ed206ec9ab
usbled has a race where show methods for attributes in sysfs can follow a NULL pointer during disconnect. The correct ordering fixes it. Signed-off-by: Oliver Neukum <oneukum@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
190 lines
4.4 KiB
C
190 lines
4.4 KiB
C
/*
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* USB LED driver - 1.1
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*
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* Copyright (C) 2004 Greg Kroah-Hartman (greg@kroah.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/usb.h>
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#define DRIVER_AUTHOR "Greg Kroah-Hartman, greg@kroah.com"
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#define DRIVER_DESC "USB LED Driver"
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#define VENDOR_ID 0x0fc5
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#define PRODUCT_ID 0x1223
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/* table of devices that work with this driver */
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static struct usb_device_id id_table [] = {
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{ USB_DEVICE(VENDOR_ID, PRODUCT_ID) },
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{ },
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};
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MODULE_DEVICE_TABLE (usb, id_table);
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struct usb_led {
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struct usb_device * udev;
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unsigned char blue;
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unsigned char red;
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unsigned char green;
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};
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#define BLUE 0x04
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#define RED 0x02
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#define GREEN 0x01
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static void change_color(struct usb_led *led)
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{
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int retval;
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unsigned char color = 0x07;
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unsigned char *buffer;
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buffer = kmalloc(8, GFP_KERNEL);
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if (!buffer) {
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dev_err(&led->udev->dev, "out of memory\n");
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return;
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}
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if (led->blue)
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color &= ~(BLUE);
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if (led->red)
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color &= ~(RED);
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if (led->green)
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color &= ~(GREEN);
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dev_dbg(&led->udev->dev,
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"blue = %d, red = %d, green = %d, color = %.2x\n",
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led->blue, led->red, led->green, color);
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retval = usb_control_msg(led->udev,
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usb_sndctrlpipe(led->udev, 0),
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0x12,
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0xc8,
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(0x02 * 0x100) + 0x0a,
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(0x00 * 0x100) + color,
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buffer,
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8,
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2000);
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if (retval)
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dev_dbg(&led->udev->dev, "retval = %d\n", retval);
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kfree(buffer);
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}
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#define show_set(value) \
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static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \
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{ \
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struct usb_interface *intf = to_usb_interface(dev); \
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struct usb_led *led = usb_get_intfdata(intf); \
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\
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return sprintf(buf, "%d\n", led->value); \
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} \
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static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \
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{ \
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struct usb_interface *intf = to_usb_interface(dev); \
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struct usb_led *led = usb_get_intfdata(intf); \
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int temp = simple_strtoul(buf, NULL, 10); \
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\
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led->value = temp; \
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change_color(led); \
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return count; \
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} \
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static DEVICE_ATTR(value, S_IWUGO | S_IRUGO, show_##value, set_##value);
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show_set(blue);
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show_set(red);
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show_set(green);
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static int led_probe(struct usb_interface *interface, const struct usb_device_id *id)
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{
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struct usb_device *udev = interface_to_usbdev(interface);
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struct usb_led *dev = NULL;
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int retval = -ENOMEM;
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dev = kzalloc(sizeof(struct usb_led), GFP_KERNEL);
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if (dev == NULL) {
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dev_err(&interface->dev, "Out of memory\n");
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goto error_mem;
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}
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dev->udev = usb_get_dev(udev);
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usb_set_intfdata (interface, dev);
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retval = device_create_file(&interface->dev, &dev_attr_blue);
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if (retval)
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goto error;
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retval = device_create_file(&interface->dev, &dev_attr_red);
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if (retval)
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goto error;
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retval = device_create_file(&interface->dev, &dev_attr_green);
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if (retval)
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goto error;
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dev_info(&interface->dev, "USB LED device now attached\n");
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return 0;
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error:
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device_remove_file(&interface->dev, &dev_attr_blue);
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device_remove_file(&interface->dev, &dev_attr_red);
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device_remove_file(&interface->dev, &dev_attr_green);
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usb_set_intfdata (interface, NULL);
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usb_put_dev(dev->udev);
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kfree(dev);
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error_mem:
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return retval;
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}
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static void led_disconnect(struct usb_interface *interface)
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{
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struct usb_led *dev;
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dev = usb_get_intfdata (interface);
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device_remove_file(&interface->dev, &dev_attr_blue);
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device_remove_file(&interface->dev, &dev_attr_red);
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device_remove_file(&interface->dev, &dev_attr_green);
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/* first remove the files, then set the pointer to NULL */
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usb_set_intfdata (interface, NULL);
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usb_put_dev(dev->udev);
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kfree(dev);
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dev_info(&interface->dev, "USB LED now disconnected\n");
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}
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static struct usb_driver led_driver = {
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.name = "usbled",
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.probe = led_probe,
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.disconnect = led_disconnect,
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.id_table = id_table,
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};
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static int __init usb_led_init(void)
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{
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int retval = 0;
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retval = usb_register(&led_driver);
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if (retval)
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err("usb_register failed. Error number %d", retval);
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return retval;
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}
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static void __exit usb_led_exit(void)
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{
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usb_deregister(&led_driver);
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}
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module_init (usb_led_init);
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module_exit (usb_led_exit);
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MODULE_AUTHOR(DRIVER_AUTHOR);
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MODULE_DESCRIPTION(DRIVER_DESC);
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MODULE_LICENSE("GPL");
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