1 files changed, 117 insertions, 87 deletions

diff --git a/drivers/usb/core/file.c b/drivers/usb/core/file.c
index 37b13368c81..ea337a718cc 100644
--- a/drivers/usb/core/file.c
+++ b/drivers/usb/core/file.c
@@ -1,5 +1,5 @@
 /*
- * drivers/usb/file.c
+ * drivers/usb/core/file.c
  *
  * (C) Copyright Linus Torvalds 1999
  * (C) Copyright Johannes Erdfelt 1999-2001
@@ -8,86 +8,124 @@
  * (C) Copyright Deti Fliegl 1999 (new USB architecture)
  * (C) Copyright Randy Dunlap 2000
  * (C) Copyright David Brownell 2000-2001 (kernel hotplug, usb_device_id,
- 	more docs, etc)
+ *	more docs, etc)
  * (C) Copyright Yggdrasil Computing, Inc. 2000
  *     (usb_device_id matching changes by Adam J. Richter)
  * (C) Copyright Greg Kroah-Hartman 2002-2003
  *
  */
 
-#include <linux/config.h>
 #include <linux/module.h>
-#include <linux/spinlock.h>
 #include <linux/errno.h>
+#include <linux/rwsem.h>
+#include <linux/slab.h>
 #include <linux/usb.h>
 
 #include "usb.h"
 
 #define MAX_USB_MINORS	256
-static struct file_operations *usb_minors[MAX_USB_MINORS];
-static DEFINE_SPINLOCK(minor_lock);
+static const struct file_operations *usb_minors[MAX_USB_MINORS];
+static DECLARE_RWSEM(minor_rwsem);
 
-static int usb_open(struct inode * inode, struct file * file)
+static int usb_open(struct inode *inode, struct file *file)
 {
-	int minor = iminor(inode);
-	struct file_operations *c;
 	int err = -ENODEV;
-	struct file_operations *old_fops, *new_fops = NULL;
+	const struct file_operations *new_fops;
 
-	spin_lock (&minor_lock);
-	c = usb_minors[minor];
+	down_read(&minor_rwsem);
+	new_fops = fops_get(usb_minors[iminor(inode)]);
 
-	if (!c || !(new_fops = fops_get(c))) {
-		spin_unlock(&minor_lock);
-		return err;
-	}
-	spin_unlock(&minor_lock);
+	if (!new_fops)
+		goto done;
 
-	old_fops = file->f_op;
-	file->f_op = new_fops;
+	replace_fops(file, new_fops);
 	/* Curiouser and curiouser... NULL ->open() as "no device" ? */
 	if (file->f_op->open)
-		err = file->f_op->open(inode,file);
-	if (err) {
-		fops_put(file->f_op);
-		file->f_op = fops_get(old_fops);
-	}
-	fops_put(old_fops);
+		err = file->f_op->open(inode, file);
+ done:
+	up_read(&minor_rwsem);
 	return err;
 }
 
-static struct file_operations usb_fops = {
+static const struct file_operations usb_fops = {
 	.owner =	THIS_MODULE,
 	.open =		usb_open,
+	.llseek =	noop_llseek,
 };
 
-static struct class *usb_class;
+static struct usb_class {
+	struct kref kref;
+	struct class *class;
+} *usb_class;
 
-int usb_major_init(void)
+static char *usb_devnode(struct device *dev, umode_t *mode)
 {
-	int error;
+	struct usb_class_driver *drv;
 
-	error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
-	if (error) {
-		err("unable to get major %d for usb devices", USB_MAJOR);
-		goto out;
+	drv = dev_get_drvdata(dev);
+	if (!drv || !drv->devnode)
+		return NULL;
+	return drv->devnode(dev, mode);
+}
+
+static int init_usb_class(void)
+{
+	int result = 0;
+
+	if (usb_class != NULL) {
+		kref_get(&usb_class->kref);
+		goto exit;
 	}
 
-	usb_class = class_create(THIS_MODULE, "usb");
-	if (IS_ERR(usb_class)) {
-		error = PTR_ERR(usb_class);
-		err("class_create failed for usb devices");
-		unregister_chrdev(USB_MAJOR, "usb");
-		goto out;
+	usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
+	if (!usb_class) {
+		result = -ENOMEM;
+		goto exit;
 	}
 
-out:
+	kref_init(&usb_class->kref);
+	usb_class->class = class_create(THIS_MODULE, "usbmisc");
+	if (IS_ERR(usb_class->class)) {
+		result = PTR_ERR(usb_class->class);
+		printk(KERN_ERR "class_create failed for usb devices\n");
+		kfree(usb_class);
+		usb_class = NULL;
+		goto exit;
+	}
+	usb_class->class->devnode = usb_devnode;
+
+exit:
+	return result;
+}
+
+static void release_usb_class(struct kref *kref)
+{
+	/* Ok, we cheat as we know we only have one usb_class */
+	class_destroy(usb_class->class);
+	kfree(usb_class);
+	usb_class = NULL;
+}
+
+static void destroy_usb_class(void)
+{
+	if (usb_class)
+		kref_put(&usb_class->kref, release_usb_class);
+}
+
+int usb_major_init(void)
+{
+	int error;
+
+	error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
+	if (error)
+		printk(KERN_ERR "Unable to get major %d for usb devices\n",
+		       USB_MAJOR);
+
 	return error;
 }
 
 void usb_major_cleanup(void)
 {
-	class_destroy(usb_class);
 	unregister_chrdev(USB_MAJOR, "usb");
 }
 
