usbmon: Add class for binary interface

Add a class which allows for an easier integration with udev.

This code was originally written by Paolo Abeni, and arrived to my tree
as a part of big patch to add binary API on December 18. As I understand,
Paolo always meant the class to be a part of the whole thing. This is his
udev rule to go along with the patch:

KERNEL=="usbmon[0-9]*", NAME="usbmon%n", MODE="0440",OWNER="root",GROUP="bin"

Signed-off-by: Pete Zaitcev <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/mon/mon_bin.c

···
  * This is a binary format reader.
  *
  * Copyright (C) 2006 Paolo Abeni ([e-mail])
- * Copyright (C) 2006 Pete Zaitcev ([e-mail])
+ * Copyright (C) 2006,2007 Pete Zaitcev ([e-mail])
  */
 
 #include <linux/kernel.h>
···
 
 #define MON_RING_EMPTY(rp)	((rp)->b_cnt == 0)
 
+static struct class *mon_bin_class;
 static dev_t mon_bin_dev0;
 static struct cdev mon_bin_cdev;
 
···
 		free_page((unsigned long) map[n].ptr);
 }
 
+int mon_bin_add(struct mon_bus *mbus, const struct usb_bus *ubus)
+{
+	struct device *dev;
+	unsigned minor = ubus? ubus->busnum: 0;
+
+	if (minor >= MON_BIN_MAX_MINOR)
+		return 0;
+
+	dev = device_create(mon_bin_class, ubus? ubus->controller: NULL,
+			MKDEV(MAJOR(mon_bin_dev0), minor), "usbmon%d", minor);
+	if (IS_ERR(dev))
+		return 0;
+
+	mbus->classdev = dev;
+	return 1;
+}
+
+void mon_bin_del(struct mon_bus *mbus)
+{
+	device_destroy(mon_bin_class, mbus->classdev->devt);
+}
+
 int __init mon_bin_init(void)
 {
 	int rc;
+
+	mon_bin_class = class_create(THIS_MODULE, "usbmon");
+	if (IS_ERR(mon_bin_class)) {
+		rc = PTR_ERR(mon_bin_class);
+		goto err_class;
+	}
 
 	rc = alloc_chrdev_region(&mon_bin_dev0, 0, MON_BIN_MAX_MINOR, "usbmon");
 	if (rc < 0)
···
 err_add:
 	unregister_chrdev_region(mon_bin_dev0, MON_BIN_MAX_MINOR);
 err_dev:
+	class_destroy(mon_bin_class);
+err_class:
 	return rc;
 }
 
···
 {
 	cdev_del(&mon_bin_cdev);
 	unregister_chrdev_region(mon_bin_dev0, MON_BIN_MAX_MINOR);
+	class_destroy(mon_bin_class);
 }

drivers/usb/mon/mon_main.c

···
 	list_del(&mbus->bus_link);
 	if (mbus->text_inited)
 		mon_text_del(mbus);
+	if (mbus->bin_inited)
+		mon_bin_del(mbus);
 
 	mon_dissolve(mbus, ubus);
 	kref_put(&mbus->ref, mon_bus_drop);
···
 	mbus->u_bus = ubus;
 	ubus->mon_bus = mbus;
 
-	mbus->text_inited = mon_text_add(mbus, ubus->busnum);
-	// mon_bin_add(...)
+	mbus->text_inited = mon_text_add(mbus, ubus);
+	mbus->bin_inited = mon_bin_add(mbus, ubus);
 
 	mutex_lock(&mon_lock);
 	list_add_tail(&mbus->bus_link, &mon_buses);
···
 	spin_lock_init(&mbus->lock);
 	INIT_LIST_HEAD(&mbus->r_list);
 
-	mbus->text_inited = mon_text_add(mbus, 0);
-	// mbus->bin_inited = mon_bin_add(mbus, 0);
+	mbus->text_inited = mon_text_add(mbus, NULL);
+	mbus->bin_inited = mon_bin_add(mbus, NULL);
 }
 
 /*
···
 
 		if (mbus->text_inited)
 			mon_text_del(mbus);
+		if (mbus->bin_inited)
+			mon_bin_del(mbus);
 
 		/*
 		 * This never happens, because the open/close paths in
···
 	mbus = &mon_bus0;
 	if (mbus->text_inited)
 		mon_text_del(mbus);
+	if (mbus->bin_inited)
+		mon_bin_del(mbus);
 
 	mutex_unlock(&mon_lock);
 

drivers/usb/mon/mon_text.c

···
 	.release =	mon_text_release,
 };
 
-int mon_text_add(struct mon_bus *mbus, int busnum)
+int mon_text_add(struct mon_bus *mbus, const struct usb_bus *ubus)
 {
 	struct dentry *d;
 	enum { NAMESZ = 10 };
 	char name[NAMESZ];
+	int busnum = ubus? ubus->busnum: 0;
 	int rc;
 
-	rc = snprintf(name, NAMESZ, "%dt", busnum);
-	if (rc <= 0 || rc >= NAMESZ)
-		goto err_print_t;
-	d = debugfs_create_file(name, 0600, mon_dir, mbus, &mon_fops_text_t);
-	if (d == NULL)
-		goto err_create_t;
-	mbus->dent_t = d;
+	if (ubus != NULL) {
+		rc = snprintf(name, NAMESZ, "%dt", busnum);
+		if (rc <= 0 || rc >= NAMESZ)
+			goto err_print_t;
+		d = debugfs_create_file(name, 0600, mon_dir, mbus,
+							     &mon_fops_text_t);
+		if (d == NULL)
+			goto err_create_t;
+		mbus->dent_t = d;
+	}
 
 	rc = snprintf(name, NAMESZ, "%du", busnum);
 	if (rc <= 0 || rc >= NAMESZ)
···
 	mbus->dent_u = NULL;
 err_create_u:
 err_print_u:
-	debugfs_remove(mbus->dent_t);
-	mbus->dent_t = NULL;
+	if (ubus != NULL) {
+		debugfs_remove(mbus->dent_t);
+		mbus->dent_t = NULL;
+	}
 err_create_t:
 err_print_t:
 	return 0;
···
 void mon_text_del(struct mon_bus *mbus)
 {
 	debugfs_remove(mbus->dent_u);
-	debugfs_remove(mbus->dent_t);
+	if (mbus->dent_t != NULL)
+		debugfs_remove(mbus->dent_t);
 	debugfs_remove(mbus->dent_s);
 }
 

drivers/usb/mon/usb_mon.h

···
 	struct usb_bus *u_bus;
 
 	int text_inited;
+	int bin_inited;
 	struct dentry *dent_s;		/* Debugging file */
 	struct dentry *dent_t;		/* Text interface file */
 	struct dentry *dent_u;		/* Second text interface file */
+	struct device *classdev;	/* Device in usbmon class */
 
 	/* Ref */
 	int nreaders;			/* Under mon_lock AND mbus->lock */
···
 
 struct mon_bus *mon_bus_lookup(unsigned int num);
 
-int /*bool*/ mon_text_add(struct mon_bus *mbus, int busnum);
+int /*bool*/ mon_text_add(struct mon_bus *mbus, const struct usb_bus *ubus);
 void mon_text_del(struct mon_bus *mbus);
-// void mon_bin_add(struct mon_bus *);
+int /*bool*/ mon_bin_add(struct mon_bus *mbus, const struct usb_bus *ubus);
+void mon_bin_del(struct mon_bus *mbus);
 
 int __init mon_text_init(void);
 void mon_text_exit(void);