freebsd-skq/sys/dev/usb/usb_util.c
Hans Petter Selasky 64cb5e2a26 Resolve deadlock between device_detach() and usbd_do_request_flags()
by reviving the SX control request lock and refining which lock
protects the common scratch area in "struct usb_device".

The SX control request lock was removed by r246759 because it caused a
lock order reversal with the USB enumeration lock inside
usbd_transfer_setup() as a function of r246616. It was thought that
reducing the number of locks would resolve the LOR, but because some
USB device drivers use usbd_do_request_flags() inside callback
functions, like in taskqueues, a deadlock may occur when these are
drained from device_detach(). By restoring the SX control request
lock usbd_do_request_flags() is allowed to complete its execution
when a USB device driver is detaching. By using the SX control request
lock to protect the scratch area, the LOR introduced by r246616 is
also resolved.

Bump the FreeBSD version while at it to force recompilation of all USB
kernel modules.

Found by:	avos@
MFC after:	1 week
2016-09-05 15:35:58 +00:00

224 lines
6.0 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.
*/
#ifdef USB_GLOBAL_INCLUDE_FILE
#include USB_GLOBAL_INCLUDE_FILE
#else
#include <sys/stdint.h>
#include <sys/stddef.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <sys/unistd.h>
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>
#include <dev/usb/usb.h>
#include <dev/usb/usbdi.h>
#include <dev/usb/usbdi_util.h>
#include <dev/usb/usb_core.h>
#include <dev/usb/usb_util.h>
#include <dev/usb/usb_process.h>
#include <dev/usb/usb_device.h>
#include <dev/usb/usb_request.h>
#include <dev/usb/usb_busdma.h>
#include <dev/usb/usb_controller.h>
#include <dev/usb/usb_bus.h>
#endif /* USB_GLOBAL_INCLUDE_FILE */
/*------------------------------------------------------------------------*
* device_set_usb_desc
*
* This function can be called at probe or attach to set the USB
* device supplied textual description for the given device.
*------------------------------------------------------------------------*/
void
device_set_usb_desc(device_t dev)
{
struct usb_attach_arg *uaa;
struct usb_device *udev;
struct usb_interface *iface;
char *temp_p;
usb_error_t err;
uint8_t do_unlock;
if (dev == NULL) {
/* should not happen */
return;
}
uaa = device_get_ivars(dev);
if (uaa == NULL) {
/* can happen if called at the wrong time */
return;
}
udev = uaa->device;
iface = uaa->iface;
if ((iface == NULL) ||
(iface->idesc == NULL) ||
(iface->idesc->iInterface == 0)) {
err = USB_ERR_INVAL;
} else {
err = 0;
}
/* Protect scratch area */
do_unlock = usbd_ctrl_lock(udev);
temp_p = (char *)udev->scratch.data;
if (err == 0) {
/* try to get the interface string ! */
err = usbd_req_get_string_any(udev, NULL, temp_p,
sizeof(udev->scratch.data),
iface->idesc->iInterface);
}
if (err != 0) {
/* use default description */
usb_devinfo(udev, temp_p,
sizeof(udev->scratch.data));
}
if (do_unlock)
usbd_ctrl_unlock(udev);
device_set_desc_copy(dev, temp_p);
device_printf(dev, "<%s> on %s\n", temp_p,
device_get_nameunit(udev->bus->bdev));
}
/*------------------------------------------------------------------------*
* usb_pause_mtx - factored out code
*
* This function will delay the code by the passed number of system
* ticks. The passed mutex "mtx" will be dropped while waiting, if
* "mtx" is different from NULL.
*------------------------------------------------------------------------*/
void
usb_pause_mtx(struct mtx *mtx, int timo)
{
if (mtx != NULL)
mtx_unlock(mtx);
/*
* Add one tick to the timeout so that we don't return too
* early! Note that pause() will assert that the passed
* timeout is positive and non-zero!
*/
pause("USBWAIT", timo + 1);
if (mtx != NULL)
mtx_lock(mtx);
}
/*------------------------------------------------------------------------*
* usb_printbcd
*
* This function will print the version number "bcd" to the string
* pointed to by "p" having a maximum length of "p_len" bytes
* including the terminating zero.
*------------------------------------------------------------------------*/
void
usb_printbcd(char *p, uint16_t p_len, uint16_t bcd)
{
if (snprintf(p, p_len, "%x.%02x", bcd >> 8, bcd & 0xff)) {
/* ignore any errors */
}
}
/*------------------------------------------------------------------------*
* usb_trim_spaces
*
* This function removes spaces at the beginning and the end of the string
* pointed to by the "p" argument.
*------------------------------------------------------------------------*/
void
usb_trim_spaces(char *p)
{
char *q;
char *e;
if (p == NULL)
return;
q = e = p;
while (*q == ' ') /* skip leading spaces */
q++;
while ((*p = *q++)) /* copy string */
if (*p++ != ' ') /* remember last non-space */
e = p;
*e = 0; /* kill trailing spaces */
}
/*------------------------------------------------------------------------*
* usb_make_str_desc - convert an ASCII string into a UNICODE string
*------------------------------------------------------------------------*/
uint8_t
usb_make_str_desc(void *ptr, uint16_t max_len, const char *s)
{
struct usb_string_descriptor *p = ptr;
uint8_t totlen;
int j;
if (max_len < 2) {
/* invalid length */
return (0);
}
max_len = ((max_len / 2) - 1);
j = strlen(s);
if (j < 0) {
j = 0;
}
if (j > 126) {
j = 126;
}
if (max_len > j) {
max_len = j;
}
totlen = (max_len + 1) * 2;
p->bLength = totlen;
p->bDescriptorType = UDESC_STRING;
while (max_len--) {
USETW2(p->bString[max_len], 0, s[max_len]);
}
return (totlen);
}