![Christoph Lameter](/assets/img/avatar_default.png)
1. Establish a simple API for process freezing defined in linux/include/sched.h: frozen(process) Check for frozen process freezing(process) Check if a process is being frozen freeze(process) Tell a process to freeze (go to refrigerator) thaw_process(process) Restart process frozen_process(process) Process is frozen now 2. Remove all references to PF_FREEZE and PF_FROZEN from all kernel sources except sched.h 3. Fix numerous locations where try_to_freeze is manually done by a driver 4. Remove the argument that is no longer necessary from two function calls. 5. Some whitespace cleanup 6. Clear potential race in refrigerator (provides an open window of PF_FREEZE cleared before setting PF_FROZEN, recalc_sigpending does not check PF_FROZEN). This patch does not address the problem of freeze_processes() violating the rule that a task may only modify its own flags by setting PF_FREEZE. This is not clean in an SMP environment. freeze(process) is therefore not SMP safe! Signed-off-by: Christoph Lameter <christoph@lameter.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
502 lines
12 KiB
C
502 lines
12 KiB
C
/*********************************************************************
|
|
*
|
|
* sir_kthread.c: dedicated thread to process scheduled
|
|
* sir device setup requests
|
|
*
|
|
* Copyright (c) 2002 Martin Diehl
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License as
|
|
* published by the Free Software Foundation; either version 2 of
|
|
* the License, or (at your option) any later version.
|
|
*
|
|
********************************************************************/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/version.h>
|
|
#include <linux/init.h>
|
|
#include <linux/smp_lock.h>
|
|
#include <linux/completion.h>
|
|
#include <linux/delay.h>
|
|
|
|
#include <net/irda/irda.h>
|
|
|
|
#include "sir-dev.h"
|
|
|
|
/**************************************************************************
|
|
*
|
|
* kIrDAd kernel thread and config state machine
|
|
*
|
|
*/
|
|
|
|
struct irda_request_queue {
|
|
struct list_head request_list;
|
|
spinlock_t lock;
|
|
task_t *thread;
|
|
struct completion exit;
|
|
wait_queue_head_t kick, done;
|
|
atomic_t num_pending;
|
|
};
|
|
|
|
static struct irda_request_queue irda_rq_queue;
|
|
|
|
static int irda_queue_request(struct irda_request *rq)
|
|
{
|
|
int ret = 0;
|
|
unsigned long flags;
|
|
|
|
if (!test_and_set_bit(0, &rq->pending)) {
|
|
spin_lock_irqsave(&irda_rq_queue.lock, flags);
|
|
list_add_tail(&rq->lh_request, &irda_rq_queue.request_list);
|
|
wake_up(&irda_rq_queue.kick);
|
|
atomic_inc(&irda_rq_queue.num_pending);
|
|
spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
|
|
ret = 1;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void irda_request_timer(unsigned long data)
|
|
{
|
|
struct irda_request *rq = (struct irda_request *)data;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&irda_rq_queue.lock, flags);
|
|
list_add_tail(&rq->lh_request, &irda_rq_queue.request_list);
|
|
wake_up(&irda_rq_queue.kick);
|
|
spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
|
|
}
|
|
|
|
static int irda_queue_delayed_request(struct irda_request *rq, unsigned long delay)
|
|
{
|
|
int ret = 0;
|
|
struct timer_list *timer = &rq->timer;
|
|
|
|
if (!test_and_set_bit(0, &rq->pending)) {
|
|
timer->expires = jiffies + delay;
|
|
timer->function = irda_request_timer;
|
|
timer->data = (unsigned long)rq;
|
|
atomic_inc(&irda_rq_queue.num_pending);
|
|
add_timer(timer);
|
|
ret = 1;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void run_irda_queue(void)
|
|
{
|
|
unsigned long flags;
|
|
struct list_head *entry, *tmp;
|
|
struct irda_request *rq;
|
|
|
|
spin_lock_irqsave(&irda_rq_queue.lock, flags);
|
|
list_for_each_safe(entry, tmp, &irda_rq_queue.request_list) {
|
|
rq = list_entry(entry, struct irda_request, lh_request);
|
|
list_del_init(entry);
|
|
spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
|
|
|
|
clear_bit(0, &rq->pending);
|
|
rq->func(rq->data);
|
|
|
|
if (atomic_dec_and_test(&irda_rq_queue.num_pending))
|
|
wake_up(&irda_rq_queue.done);
|
|
|
|
spin_lock_irqsave(&irda_rq_queue.lock, flags);
|
|
}
|
|
spin_unlock_irqrestore(&irda_rq_queue.lock, flags);
|
|
}
|
|
|
|
static int irda_thread(void *startup)
|
|
{
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
|
|
daemonize("kIrDAd");
|
|
|
|
irda_rq_queue.thread = current;
|
|
|
|
complete((struct completion *)startup);
|
|
|
|
while (irda_rq_queue.thread != NULL) {
|
|
|
|
/* We use TASK_INTERRUPTIBLE, rather than
|
|
* TASK_UNINTERRUPTIBLE. Andrew Morton made this
|
|
* change ; he told me that it is safe, because "signal
|
|
* blocking is now handled in daemonize()", he added
|
|
* that the problem is that "uninterruptible sleep
|
|
* contributes to load average", making user worry.
