drivers/usb/mon/mon_main.c - kernel/msm-4.19 - Gitiles

 /*
  * The USB Monitor, inspired by Dave Harding's USBMon.
  *
  * mon_main.c: Main file, module initiation and exit, registrations, etc.
  *
  * Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/usb.h>
 #include <linux/debugfs.h>
 #include <linux/smp_lock.h>

 #include "usb_mon.h"
 #include "../core/hcd.h"

 static void mon_submit(struct usb_bus *ubus, struct urb *urb);
 static void mon_complete(struct usb_bus *ubus, struct urb *urb);
 static void mon_stop(struct mon_bus *mbus);
 static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus);
 static void mon_bus_drop(struct kref *r);
 static void mon_bus_init(struct dentry *mondir, struct usb_bus *ubus);

 DECLARE_MUTEX(mon_lock);

 static struct dentry *mon_dir;		/* /dbg/usbmon */
 static LIST_HEAD(mon_buses);		/* All buses we know: struct mon_bus */

 /*
  * Link a reader into the bus.
  *
  * This must be called with mon_lock taken because of mbus->ref.
  */
 void mon_reader_add(struct mon_bus *mbus, struct mon_reader *r)
 {
 	unsigned long flags;
 	struct usb_bus *ubus;

 	spin_lock_irqsave(&mbus->lock, flags);
 	if (mbus->nreaders == 0) {
 		ubus = mbus->u_bus;
 		if (ubus->monitored) {
 			/*
 			 * Something is really broken, refuse to go on and
 			 * possibly corrupt ops pointers or worse.
 			 */
 			printk(KERN_ERR TAG ": bus %d is already monitored\n",
 			    ubus->busnum);
 			spin_unlock_irqrestore(&mbus->lock, flags);
 			return;
 		}
 		ubus->monitored = 1;
 	}
 	mbus->nreaders++;
 	list_add_tail(&r->r_link, &mbus->r_list);
 	spin_unlock_irqrestore(&mbus->lock, flags);

 	kref_get(&mbus->ref);
 }

 /*
  * Unlink reader from the bus.
  *
  * This is called with mon_lock taken, so we can decrement mbus->ref.
  */
 void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r)
 {
 	unsigned long flags;

 	spin_lock_irqsave(&mbus->lock, flags);
 	list_del(&r->r_link);
 	--mbus->nreaders;
 	if (mbus->nreaders == 0)
 		mon_stop(mbus);
 	spin_unlock_irqrestore(&mbus->lock, flags);

 	kref_put(&mbus->ref, mon_bus_drop);
 }

 /*
  */
 static void mon_submit(struct usb_bus *ubus, struct urb *urb)
 {
 	struct mon_bus *mbus;
 	unsigned long flags;
 	struct list_head *pos;
 	struct mon_reader *r;

 	mbus = ubus->mon_bus;
 	if (mbus == NULL)
 		goto out_unlocked;

 	spin_lock_irqsave(&mbus->lock, flags);
 	if (mbus->nreaders == 0)
 		goto out_locked;

 	list_for_each (pos, &mbus->r_list) {
 		r = list_entry(pos, struct mon_reader, r_link);
 		r->rnf_submit(r->r_data, urb);
 	}

 	spin_unlock_irqrestore(&mbus->lock, flags);
 	return;

 out_locked:
 	spin_unlock_irqrestore(&mbus->lock, flags);
 out_unlocked:
 	return;
 }

 /*
  */
 static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int err)
 {
 	struct mon_bus *mbus;

 	mbus = ubus->mon_bus;
 	if (mbus == NULL)
 		goto out_unlocked;

 	/*
 	 * XXX Capture the error code and the 'E' event.
 	 */

 	return;

 out_unlocked:
 	return;
 }

 /*
  */
 static void mon_complete(struct usb_bus *ubus, struct urb *urb)
 {
 	struct mon_bus *mbus;
 	unsigned long flags;
 	struct list_head *pos;
 	struct mon_reader *r;

 	mbus = ubus->mon_bus;
 	if (mbus == NULL) {
 		/*
 		 * This should not happen.
 		 * At this point we do not even know the bus number...
 		 */
 		printk(KERN_ERR TAG ": Null mon bus in URB, pipe 0x%x\n",
 		    urb->pipe);
 		return;
 	}

 	spin_lock_irqsave(&mbus->lock, flags);
 	list_for_each (pos, &mbus->r_list) {
 		r = list_entry(pos, struct mon_reader, r_link);
 		r->rnf_complete(r->r_data, urb);
 	}
 	spin_unlock_irqrestore(&mbus->lock, flags);
 }

