freebsd-nq/sys/dev/usb/usb_process.h
Hans Petter Selasky d008478e28 Try to resolve a possible deadlock when detaching USB devices which
create character devices. The deadlock can happen if an application is
issuing IOCTLs which require USB refcounting, at the same time the USB
device is detaching.

There is already a counter in place in the USB device structure to
detect this situation, but it was not always checked ahead of invoking
functions that might destroy character devices, like detach, set
configuration, set alternate interface or detach active kernel driver.

Reported by:	Daniel O'Connor <doconnor@gsoft.com.au>
MFC after:	1 week
2014-03-20 13:53:24 +00:00

92 lines
2.9 KiB
C

/* $FreeBSD$ */
/*-
* Copyright (c) 2008 Hans Petter Selasky. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _USB_PROCESS_H_
#define _USB_PROCESS_H_
#ifndef USB_GLOBAL_INCLUDE_FILE
#include <sys/interrupt.h>
#include <sys/priority.h>
#include <sys/runq.h>
#endif
/* defines */
#define USB_PRI_HIGH PI_SWI(SWI_NET)
#define USB_PRI_MED PI_SWI(SWI_CAMBIO)
#define USB_PROC_WAIT_TIMEOUT 2
#define USB_PROC_WAIT_DRAIN 1
#define USB_PROC_WAIT_NORMAL 0
/* structure prototypes */
struct usb_proc_msg;
struct usb_device;
/*
* The following structure defines the USB process.
*/
struct usb_process {
TAILQ_HEAD(, usb_proc_msg) up_qhead;
struct cv up_cv;
struct cv up_drain;
#if (__FreeBSD_version >= 800000)
struct thread *up_ptr;
#else
struct proc *up_ptr;
#endif
struct thread *up_curtd;
struct mtx *up_mtx;
usb_size_t up_msg_num;
uint8_t up_prio;
uint8_t up_gone;
uint8_t up_msleep;
uint8_t up_csleep;
uint8_t up_dsleep;
};
/* prototypes */
uint8_t usb_proc_is_gone(struct usb_process *up);
int usb_proc_create(struct usb_process *up, struct mtx *p_mtx,
const char *pmesg, uint8_t prio);
void usb_proc_drain(struct usb_process *up);
void usb_proc_mwait(struct usb_process *up, void *pm0, void *pm1);
void usb_proc_free(struct usb_process *up);
void *usb_proc_msignal(struct usb_process *up, void *pm0, void *pm1);
void usb_proc_rewakeup(struct usb_process *up);
int usb_proc_is_called_from(struct usb_process *up);
void usb_proc_explore_mwait(struct usb_device *, void *, void *);
void *usb_proc_explore_msignal(struct usb_device *, void *, void *);
void usb_proc_explore_lock(struct usb_device *);
void usb_proc_explore_unlock(struct usb_device *);
#endif /* _USB_PROCESS_H_ */