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![Tetsuo Handa](/assets/img/avatar_default.png)
Flushing system-wide workqueues is dangerous and will be forbidden. Replace system_wq with local wwan_wq. While we are at it, make err_clean_devs: label of wwan_hwsim_init() behave like wwan_hwsim_exit(), for it is theoretically possible to call wwan_hwsim_debugfs_devcreate_write()/wwan_hwsim_debugfs_devdestroy_write() by the moment wwan_hwsim_init_devs() returns. Link: https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com> Reviewed-by: Loic Poulain <loic.poulain@linaro.org> Link: https://lore.kernel.org/r/7390d51f-60e2-3cee-5277-b819a55ceabe@I-love.SAKURA.ne.jp Signed-off-by: Jakub Kicinski <kuba@kernel.org>
559 lines
14 KiB
C
559 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* WWAN device simulator for WWAN framework testing.
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*
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* Copyright (c) 2021, Sergey Ryazanov <ryazanov.s.a@gmail.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/device.h>
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#include <linux/spinlock.h>
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#include <linux/list.h>
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#include <linux/skbuff.h>
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#include <linux/netdevice.h>
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#include <linux/wwan.h>
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#include <linux/debugfs.h>
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#include <linux/workqueue.h>
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#include <net/arp.h>
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static int wwan_hwsim_devsnum = 2;
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module_param_named(devices, wwan_hwsim_devsnum, int, 0444);
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MODULE_PARM_DESC(devices, "Number of simulated devices");
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static struct class *wwan_hwsim_class;
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static struct dentry *wwan_hwsim_debugfs_topdir;
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static struct dentry *wwan_hwsim_debugfs_devcreate;
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static DEFINE_SPINLOCK(wwan_hwsim_devs_lock);
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static LIST_HEAD(wwan_hwsim_devs);
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static unsigned int wwan_hwsim_dev_idx;
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static struct workqueue_struct *wwan_wq;
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struct wwan_hwsim_dev {
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struct list_head list;
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unsigned int id;
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struct device dev;
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struct work_struct del_work;
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struct dentry *debugfs_topdir;
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struct dentry *debugfs_portcreate;
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spinlock_t ports_lock; /* Serialize ports creation/deletion */
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unsigned int port_idx;
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struct list_head ports;
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};
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struct wwan_hwsim_port {
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struct list_head list;
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unsigned int id;
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struct wwan_hwsim_dev *dev;
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struct wwan_port *wwan;
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struct work_struct del_work;
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struct dentry *debugfs_topdir;
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enum { /* AT command parser state */
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AT_PARSER_WAIT_A,
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AT_PARSER_WAIT_T,
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AT_PARSER_WAIT_TERM,
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AT_PARSER_SKIP_LINE,
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} pstate;
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};
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static const struct file_operations wwan_hwsim_debugfs_portdestroy_fops;
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static const struct file_operations wwan_hwsim_debugfs_portcreate_fops;
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static const struct file_operations wwan_hwsim_debugfs_devdestroy_fops;
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static void wwan_hwsim_port_del_work(struct work_struct *work);
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static void wwan_hwsim_dev_del_work(struct work_struct *work);
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static netdev_tx_t wwan_hwsim_netdev_xmit(struct sk_buff *skb,
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struct net_device *ndev)
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{
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ndev->stats.tx_packets++;
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ndev->stats.tx_bytes += skb->len;
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consume_skb(skb);
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return NETDEV_TX_OK;
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}
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static const struct net_device_ops wwan_hwsim_netdev_ops = {
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.ndo_start_xmit = wwan_hwsim_netdev_xmit,
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};
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static void wwan_hwsim_netdev_setup(struct net_device *ndev)
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{
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ndev->netdev_ops = &wwan_hwsim_netdev_ops;
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ndev->needs_free_netdev = true;
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ndev->mtu = ETH_DATA_LEN;
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ndev->min_mtu = ETH_MIN_MTU;
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ndev->max_mtu = ETH_MAX_MTU;
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ndev->type = ARPHRD_NONE;
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ndev->flags = IFF_POINTOPOINT | IFF_NOARP;
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}
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static const struct wwan_ops wwan_hwsim_wwan_rtnl_ops = {
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.priv_size = 0, /* No private data */
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.setup = wwan_hwsim_netdev_setup,
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};
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static int wwan_hwsim_port_start(struct wwan_port *wport)
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{
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struct wwan_hwsim_port *port = wwan_port_get_drvdata(wport);
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port->pstate = AT_PARSER_WAIT_A;
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return 0;
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}
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static void wwan_hwsim_port_stop(struct wwan_port *wport)
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{
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}
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/* Implements a minimalistic AT commands parser that echo input back and
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* reply with 'OK' to each input command. See AT command protocol details in the
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* ITU-T V.250 recomendations document.
