mirror of
https://github.com/torvalds/linux.git
synced 2024-12-02 00:51:44 +00:00
ffed60971f
Commit 4a2a8a2cce ("usbfs: private mutex for open, release, and
remove") is now obsolete. The commit was created back when we had
to handle both usbfs device nodes and the old usbdevfs filesystem
(/proc/bus/usb/), but usbdevfs no longer exists.
This means there's no longer any need to hold a mutex during two
separate removal operations (and thus during an entire notifier chain
call). Furthermore, the one remaining remove/release pair doesn't
race with open thanks to the synchronization provided by the device
model core in bus_find_device(). Remove and release don't race with
each other because they both run with the device lock held.
The upshot is that usbfs_mutex isn't needed any more. This patch
removes it entirely.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
69 lines
1.7 KiB
C
69 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* All the USB notify logic
|
|
*
|
|
* (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
|
|
*
|
|
* notifier functions originally based on those in kernel/sys.c
|
|
* but fixed up to not be so broken.
|
|
*
|
|
* Released under the GPLv2 only.
|
|
*/
|
|
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/export.h>
|
|
#include <linux/notifier.h>
|
|
#include <linux/usb.h>
|
|
#include <linux/mutex.h>
|
|
#include "usb.h"
|
|
|
|
static BLOCKING_NOTIFIER_HEAD(usb_notifier_list);
|
|
|
|
/**
|
|
* usb_register_notify - register a notifier callback whenever a usb change happens
|
|
* @nb: pointer to the notifier block for the callback events.
|
|
*
|
|
* These changes are either USB devices or busses being added or removed.
|
|
*/
|
|
void usb_register_notify(struct notifier_block *nb)
|
|
{
|
|
blocking_notifier_chain_register(&usb_notifier_list, nb);
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_register_notify);
|
|
|
|
/**
|
|
* usb_unregister_notify - unregister a notifier callback
|
|
* @nb: pointer to the notifier block for the callback events.
|
|
*
|
|
* usb_register_notify() must have been previously called for this function
|
|
* to work properly.
|
|
*/
|
|
void usb_unregister_notify(struct notifier_block *nb)
|
|
{
|
|
blocking_notifier_chain_unregister(&usb_notifier_list, nb);
|
|
}
|
|
EXPORT_SYMBOL_GPL(usb_unregister_notify);
|
|
|
|
|
|
void usb_notify_add_device(struct usb_device *udev)
|
|
{
|
|
blocking_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev);
|
|
}
|
|
|
|
void usb_notify_remove_device(struct usb_device *udev)
|
|
{
|
|
blocking_notifier_call_chain(&usb_notifier_list,
|
|
USB_DEVICE_REMOVE, udev);
|
|
}
|
|
|
|
void usb_notify_add_bus(struct usb_bus *ubus)
|
|
{
|
|
blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus);
|
|
}
|
|
|
|
void usb_notify_remove_bus(struct usb_bus *ubus)
|
|
{
|
|
blocking_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus);
|
|
}
|