 /* int (*unlink_urb) (struct urb *urb, int status); */

 /*
  * Stop monitoring.
  * Obviously this must be well locked, so no need to play with mb's.
  */
 static void mon_stop(struct mon_bus *mbus)
 {
 	struct usb_bus *ubus = mbus->u_bus;

 	/*
 	 * A stop can be called for a dissolved mon_bus in case of
 	 * a reader staying across an rmmod foo_hcd.
 	 */
 	if (ubus != NULL) {
 		ubus->monitored = 0;
 		mb();
 	}
 }

 /*
  * Add a USB bus (usually by a modprobe foo-hcd)
  *
  * This does not return an error code because the core cannot care less
  * if monitoring is not established.
  */
 static void mon_bus_add(struct usb_bus *ubus)
 {
 	mon_bus_init(mon_dir, ubus);
 }

 /*
  * Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
  */
 static void mon_bus_remove(struct usb_bus *ubus)
 {
 	struct mon_bus *mbus = ubus->mon_bus;

 	down(&mon_lock);
 	list_del(&mbus->bus_link);
 	debugfs_remove(mbus->dent_t);
 	debugfs_remove(mbus->dent_s);

 	mon_dissolve(mbus, ubus);
 	kref_put(&mbus->ref, mon_bus_drop);
 	up(&mon_lock);
 }

 /*
  * Ops
  */
 static struct usb_mon_operations mon_ops_0 = {
 	.urb_submit =	mon_submit,
 	.urb_submit_error = mon_submit_error,
 	.urb_complete =	mon_complete,
 	.bus_add =	mon_bus_add,
 	.bus_remove =	mon_bus_remove,
 };

 /*
  * Tear usb_bus and mon_bus apart.
  */
 static void mon_dissolve(struct mon_bus *mbus, struct usb_bus *ubus)
 {

 	/*
 	 * Never happens, but...
 	 */
 	if (ubus->monitored) {
 		printk(KERN_ERR TAG ": bus %d is dissolved while monitored\n",
 		    ubus->busnum);
 		ubus->monitored = 0;
 		mb();
 	}

 	ubus->mon_bus = NULL;
 	mbus->u_bus = NULL;
 	mb();
 	// usb_bus_put(ubus);
 }

 /*
  */
 static void mon_bus_drop(struct kref *r)
 {
 	struct mon_bus *mbus = container_of(r, struct mon_bus, ref);
 	kfree(mbus);
 }

 /*
  * Initialize a bus for us:
  *  - allocate mon_bus
  *  - refcount USB bus struct
  *  - link
  */
 static void mon_bus_init(struct dentry *mondir, struct usb_bus *ubus)
 {
 	struct dentry *d;
 	struct mon_bus *mbus;
 	enum { NAMESZ = 10 };
 	char name[NAMESZ];
 	int rc;

 	if ((mbus = kmalloc(sizeof(struct mon_bus), GFP_KERNEL)) == NULL)
 		goto err_alloc;
 	memset(mbus, 0, sizeof(struct mon_bus));
 	kref_init(&mbus->ref);
 	spin_lock_init(&mbus->lock);
 	INIT_LIST_HEAD(&mbus->r_list);

 	/*
 	 * This usb_bus_get here is superfluous, because we receive
 	 * a notification if usb_bus is about to be removed.
 	 */
 	// usb_bus_get(ubus);
 	mbus->u_bus = ubus;
 	ubus->mon_bus = mbus;

 	rc = snprintf(name, NAMESZ, "%dt", ubus->busnum);
 	if (rc <= 0 || rc >= NAMESZ)
 		goto err_print_t;
 	d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_text);
 	if (d == NULL)
 		goto err_create_t;
 	mbus->dent_t = d;

 	rc = snprintf(name, NAMESZ, "%ds", ubus->busnum);
 	if (rc <= 0 || rc >= NAMESZ)
 		goto err_print_s;
 	d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_stat);
 	if (d == NULL)
 		goto err_create_s;
 	mbus->dent_s = d;

 	down(&mon_lock);
 	list_add_tail(&mbus->bus_link, &mon_buses);
 	up(&mon_lock);
 	return;

 err_create_s:
 err_print_s:
 	debugfs_remove(mbus->dent_t);
 err_create_t:
 err_print_t:
 	kfree(mbus);
 err_alloc:
 	return;
 }