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*
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* Be aware that this processor is not fully V.250 compliant.
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*/
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static int wwan_hwsim_port_tx(struct wwan_port *wport, struct sk_buff *in)
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{
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struct wwan_hwsim_port *port = wwan_port_get_drvdata(wport);
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struct sk_buff *out;
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int i, n, s;
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/* Estimate a max possible number of commands by counting the number of
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* termination chars (S3 param, CR by default). And then allocate the
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* output buffer that will be enough to fit the echo and result codes of
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* all commands.
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*/
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for (i = 0, n = 0; i < in->len; ++i)
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if (in->data[i] == '\r')
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n++;
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n = in->len + n * (2 + 2 + 2); /* Output buffer size */
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out = alloc_skb(n, GFP_KERNEL);
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if (!out)
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return -ENOMEM;
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for (i = 0, s = 0; i < in->len; ++i) {
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char c = in->data[i];
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if (port->pstate == AT_PARSER_WAIT_A) {
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if (c == 'A' || c == 'a')
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port->pstate = AT_PARSER_WAIT_T;
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else if (c != '\n') /* Ignore formating char */
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port->pstate = AT_PARSER_SKIP_LINE;
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} else if (port->pstate == AT_PARSER_WAIT_T) {
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if (c == 'T' || c == 't')
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port->pstate = AT_PARSER_WAIT_TERM;
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else
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port->pstate = AT_PARSER_SKIP_LINE;
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} else if (port->pstate == AT_PARSER_WAIT_TERM) {
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if (c != '\r')
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continue;
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/* Consume the trailing formatting char as well */
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if ((i + 1) < in->len && in->data[i + 1] == '\n')
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i++;
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n = i - s + 1;
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memcpy(skb_put(out, n), &in->data[s], n);/* Echo */
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memcpy(skb_put(out, 6), "\r\nOK\r\n", 6);
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s = i + 1;
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port->pstate = AT_PARSER_WAIT_A;
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} else if (port->pstate == AT_PARSER_SKIP_LINE) {
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if (c != '\r')
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continue;
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port->pstate = AT_PARSER_WAIT_A;
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}
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}
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if (i > s) {
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/* Echo the processed portion of a not yet completed command */
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n = i - s;
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memcpy(skb_put(out, n), &in->data[s], n);
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}
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consume_skb(in);
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wwan_port_rx(wport, out);
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return 0;
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}
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static const struct wwan_port_ops wwan_hwsim_port_ops = {
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.start = wwan_hwsim_port_start,
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.stop = wwan_hwsim_port_stop,
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.tx = wwan_hwsim_port_tx,
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};
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static struct wwan_hwsim_port *wwan_hwsim_port_new(struct wwan_hwsim_dev *dev)
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{
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struct wwan_hwsim_port *port;
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char name[0x10];
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int err;
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port = kzalloc(sizeof(*port), GFP_KERNEL);
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if (!port)
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return ERR_PTR(-ENOMEM);
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port->dev = dev;
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spin_lock(&dev->ports_lock);
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port->id = dev->port_idx++;
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spin_unlock(&dev->ports_lock);
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port->wwan = wwan_create_port(&dev->dev, WWAN_PORT_AT,
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&wwan_hwsim_port_ops,
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port);
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if (IS_ERR(port->wwan)) {
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err = PTR_ERR(port->wwan);
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goto err_free_port;
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}
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INIT_WORK(&port->del_work, wwan_hwsim_port_del_work);
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snprintf(name, sizeof(name), "port%u", port->id);
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port->debugfs_topdir = debugfs_create_dir(name, dev->debugfs_topdir);
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debugfs_create_file("destroy", 0200, port->debugfs_topdir, port,
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&wwan_hwsim_debugfs_portdestroy_fops);
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return port;
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err_free_port:
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kfree(port);
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return ERR_PTR(err);
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}
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static void wwan_hwsim_port_del(struct wwan_hwsim_port *port)
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{
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debugfs_remove(port->debugfs_topdir);
