write in 30M

hc

2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc

 kernel/drivers/usb/misc/usblcd.c
..
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@@ -30,15 +30,11 @@
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 #define IOCTL_GET_DRV_VERSION	2
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-static DEFINE_MUTEX(lcd_mutex);
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 static const struct usb_device_id id_table[] = {
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 	{ .idVendor = 0x10D2, .match_flags = USB_DEVICE_ID_MATCH_VENDOR, },
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 	{ },
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 };
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 MODULE_DEVICE_TABLE(usb, id_table);
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-
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-static DEFINE_MUTEX(open_disc_mutex);
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-
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 struct usb_lcd {
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 	struct usb_device	*udev;			/* init: probe_lcd */
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@@ -84,40 +80,29 @@
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 	struct usb_interface *interface;
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 	int subminor, r;
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-	mutex_lock(&lcd_mutex);
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 	subminor = iminor(inode);
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 	interface = usb_find_interface(&lcd_driver, subminor);
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 	if (!interface) {
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-		mutex_unlock(&lcd_mutex);
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-		printk(KERN_ERR "USBLCD: %s - error, can't find device for minor %d\n",
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+		pr_err("USBLCD: %s - error, can't find device for minor %d\n",
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 		       __func__, subminor);
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 		return -ENODEV;
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 	}
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-	mutex_lock(&open_disc_mutex);
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 	dev = usb_get_intfdata(interface);
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-	if (!dev) {
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-		mutex_unlock(&open_disc_mutex);
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-		mutex_unlock(&lcd_mutex);
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-		return -ENODEV;
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-	}
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 	/* increment our usage count for the device */
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 	kref_get(&dev->kref);
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-	mutex_unlock(&open_disc_mutex);
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 	/* grab a power reference */
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 	r = usb_autopm_get_interface(interface);
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 	if (r < 0) {
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 		kref_put(&dev->kref, lcd_delete);
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-		mutex_unlock(&lcd_mutex);
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 		return r;
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 	}
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 	/* save our object in the file's private structure */
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 	file->private_data = dev;
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-	mutex_unlock(&lcd_mutex);
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 	return 0;
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 }
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@@ -186,14 +171,12 @@
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 	switch (cmd) {
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 	case IOCTL_GET_HARD_VERSION:
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-		mutex_lock(&lcd_mutex);
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 		bcdDevice = le16_to_cpu((dev->udev)->descriptor.bcdDevice);
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 		sprintf(buf, "%1d%1d.%1d%1d",
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 			(bcdDevice & 0xF000)>>12,
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 			(bcdDevice & 0xF00)>>8,
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 			(bcdDevice & 0xF0)>>4,
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 			(bcdDevice & 0xF));
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-		mutex_unlock(&lcd_mutex);
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 		if (copy_to_user((void __user *)arg, buf, strlen(buf)) != 0)
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 			return -EFAULT;
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 		break;
..
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@@ -204,7 +187,6 @@
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 		break;
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 	default:
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 		return -ENOTTY;
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-		break;
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 	}
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 	return 0;
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@@ -388,7 +370,6 @@
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 		/* something prevented us from registering this driver */
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 		dev_err(&interface->dev,
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 			"Not able to get a minor for this device.\n");
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-		usb_set_intfdata(interface, NULL);
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 		goto error;
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 	}
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..
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@@ -434,13 +415,8 @@
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 static void lcd_disconnect(struct usb_interface *interface)
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 {
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-	struct usb_lcd *dev;
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+	struct usb_lcd *dev = usb_get_intfdata(interface);
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 	int minor = interface->minor;
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-
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-	mutex_lock(&open_disc_mutex);
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-	dev = usb_get_intfdata(interface);
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-	usb_set_intfdata(interface, NULL);
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-	mutex_unlock(&open_disc_mutex);
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 	/* give back our minor */
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 	usb_deregister_dev(interface, &lcd_class);