|
|
* Jean II */
|
|
set_task_state(current, TASK_INTERRUPTIBLE);
|
|
add_wait_queue(&irda_rq_queue.kick, &wait);
|
|
if (list_empty(&irda_rq_queue.request_list))
|
|
schedule();
|
|
else
|
|
__set_task_state(current, TASK_RUNNING);
|
|
remove_wait_queue(&irda_rq_queue.kick, &wait);
|
|
|
|
/* make swsusp happy with our thread */
|
|
try_to_freeze();
|
|
|
|
run_irda_queue();
|
|
}
|
|
|
|
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,35)
|
|
reparent_to_init();
|
|
#endif
|
|
complete_and_exit(&irda_rq_queue.exit, 0);
|
|
/* never reached */
|
|
return 0;
|
|
}
|
|
|
|
|
|
static void flush_irda_queue(void)
|
|
{
|
|
if (atomic_read(&irda_rq_queue.num_pending)) {
|
|
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
|
|
if (!list_empty(&irda_rq_queue.request_list))
|
|
run_irda_queue();
|
|
|
|
set_task_state(current, TASK_UNINTERRUPTIBLE);
|
|
add_wait_queue(&irda_rq_queue.done, &wait);
|
|
if (atomic_read(&irda_rq_queue.num_pending))
|
|
schedule();
|
|
else
|
|
__set_task_state(current, TASK_RUNNING);
|
|
remove_wait_queue(&irda_rq_queue.done, &wait);
|
|
}
|
|
}
|
|
|
|
/* substate handler of the config-fsm to handle the cases where we want
|
|
* to wait for transmit completion before changing the port configuration
|
|
*/
|
|
|
|
static int irda_tx_complete_fsm(struct sir_dev *dev)
|
|
{
|
|
struct sir_fsm *fsm = &dev->fsm;
|
|
unsigned next_state, delay;
|
|
unsigned bytes_left;
|
|
|
|
do {
|
|
next_state = fsm->substate; /* default: stay in current substate */
|
|
delay = 0;
|
|
|
|
switch(fsm->substate) {
|
|
|
|
case SIRDEV_STATE_WAIT_XMIT:
|
|
if (dev->drv->chars_in_buffer)
|
|
bytes_left = dev->drv->chars_in_buffer(dev);
|
|
else
|
|
bytes_left = 0;
|
|
if (!bytes_left) {
|
|
next_state = SIRDEV_STATE_WAIT_UNTIL_SENT;
|
|
break;
|
|
}
|
|
|
|
if (dev->speed > 115200)
|
|
delay = (bytes_left*8*10000) / (dev->speed/100);
|
|
else if (dev->speed > 0)
|
|
delay = (bytes_left*10*10000) / (dev->speed/100);
|
|
else
|
|
delay = 0;
|
|
/* expected delay (usec) until remaining bytes are sent */
|
|
if (delay < 100) {
|
|
udelay(delay);
|
|
delay = 0;
|
|
break;
|
|
}
|
|
/* sleep some longer delay (msec) */
|
|
delay = (delay+999) / 1000;
|
|
break;
|
|
|
|
case SIRDEV_STATE_WAIT_UNTIL_SENT:
|
|
/* block until underlaying hardware buffer are empty */
|
|
if (dev->drv->wait_until_sent)
|
|
dev->drv->wait_until_sent(dev);
|
|
next_state = SIRDEV_STATE_TX_DONE;
|
|
break;
|
|
|
|
case SIRDEV_STATE_TX_DONE:
|
|
return 0;
|
|
|
|
default:
|
|
IRDA_ERROR("%s - undefined state\n", __FUNCTION__);
|
|
return -EINVAL;
|
|
}
|
|
fsm->substate = next_state;
|
|
} while (delay == 0);
|
|
return delay;
|
|
}
|
|
|
|
/*
|
|
* Function irda_config_fsm
|
|
*
|
|
* State machine to handle the configuration of the device (and attached dongle, if any).