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/* Make sure that there is no pending deletion work */
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if (current_work() != &port->del_work)
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cancel_work_sync(&port->del_work);
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wwan_remove_port(port->wwan);
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kfree(port);
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}
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static void wwan_hwsim_port_del_work(struct work_struct *work)
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{
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struct wwan_hwsim_port *port =
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container_of(work, typeof(*port), del_work);
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struct wwan_hwsim_dev *dev = port->dev;
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spin_lock(&dev->ports_lock);
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if (list_empty(&port->list)) {
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/* Someone else deleting port at the moment */
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spin_unlock(&dev->ports_lock);
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return;
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}
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list_del_init(&port->list);
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spin_unlock(&dev->ports_lock);
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wwan_hwsim_port_del(port);
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}
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static void wwan_hwsim_dev_release(struct device *sysdev)
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{
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struct wwan_hwsim_dev *dev = container_of(sysdev, typeof(*dev), dev);
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kfree(dev);
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}
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static struct wwan_hwsim_dev *wwan_hwsim_dev_new(void)
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{
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struct wwan_hwsim_dev *dev;
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int err;
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dev = kzalloc(sizeof(*dev), GFP_KERNEL);
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if (!dev)
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return ERR_PTR(-ENOMEM);
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spin_lock(&wwan_hwsim_devs_lock);
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dev->id = wwan_hwsim_dev_idx++;
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spin_unlock(&wwan_hwsim_devs_lock);
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dev->dev.release = wwan_hwsim_dev_release;
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dev->dev.class = wwan_hwsim_class;
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dev_set_name(&dev->dev, "hwsim%u", dev->id);
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spin_lock_init(&dev->ports_lock);
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INIT_LIST_HEAD(&dev->ports);
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err = device_register(&dev->dev);
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if (err)
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goto err_free_dev;
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INIT_WORK(&dev->del_work, wwan_hwsim_dev_del_work);
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err = wwan_register_ops(&dev->dev, &wwan_hwsim_wwan_rtnl_ops, dev, 1);
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if (err)
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goto err_unreg_dev;
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dev->debugfs_topdir = debugfs_create_dir(dev_name(&dev->dev),
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wwan_hwsim_debugfs_topdir);
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debugfs_create_file("destroy", 0200, dev->debugfs_topdir, dev,
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&wwan_hwsim_debugfs_devdestroy_fops);
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dev->debugfs_portcreate =
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debugfs_create_file("portcreate", 0200,
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dev->debugfs_topdir, dev,
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&wwan_hwsim_debugfs_portcreate_fops);
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return dev;
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err_unreg_dev:
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device_unregister(&dev->dev);
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/* Memory will be freed in the device release callback */
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return ERR_PTR(err);
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err_free_dev:
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kfree(dev);
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return ERR_PTR(err);
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}
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static void wwan_hwsim_dev_del(struct wwan_hwsim_dev *dev)
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{
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debugfs_remove(dev->debugfs_portcreate); /* Avoid new ports */
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spin_lock(&dev->ports_lock);
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while (!list_empty(&dev->ports)) {
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struct wwan_hwsim_port *port;
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port = list_first_entry(&dev->ports, struct wwan_hwsim_port,
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list);
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list_del_init(&port->list);
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spin_unlock(&dev->ports_lock);
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wwan_hwsim_port_del(port);
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spin_lock(&dev->ports_lock);
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}
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spin_unlock(&dev->ports_lock);
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debugfs_remove(dev->debugfs_topdir);
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/* This will remove all child netdev(s) */
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wwan_unregister_ops(&dev->dev);
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/* Make sure that there is no pending deletion work */
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if (current_work() != &dev->del_work)
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cancel_work_sync(&dev->del_work);
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device_unregister(&dev->dev);
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/* Memory will be freed in the device release callback */
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}
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static void wwan_hwsim_dev_del_work(struct work_struct *work)
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{
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struct wwan_hwsim_dev *dev = container_of(work, typeof(*dev), del_work);
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spin_lock(&wwan_hwsim_devs_lock);
