, WWAN_MAX_MINORS, "wwan_port"); + rtnl_link_unregister(&wwan_rtnl_link_ops); class_destroy(wwan_class); } diff --git a/include/linux/wwan.h b/include/linux/wwan.h index fa33cc1..430a3a0 100644 --- a/include/linux/wwan.h +++ b/include/linux/wwan.h @@ -7,6 +7,7 @@ #include #include #include +#include /** * enum wwan_port_type - WWAN port types @@ -116,4 +117,27 @@ void wwan_port_txon(struct wwan_port *port); */ void *wwan_port_get_drvdata(struct wwan_port *port); +/** + * struct wwan_ops - WWAN device ops + * @owner: module owner of the WWAN ops + * @priv_size: size of private netdev data area + * @setup: set up a new netdev + * @newlink: register the new netdev + * @dellink: remove the given netdev + */ +struct wwan_ops { + struct module *owner; + unsigned int priv_size; + void (*setup)(struct net_device *dev); + int (*newlink)(void *ctxt, struct net_device *dev, + u32 if_id, struct netlink_ext_ack *extack); + void (*dellink)(void *ctxt, struct net_device *dev, + struct list_head *head); +}; + +int wwan_register_ops(struct device *parent, const struct wwan_ops *ops, + void *ctxt); + +void wwan_unregister_ops(struct device *parent); + #endif /* __WWAN_H */ diff --git a/include/uapi/linux/wwan.h b/include/uapi/linux/wwan.h new file mode 100644 index 0000000..32a2720 --- /dev/null +++ b/include/uapi/linux/wwan.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */ +/* + * Copyright (C) 2021 Intel Corporation. + */ +#ifndef _UAPI_WWAN_H_ +#define _UAPI_WWAN_H_ + +enum { + IFLA_WWAN_UNSPEC, + IFLA_WWAN_LINK_ID, /* u32 */ + + __IFLA_WWAN_MAX +}; +#define IFLA_WWAN_MAX (__IFLA_WWAN_MAX - 1) + +#endif /* _UAPI_WWAN_H_ */ diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 170e97f..5baa86b 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1890,6 +1890,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = { [IFLA_PERM_ADDRESS] = { .type = NLA_REJECT }, [IFLA_PROTO_DOWN_REASON] = { .type = NLA_NESTED }, [IFLA_NEW_IFINDEX] = NLA_POLICY_MIN(NLA_S32, 1), + [IFLA_PARENT_DEV_NAME] = { .type = NLA_NUL_STRING }, }; static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = { -- 2.7.4