 static int __init mon_init(void)
 {
 	struct usb_bus *ubus;
 	struct dentry *mondir;

 	mondir = debugfs_create_dir("usbmon", NULL);
 	if (IS_ERR(mondir)) {
 		printk(KERN_NOTICE TAG ": debugfs is not available\n");
 		return -ENODEV;
 	}
 	if (mondir == NULL) {
 		printk(KERN_NOTICE TAG ": unable to create usbmon directory\n");
 		return -ENODEV;
 	}
 	mon_dir = mondir;

 	if (usb_mon_register(&mon_ops_0) != 0) {
 		printk(KERN_NOTICE TAG ": unable to register with the core\n");
 		debugfs_remove(mondir);
 		return -ENODEV;
 	}
 	// MOD_INC_USE_COUNT(which_module?);

 	down(&usb_bus_list_lock);
 	list_for_each_entry (ubus, &usb_bus_list, bus_list) {
 		mon_bus_init(mondir, ubus);
 	}
 	up(&usb_bus_list_lock);
 	return 0;
 }

 static void __exit mon_exit(void)
 {
 	struct mon_bus *mbus;
 	struct list_head *p;

 	usb_mon_deregister();

 	down(&mon_lock);
 	while (!list_empty(&mon_buses)) {
 		p = mon_buses.next;
 		mbus = list_entry(p, struct mon_bus, bus_link);
 		list_del(p);

 		debugfs_remove(mbus->dent_t);
 		debugfs_remove(mbus->dent_s);

 		/*
 		 * This never happens, because the open/close paths in
 		 * file level maintain module use counters and so rmmod fails
 		 * before reaching here. However, better be safe...
 		 */
 		if (mbus->nreaders) {
 			printk(KERN_ERR TAG
 			    ": Outstanding opens (%d) on usb%d, leaking...\n",
 			    mbus->nreaders, mbus->u_bus->busnum);
 			atomic_set(&mbus->ref.refcount, 2);	/* Force leak */
 		}

 		mon_dissolve(mbus, mbus->u_bus);
 		kref_put(&mbus->ref, mon_bus_drop);
 	}
 	up(&mon_lock);

 	debugfs_remove(mon_dir);
 }

 module_init(mon_init);
 module_exit(mon_exit);

 MODULE_LICENSE("GPL");
	/*
	* The USB Monitor, inspired by Dave Harding's USBMon.
	*
	* mon_main.c: Main file, module initiation and exit, registrations, etc.
	*
	* Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/usb.h>
	#include <linux/debugfs.h>
	#include <linux/smp_lock.h>

	#include "usb_mon.h"
	#include "../core/hcd.h"

	static void mon_submit(struct usb_bus ubus, struct urb urb);
	static void mon_complete(struct usb_bus ubus, struct urb urb);
	static void mon_stop(struct mon_bus *mbus);
	static void mon_dissolve(struct mon_bus mbus, struct usb_bus ubus);
	static void mon_bus_drop(struct kref *r);
	static void mon_bus_init(struct dentry mondir, struct usb_bus ubus);

	DECLARE_MUTEX(mon_lock);

	static struct dentry mon_dir; / /dbg/usbmon */
	static LIST_HEAD(mon_buses); /* All buses we know: struct mon_bus */

	/*
	* Link a reader into the bus.
	*
	* This must be called with mon_lock taken because of mbus->ref.
	*/
	void mon_reader_add(struct mon_bus mbus, struct mon_reader r)
	{
	unsigned long flags;
	struct usb_bus *ubus;

	spin_lock_irqsave(&mbus->lock, flags);
	if (mbus->nreaders == 0) {
	ubus = mbus->u_bus;
	if (ubus->monitored) {
	/*
	* Something is really broken, refuse to go on and
	* possibly corrupt ops pointers or worse.
	*/
	printk(KERN_ERR TAG ": bus %d is already monitored\n",
	ubus->busnum);
	spin_unlock_irqrestore(&mbus->lock, flags);
	return;
	}
	ubus->monitored = 1;
	}
	mbus->nreaders++;
	list_add_tail(&r->r_link, &mbus->r_list);
	spin_unlock_irqrestore(&mbus->lock, flags);

	kref_get(&mbus->ref);
	}

	/*
	* Unlink reader from the bus.
	*
	* This is called with mon_lock taken, so we can decrement mbus->ref.
	*/
	void mon_reader_del(struct mon_bus mbus, struct mon_reader r)
	{
	unsigned long flags;