@@ -107,70 +145,71 @@ void usb_major_cleanup(void)
  * usb_deregister_dev() must be called when the driver is done with
  * the minor numbers given out by this function.
  *
- * Returns -EINVAL if something bad happens with trying to register a
+ * Return: -EINVAL if something bad happens with trying to register a
  * device, and 0 on success.
  */
 int usb_register_dev(struct usb_interface *intf,
 		     struct usb_class_driver *class_driver)
 {
-	int retval = -EINVAL;
+	int retval;
 	int minor_base = class_driver->minor_base;
-	int minor = 0;
-	char name[BUS_ID_SIZE];
+	int minor;
+	char name[20];
 	char *temp;
 
 #ifdef CONFIG_USB_DYNAMIC_MINORS
-	/* 
+	/*
 	 * We don't care what the device tries to start at, we want to start
 	 * at zero to pack the devices into the smallest available space with
 	 * no holes in the minor range.
 	 */
 	minor_base = 0;
 #endif
-	intf->minor = -1;
-
-	dbg ("looking for a minor, starting at %d", minor_base);
 
 	if (class_driver->fops == NULL)
-		goto exit;
+		return -EINVAL;
+	if (intf->minor >= 0)
+		return -EADDRINUSE;
+
+	retval = init_usb_class();
+	if (retval)
+		return retval;
 
-	spin_lock (&minor_lock);
+	dev_dbg(&intf->dev, "looking for a minor, starting at %d\n", minor_base);
+
+	down_write(&minor_rwsem);
 	for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
 		if (usb_minors[minor])
 			continue;
 
 		usb_minors[minor] = class_driver->fops;
-
-		retval = 0;
+		intf->minor = minor;
 		break;
 	}
-	spin_unlock (&minor_lock);
-
-	if (retval)
-		goto exit;
-
-	intf->minor = minor;
+	up_write(&minor_rwsem);
+	if (intf->minor < 0)
+		return -EXFULL;
 
 	/* create a usb class device for this usb interface */
-	snprintf(name, BUS_ID_SIZE, class_driver->name, minor - minor_base);
+	snprintf(name, sizeof(name), class_driver->name, minor - minor_base);
 	temp = strrchr(name, '/');
-	if (temp && (temp[1] != 0x00))
+	if (temp && (temp[1] != '\0'))
 		++temp;
 	else
 		temp = name;
-	intf->class_dev = class_device_create(usb_class, NULL,
-					      MKDEV(USB_MAJOR, minor),
-					      &intf->dev, "%s", temp);
-	if (IS_ERR(intf->class_dev)) {
-		spin_lock (&minor_lock);
-		usb_minors[intf->minor] = NULL;
-		spin_unlock (&minor_lock);
-		retval = PTR_ERR(intf->class_dev);
+	intf->usb_dev = device_create(usb_class->class, &intf->dev,
+				      MKDEV(USB_MAJOR, minor), class_driver,
+				      "%s", temp);
+	if (IS_ERR(intf->usb_dev)) {
+		down_write(&minor_rwsem);
+		usb_minors[minor] = NULL;
+		intf->minor = -1;
+		up_write(&minor_rwsem);
+		retval = PTR_ERR(intf->usb_dev);
 	}
-exit:
 	return retval;
 }
-EXPORT_SYMBOL(usb_register_dev);
+EXPORT_SYMBOL_GPL(usb_register_dev);
 
 /**
  * usb_deregister_dev - deregister a USB device's dynamic minor.
@@ -189,27 +228,18 @@ EXPORT_SYMBOL(usb_register_dev);
 void usb_deregister_dev(struct usb_interface *intf,
 			struct usb_class_driver *class_driver)
 {
-	int minor_base = class_driver->minor_base;
-	char name[BUS_ID_SIZE];
-
-#ifdef CONFIG_USB_DYNAMIC_MINORS
-	minor_base = 0;
-#endif
-
 	if (intf->minor == -1)
 		return;
 
-	dbg ("removing %d minor", intf->minor);
+	dev_dbg(&intf->dev, "removing %d minor\n", intf->minor);
 
-	spin_lock (&minor_lock);
+	down_write(&minor_rwsem);
 	usb_minors[intf->minor] = NULL;
-	spin_unlock (&minor_lock);
+	up_write(&minor_rwsem);
 
-	snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);
-	class_device_destroy(usb_class, MKDEV(USB_MAJOR, intf->minor));
-	intf->class_dev = NULL;
+	device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
+	intf->usb_dev = NULL;
 	intf->minor = -1;
+	destroy_usb_class();
 }
-EXPORT_SYMBOL(usb_deregister_dev);
-
-
+EXPORT_SYMBOL_GPL(usb_deregister_dev);