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if (list_empty(&dev->list)) {
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/* Someone else deleting device at the moment */
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spin_unlock(&wwan_hwsim_devs_lock);
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return;
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}
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list_del_init(&dev->list);
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spin_unlock(&wwan_hwsim_devs_lock);
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wwan_hwsim_dev_del(dev);
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}
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static ssize_t wwan_hwsim_debugfs_portdestroy_write(struct file *file,
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const char __user *usrbuf,
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size_t count, loff_t *ppos)
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{
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struct wwan_hwsim_port *port = file->private_data;
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/* We can not delete port here since it will cause a deadlock due to
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* waiting this callback to finish in the debugfs_remove() call. So,
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* use workqueue.
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*/
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queue_work(wwan_wq, &port->del_work);
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return count;
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}
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static const struct file_operations wwan_hwsim_debugfs_portdestroy_fops = {
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.write = wwan_hwsim_debugfs_portdestroy_write,
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.open = simple_open,
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.llseek = noop_llseek,
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};
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static ssize_t wwan_hwsim_debugfs_portcreate_write(struct file *file,
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const char __user *usrbuf,
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size_t count, loff_t *ppos)
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{
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struct wwan_hwsim_dev *dev = file->private_data;
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struct wwan_hwsim_port *port;
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port = wwan_hwsim_port_new(dev);
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if (IS_ERR(port))
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return PTR_ERR(port);
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spin_lock(&dev->ports_lock);
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list_add_tail(&port->list, &dev->ports);
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spin_unlock(&dev->ports_lock);
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return count;
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}
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static const struct file_operations wwan_hwsim_debugfs_portcreate_fops = {
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.write = wwan_hwsim_debugfs_portcreate_write,
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.open = simple_open,
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.llseek = noop_llseek,
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};
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static ssize_t wwan_hwsim_debugfs_devdestroy_write(struct file *file,
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const char __user *usrbuf,
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size_t count, loff_t *ppos)
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{
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struct wwan_hwsim_dev *dev = file->private_data;
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/* We can not delete device here since it will cause a deadlock due to
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* waiting this callback to finish in the debugfs_remove() call. So,
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* use workqueue.
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*/
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queue_work(wwan_wq, &dev->del_work);
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return count;
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}
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static const struct file_operations wwan_hwsim_debugfs_devdestroy_fops = {
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.write = wwan_hwsim_debugfs_devdestroy_write,
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.open = simple_open,
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.llseek = noop_llseek,
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};
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static ssize_t wwan_hwsim_debugfs_devcreate_write(struct file *file,
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const char __user *usrbuf,
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size_t count, loff_t *ppos)
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{
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struct wwan_hwsim_dev *dev;
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dev = wwan_hwsim_dev_new();
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if (IS_ERR(dev))
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return PTR_ERR(dev);
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spin_lock(&wwan_hwsim_devs_lock);
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list_add_tail(&dev->list, &wwan_hwsim_devs);
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spin_unlock(&wwan_hwsim_devs_lock);
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return count;
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}
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static const struct file_operations wwan_hwsim_debugfs_devcreate_fops = {
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.write = wwan_hwsim_debugfs_devcreate_write,
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.open = simple_open,
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.llseek = noop_llseek,
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};
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static int __init wwan_hwsim_init_devs(void)
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{
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struct wwan_hwsim_dev *dev;
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int i, j;
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for (i = 0; i < wwan_hwsim_devsnum; ++i) {
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dev = wwan_hwsim_dev_new();
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if (IS_ERR(dev))
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return PTR_ERR(dev);
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spin_lock(&wwan_hwsim_devs_lock);
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list_add_tail(&dev->list, &wwan_hwsim_devs);
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spin_unlock(&wwan_hwsim_devs_lock);
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/* Create a couple of ports per each device to accelerate
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* the simulator readiness time.