|
|
* This handler is scheduled for execution in kIrDAd context, so we can sleep.
|
|
* however, kIrDAd is shared by all sir_dev devices so we better don't sleep there too
|
|
* long. Instead, for longer delays we start a timer to reschedule us later.
|
|
* On entry, fsm->sem is always locked and the netdev xmit queue stopped.
|
|
* Both must be unlocked/restarted on completion - but only on final exit.
|
|
*/
|
|
|
|
static void irda_config_fsm(void *data)
|
|
{
|
|
struct sir_dev *dev = data;
|
|
struct sir_fsm *fsm = &dev->fsm;
|
|
int next_state;
|
|
int ret = -1;
|
|
unsigned delay;
|
|
|
|
IRDA_DEBUG(2, "%s(), <%ld>\n", __FUNCTION__, jiffies);
|
|
|
|
do {
|
|
IRDA_DEBUG(3, "%s - state=0x%04x / substate=0x%04x\n",
|
|
__FUNCTION__, fsm->state, fsm->substate);
|
|
|
|
next_state = fsm->state;
|
|
delay = 0;
|
|
|
|
switch(fsm->state) {
|
|
|
|
case SIRDEV_STATE_DONGLE_OPEN:
|
|
if (dev->dongle_drv != NULL) {
|
|
ret = sirdev_put_dongle(dev);
|
|
if (ret) {
|
|
fsm->result = -EINVAL;
|
|
next_state = SIRDEV_STATE_ERROR;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Initialize dongle */
|
|
ret = sirdev_get_dongle(dev, fsm->param);
|
|
if (ret) {
|
|
fsm->result = ret;
|
|
next_state = SIRDEV_STATE_ERROR;
|
|
break;
|
|
}
|
|
|
|
/* Dongles are powered through the modem control lines which
|
|
* were just set during open. Before resetting, let's wait for
|
|
* the power to stabilize. This is what some dongle drivers did
|
|
* in open before, while others didn't - should be safe anyway.
|
|
*/
|
|
|
|
delay = 50;
|
|
fsm->substate = SIRDEV_STATE_DONGLE_RESET;
|
|
next_state = SIRDEV_STATE_DONGLE_RESET;
|
|
|
|
fsm->param = 9600;
|
|
|
|
break;
|
|
|
|
case SIRDEV_STATE_DONGLE_CLOSE:
|
|
/* shouldn't we just treat this as success=? */
|
|
if (dev->dongle_drv == NULL) {
|
|
fsm->result = -EINVAL;
|
|
next_state = SIRDEV_STATE_ERROR;
|
|
break;
|
|
}
|
|
|
|
ret = sirdev_put_dongle(dev);
|
|
if (ret) {
|
|
fsm->result = ret;
|
|
next_state = SIRDEV_STATE_ERROR;
|
|
break;
|
|
}
|
|
next_state = SIRDEV_STATE_DONE;
|
|
break;
|
|
|
|
case SIRDEV_STATE_SET_DTR_RTS:
|
|
ret = sirdev_set_dtr_rts(dev,
|
|
(fsm->param&0x02) ? TRUE : FALSE,
|
|
(fsm->param&0x01) ? TRUE : FALSE);
|
|
next_state = SIRDEV_STATE_DONE;
|
|
break;
|
|
|
|
case SIRDEV_STATE_SET_SPEED:
|
|
fsm->substate = SIRDEV_STATE_WAIT_XMIT;
|
|
next_state = SIRDEV_STATE_DONGLE_CHECK;
|
|
break;
|
|
|
|
case SIRDEV_STATE_DONGLE_CHECK:
|
|
ret = irda_tx_complete_fsm(dev);
|
|
if (ret < 0) {
|
|
fsm->result = ret;
|
|
next_state = SIRDEV_STATE_ERROR;
|
|
break;