	spin_lock_irqsave(&mbus->lock, flags);
	list_del(&r->r_link);
	--mbus->nreaders;
	if (mbus->nreaders == 0)
	mon_stop(mbus);
	spin_unlock_irqrestore(&mbus->lock, flags);

	kref_put(&mbus->ref, mon_bus_drop);
	}

	/*
	*/
	static void mon_submit(struct usb_bus ubus, struct urb urb)
	{
	struct mon_bus *mbus;
	unsigned long flags;
	struct list_head *pos;
	struct mon_reader *r;

	mbus = ubus->mon_bus;
	if (mbus == NULL)
	goto out_unlocked;

	spin_lock_irqsave(&mbus->lock, flags);
	if (mbus->nreaders == 0)
	goto out_locked;

	list_for_each (pos, &mbus->r_list) {
	r = list_entry(pos, struct mon_reader, r_link);
	r->rnf_submit(r->r_data, urb);
	}

	spin_unlock_irqrestore(&mbus->lock, flags);
	return;

	out_locked:
	spin_unlock_irqrestore(&mbus->lock, flags);
	out_unlocked:
	return;
	}

	/*
	*/
	static void mon_submit_error(struct usb_bus ubus, struct urb urb, int err)
	{
	struct mon_bus *mbus;

	mbus = ubus->mon_bus;
	if (mbus == NULL)
	goto out_unlocked;

	/*
	* XXX Capture the error code and the 'E' event.
	*/

	return;

	out_unlocked:
	return;
	}

	/*
	*/
	static void mon_complete(struct usb_bus ubus, struct urb urb)
	{
	struct mon_bus *mbus;
	unsigned long flags;
	struct list_head *pos;
	struct mon_reader *r;

	mbus = ubus->mon_bus;
	if (mbus == NULL) {
	/*
	* This should not happen.
	* At this point we do not even know the bus number...
	*/
	printk(KERN_ERR TAG ": Null mon bus in URB, pipe 0x%x\n",
	urb->pipe);
	return;
	}

	spin_lock_irqsave(&mbus->lock, flags);
	list_for_each (pos, &mbus->r_list) {
	r = list_entry(pos, struct mon_reader, r_link);
	r->rnf_complete(r->r_data, urb);
	}
	spin_unlock_irqrestore(&mbus->lock, flags);
	}

	/* int (unlink_urb) (struct urb urb, int status); */

	/*
	* Stop monitoring.
	* Obviously this must be well locked, so no need to play with mb's.
	*/
	static void mon_stop(struct mon_bus *mbus)
	{
	struct usb_bus *ubus = mbus->u_bus;

	/*
	* A stop can be called for a dissolved mon_bus in case of
	* a reader staying across an rmmod foo_hcd.
	*/
	if (ubus != NULL) {
	ubus->monitored = 0;
	mb();
	}
	}

	/*
	* Add a USB bus (usually by a modprobe foo-hcd)
	*
	* This does not return an error code because the core cannot care less
	* if monitoring is not established.
	*/
	static void mon_bus_add(struct usb_bus *ubus)
	{
	mon_bus_init(mon_dir, ubus);
	}

	/*
	* Remove a USB bus (either from rmmod foo-hcd or from a hot-remove event).
	*/
	static void mon_bus_remove(struct usb_bus *ubus)
	{
	struct mon_bus *mbus = ubus->mon_bus;

	down(&mon_lock);
	list_del(&mbus->bus_link);
	debugfs_remove(mbus->dent_t);
	debugfs_remove(mbus->dent_s);

	mon_dissolve(mbus, ubus);
	kref_put(&mbus->ref, mon_bus_drop);
	up(&mon_lock);
	}

	/*
	* Ops
	*/
	static struct usb_mon_operations mon_ops_0 = {
	.urb_submit = mon_submit,
	.urb_submit_error = mon_submit_error,
	.urb_complete = mon_complete,
	.bus_add = mon_bus_add,
	.bus_remove = mon_bus_remove,
	};

	/*
	* Tear usb_bus and mon_bus apart.
	*/
	static void mon_dissolve(struct mon_bus mbus, struct usb_bus ubus)
	{