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*/
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for (j = 0; j < 2; ++j) {
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struct wwan_hwsim_port *port;
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port = wwan_hwsim_port_new(dev);
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if (IS_ERR(port))
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return PTR_ERR(port);
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spin_lock(&dev->ports_lock);
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list_add_tail(&port->list, &dev->ports);
|
|
spin_unlock(&dev->ports_lock);
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void wwan_hwsim_free_devs(void)
|
|
{
|
|
struct wwan_hwsim_dev *dev;
|
|
|
|
spin_lock(&wwan_hwsim_devs_lock);
|
|
while (!list_empty(&wwan_hwsim_devs)) {
|
|
dev = list_first_entry(&wwan_hwsim_devs, struct wwan_hwsim_dev,
|
|
list);
|
|
list_del_init(&dev->list);
|
|
spin_unlock(&wwan_hwsim_devs_lock);
|
|
wwan_hwsim_dev_del(dev);
|
|
spin_lock(&wwan_hwsim_devs_lock);
|
|
}
|
|
spin_unlock(&wwan_hwsim_devs_lock);
|
|
}
|
|
|
|
static int __init wwan_hwsim_init(void)
|
|
{
|
|
int err;
|
|
|
|
if (wwan_hwsim_devsnum < 0 || wwan_hwsim_devsnum > 128)
|
|
return -EINVAL;
|
|
|
|
wwan_wq = alloc_workqueue("wwan_wq", 0, 0);
|
|
if (!wwan_wq)
|
|
return -ENOMEM;
|
|
|
|
wwan_hwsim_class = class_create(THIS_MODULE, "wwan_hwsim");
|
|
if (IS_ERR(wwan_hwsim_class)) {
|
|
err = PTR_ERR(wwan_hwsim_class);
|
|
goto err_wq_destroy;
|
|
}
|
|
|
|
wwan_hwsim_debugfs_topdir = debugfs_create_dir("wwan_hwsim", NULL);
|
|
wwan_hwsim_debugfs_devcreate =
|
|
debugfs_create_file("devcreate", 0200,
|
|
wwan_hwsim_debugfs_topdir, NULL,
|
|
&wwan_hwsim_debugfs_devcreate_fops);
|
|
|
|
err = wwan_hwsim_init_devs();
|
|
if (err)
|
|
goto err_clean_devs;
|
|
|
|
return 0;
|
|
|
|
err_clean_devs:
|
|
debugfs_remove(wwan_hwsim_debugfs_devcreate); /* Avoid new devs */
|
|
wwan_hwsim_free_devs();
|
|
flush_workqueue(wwan_wq); /* Wait deletion works completion */
|
|
debugfs_remove(wwan_hwsim_debugfs_topdir);
|
|
class_destroy(wwan_hwsim_class);
|
|
err_wq_destroy:
|
|
destroy_workqueue(wwan_wq);
|
|
|
|
return err;
|
|
}
|
|
|
|
static void __exit wwan_hwsim_exit(void)
|
|
{
|
|
debugfs_remove(wwan_hwsim_debugfs_devcreate); /* Avoid new devs */
|
|
wwan_hwsim_free_devs();
|
|
flush_workqueue(wwan_wq); /* Wait deletion works completion */
|
|
debugfs_remove(wwan_hwsim_debugfs_topdir);
|
|
class_destroy(wwan_hwsim_class);
|
|
destroy_workqueue(wwan_wq);
|
|
}
|
|
|
|
module_init(wwan_hwsim_init);
|
|
module_exit(wwan_hwsim_exit);
|
|
|
|
MODULE_AUTHOR("Sergey Ryazanov");
|
|
MODULE_DESCRIPTION("Device simulator for WWAN framework");
|
|
MODULE_LICENSE("GPL");
|