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9f0248ea47
The WWAN netdev ops owner holding was used to protect from the unexpected memory disappear. This approach causes a dependency cycle (driver -> core -> driver) and effectively prevents a WWAN driver unloading. E.g. WWAN hwsim could not be unloaded until all simulated devices are removed: ~# modprobe wwan_hwsim devices=2 ~# lsmod | grep wwan wwan_hwsim 16384 2 wwan 20480 1 wwan_hwsim ~# rmmod wwan_hwsim rmmod: ERROR: Module wwan_hwsim is in use ~# echo > /sys/kernel/debug/wwan_hwsim/hwsim0/destroy ~# echo > /sys/kernel/debug/wwan_hwsim/hwsim1/destroy ~# lsmod | grep wwan wwan_hwsim 16384 0 wwan 20480 1 wwan_hwsim ~# rmmod wwan_hwsim For a real device driver this will cause an inability to unload module until a served device is physically detached. Since the last commit we are removing all child netdev(s) when a driver unregister the netdev ops. This allows us to permit the driver unloading, since any sane driver will call ops unregistering on a device deinitialization. So, remove the holding of an ops owner to make it easier to unload a driver module. The owner field has also beed removed from the ops structure as there are no more users of this field. Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com> Reviewed-by: Loic Poulain <loic.poulain@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
150 lines
4.5 KiB
C
150 lines
4.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/* Copyright (c) 2021, Linaro Ltd <loic.poulain@linaro.org> */
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#ifndef __WWAN_H
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#define __WWAN_H
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/poll.h>
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#include <linux/skbuff.h>
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#include <linux/netlink.h>
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/**
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* enum wwan_port_type - WWAN port types
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* @WWAN_PORT_AT: AT commands
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* @WWAN_PORT_MBIM: Mobile Broadband Interface Model control
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* @WWAN_PORT_QMI: Qcom modem/MSM interface for modem control
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* @WWAN_PORT_QCDM: Qcom Modem diagnostic interface
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* @WWAN_PORT_FIREHOSE: XML based command protocol
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*
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* @WWAN_PORT_MAX: Highest supported port types
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* @WWAN_PORT_UNKNOWN: Special value to indicate an unknown port type
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* @__WWAN_PORT_MAX: Internal use
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*/
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enum wwan_port_type {
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WWAN_PORT_AT,
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WWAN_PORT_MBIM,
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WWAN_PORT_QMI,
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WWAN_PORT_QCDM,
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WWAN_PORT_FIREHOSE,
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/* Add new port types above this line */
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__WWAN_PORT_MAX,
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WWAN_PORT_MAX = __WWAN_PORT_MAX - 1,
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WWAN_PORT_UNKNOWN,
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};
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struct wwan_port;
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/** struct wwan_port_ops - The WWAN port operations
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* @start: The routine for starting the WWAN port device.
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* @stop: The routine for stopping the WWAN port device.
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* @tx: Non-blocking routine that sends WWAN port protocol data to the device.
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* @tx_blocking: Optional blocking routine that sends WWAN port protocol data
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* to the device.
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* @tx_poll: Optional routine that sets additional TX poll flags.
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*
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* The wwan_port_ops structure contains a list of low-level operations
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* that control a WWAN port device. All functions are mandatory unless specified.
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*/
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struct wwan_port_ops {
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int (*start)(struct wwan_port *port);
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void (*stop)(struct wwan_port *port);
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int (*tx)(struct wwan_port *port, struct sk_buff *skb);
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/* Optional operations */
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int (*tx_blocking)(struct wwan_port *port, struct sk_buff *skb);
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__poll_t (*tx_poll)(struct wwan_port *port, struct file *filp,
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poll_table *wait);
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};
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/**
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* wwan_create_port - Add a new WWAN port
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* @parent: Device to use as parent and shared by all WWAN ports
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* @type: WWAN port type
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* @ops: WWAN port operations
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* @drvdata: Pointer to caller driver data
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*
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* Allocate and register a new WWAN port. The port will be automatically exposed
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* to user as a character device and attached to the right virtual WWAN device,
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* based on the parent pointer. The parent pointer is the device shared by all
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* components of a same WWAN modem (e.g. USB dev, PCI dev, MHI controller...).
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*
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* drvdata will be placed in the WWAN port device driver data and can be
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* retrieved with wwan_port_get_drvdata().
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*
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* This function must be balanced with a call to wwan_remove_port().
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*
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* Returns a valid pointer to wwan_port on success or PTR_ERR on failure
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*/
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struct wwan_port *wwan_create_port(struct device *parent,
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enum wwan_port_type type,
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const struct wwan_port_ops *ops,
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void *drvdata);
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/**
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* wwan_remove_port - Remove a WWAN port
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* @port: WWAN port to remove
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*
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* Remove a previously created port.
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*/
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void wwan_remove_port(struct wwan_port *port);
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/**
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* wwan_port_rx - Receive data from the WWAN port
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* @port: WWAN port for which data is received
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* @skb: Pointer to the rx buffer
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*
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* A port driver calls this function upon data reception (MBIM, AT...).
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*/
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void wwan_port_rx(struct wwan_port *port, struct sk_buff *skb);
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/**
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* wwan_port_txoff - Stop TX on WWAN port
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* @port: WWAN port for which TX must be stopped
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*
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* Used for TX flow control, a port driver calls this function to indicate TX
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* is temporary unavailable (e.g. due to ring buffer fullness).
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*/
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void wwan_port_txoff(struct wwan_port *port);
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/**
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* wwan_port_txon - Restart TX on WWAN port
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* @port: WWAN port for which TX must be restarted
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*
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* Used for TX flow control, a port driver calls this function to indicate TX
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* is available again.
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*/
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void wwan_port_txon(struct wwan_port *port);
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/**
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* wwan_port_get_drvdata - Retrieve driver data from a WWAN port
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* @port: Related WWAN port
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*/
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void *wwan_port_get_drvdata(struct wwan_port *port);
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/**
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* struct wwan_ops - WWAN device ops
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* @priv_size: size of private netdev data area
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* @setup: set up a new netdev
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* @newlink: register the new netdev
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* @dellink: remove the given netdev
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*/
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struct wwan_ops {
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unsigned int priv_size;
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void (*setup)(struct net_device *dev);
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int (*newlink)(void *ctxt, struct net_device *dev,
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u32 if_id, struct netlink_ext_ack *extack);
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void (*dellink)(void *ctxt, struct net_device *dev,
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struct list_head *head);
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};
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int wwan_register_ops(struct device *parent, const struct wwan_ops *ops,
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void *ctxt);
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void wwan_unregister_ops(struct device *parent);
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#endif /* __WWAN_H */
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