	/*
	* Never happens, but...
	*/
	if (ubus->monitored) {
	printk(KERN_ERR TAG ": bus %d is dissolved while monitored\n",
	ubus->busnum);
	ubus->monitored = 0;
	mb();
	}

	ubus->mon_bus = NULL;
	mbus->u_bus = NULL;
	mb();
	// usb_bus_put(ubus);
	}

	/*
	*/
	static void mon_bus_drop(struct kref *r)
	{
	struct mon_bus *mbus = container_of(r, struct mon_bus, ref);
	kfree(mbus);
	}

	/*
	* Initialize a bus for us:
	* - allocate mon_bus
	* - refcount USB bus struct
	* - link
	*/
	static void mon_bus_init(struct dentry mondir, struct usb_bus ubus)
	{
	struct dentry *d;
	struct mon_bus *mbus;
	enum { NAMESZ = 10 };
	char name[NAMESZ];
	int rc;

	if ((mbus = kmalloc(sizeof(struct mon_bus), GFP_KERNEL)) == NULL)
	goto err_alloc;
	memset(mbus, 0, sizeof(struct mon_bus));
	kref_init(&mbus->ref);
	spin_lock_init(&mbus->lock);
	INIT_LIST_HEAD(&mbus->r_list);

	/*
	* This usb_bus_get here is superfluous, because we receive
	* a notification if usb_bus is about to be removed.
	*/
	// usb_bus_get(ubus);
	mbus->u_bus = ubus;
	ubus->mon_bus = mbus;

	rc = snprintf(name, NAMESZ, "%dt", ubus->busnum);
	if (rc <= 0 \|\| rc >= NAMESZ)
	goto err_print_t;
	d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_text);
	if (d == NULL)
	goto err_create_t;
	mbus->dent_t = d;

	rc = snprintf(name, NAMESZ, "%ds", ubus->busnum);
	if (rc <= 0 \|\| rc >= NAMESZ)
	goto err_print_s;
	d = debugfs_create_file(name, 0600, mondir, mbus, &mon_fops_stat);
	if (d == NULL)
	goto err_create_s;
	mbus->dent_s = d;

	down(&mon_lock);
	list_add_tail(&mbus->bus_link, &mon_buses);
	up(&mon_lock);
	return;

	err_create_s:
	err_print_s:
	debugfs_remove(mbus->dent_t);
	err_create_t:
	err_print_t:
	kfree(mbus);
	err_alloc:
	return;
	}

	static int __init mon_init(void)
	{
	struct usb_bus *ubus;
	struct dentry *mondir;

	mondir = debugfs_create_dir("usbmon", NULL);
	if (IS_ERR(mondir)) {
	printk(KERN_NOTICE TAG ": debugfs is not available\n");
	return -ENODEV;
	}
	if (mondir == NULL) {
	printk(KERN_NOTICE TAG ": unable to create usbmon directory\n");
	return -ENODEV;
	}
	mon_dir = mondir;

	if (usb_mon_register(&mon_ops_0) != 0) {
	printk(KERN_NOTICE TAG ": unable to register with the core\n");
	debugfs_remove(mondir);
	return -ENODEV;
	}
	// MOD_INC_USE_COUNT(which_module?);

	down(&usb_bus_list_lock);
	list_for_each_entry (ubus, &usb_bus_list, bus_list) {
	mon_bus_init(mondir, ubus);
	}
	up(&usb_bus_list_lock);
	return 0;
	}

	static void __exit mon_exit(void)
	{
	struct mon_bus *mbus;
	struct list_head *p;

	usb_mon_deregister();

	down(&mon_lock);
	while (!list_empty(&mon_buses)) {
	p = mon_buses.next;
	mbus = list_entry(p, struct mon_bus, bus_link);
	list_del(p);

	debugfs_remove(mbus->dent_t);
	debugfs_remove(mbus->dent_s);

	/*
	* This never happens, because the open/close paths in
	* file level maintain module use counters and so rmmod fails
	* before reaching here. However, better be safe...
	*/
	if (mbus->nreaders) {
	printk(KERN_ERR TAG
	": Outstanding opens (%d) on usb%d, leaking...\n",
	mbus->nreaders, mbus->u_bus->busnum);
	atomic_set(&mbus->ref.refcount, 2); /* Force leak */
	}

	mon_dissolve(mbus, mbus->u_bus);
	kref_put(&mbus->ref, mon_bus_drop);
	}
	up(&mon_lock);

	debugfs_remove(mon_dir);
	}

	module_init(mon_init);
	module_exit(mon_exit);

	MODULE_LICENSE("GPL");