|
|
}
|
|
if ((delay=ret) != 0)
|
|
break;
|
|
|
|
if (dev->dongle_drv) {
|
|
fsm->substate = SIRDEV_STATE_DONGLE_RESET;
|
|
next_state = SIRDEV_STATE_DONGLE_RESET;
|
|
}
|
|
else {
|
|
dev->speed = fsm->param;
|
|
next_state = SIRDEV_STATE_PORT_SPEED;
|
|
}
|
|
break;
|
|
|
|
case SIRDEV_STATE_DONGLE_RESET:
|
|
if (dev->dongle_drv->reset) {
|
|
ret = dev->dongle_drv->reset(dev);
|
|
if (ret < 0) {
|
|
fsm->result = ret;
|
|
next_state = SIRDEV_STATE_ERROR;
|
|
break;
|
|
}
|
|
}
|
|
else
|
|
ret = 0;
|
|
if ((delay=ret) == 0) {
|
|
/* set serial port according to dongle default speed */
|
|
if (dev->drv->set_speed)
|
|
dev->drv->set_speed(dev, dev->speed);
|
|
fsm->substate = SIRDEV_STATE_DONGLE_SPEED;
|
|
next_state = SIRDEV_STATE_DONGLE_SPEED;
|
|
}
|
|
break;
|
|
|
|
case SIRDEV_STATE_DONGLE_SPEED:
|
|
if (dev->dongle_drv->reset) {
|
|
ret = dev->dongle_drv->set_speed(dev, fsm->param);
|
|
if (ret < 0) {
|
|
fsm->result = ret;
|
|
next_state = SIRDEV_STATE_ERROR;
|
|
break;
|
|
}
|
|
}
|
|
else
|
|
ret = 0;
|
|
if ((delay=ret) == 0)
|
|
next_state = SIRDEV_STATE_PORT_SPEED;
|
|
break;
|
|
|
|
case SIRDEV_STATE_PORT_SPEED:
|
|
/* Finally we are ready to change the serial port speed */
|
|
if (dev->drv->set_speed)
|
|
dev->drv->set_speed(dev, dev->speed);
|
|
dev->new_speed = 0;
|
|
next_state = SIRDEV_STATE_DONE;
|
|
break;
|
|
|
|
case SIRDEV_STATE_DONE:
|
|
/* Signal network layer so it can send more frames */
|
|
netif_wake_queue(dev->netdev);
|
|
next_state = SIRDEV_STATE_COMPLETE;
|
|
break;
|
|
|
|
default:
|
|
IRDA_ERROR("%s - undefined state\n", __FUNCTION__);
|
|
fsm->result = -EINVAL;
|
|
/* fall thru */
|
|
|
|
case SIRDEV_STATE_ERROR:
|
|
IRDA_ERROR("%s - error: %d\n", __FUNCTION__, fsm->result);
|
|
|
|
#if 0 /* don't enable this before we have netdev->tx_timeout to recover */
|
|
netif_stop_queue(dev->netdev);
|
|
#else
|
|
netif_wake_queue(dev->netdev);
|
|
#endif
|
|
/* fall thru */
|
|
|
|
case SIRDEV_STATE_COMPLETE:
|
|
/* config change finished, so we are not busy any longer */
|
|
sirdev_enable_rx(dev);
|
|
up(&fsm->sem);
|
|
return;
|
|
}
|
|
fsm->state = next_state;
|
|
} while(!delay);
|
|
|
|
irda_queue_delayed_request(&fsm->rq, msecs_to_jiffies(delay));
|
|
}
|
|
|
|
/* schedule some device configuration task for execution by kIrDAd
|
|
* on behalf of the above state machine.
|
|
* can be called from process or interrupt/tasklet context.
|
|
*/
|
|
|
|
int sirdev_schedule_request(struct sir_dev *dev, int initial_state, unsigned param)
|
|
{
|
|
struct sir_fsm *fsm = &dev->fsm;
|
|
int xmit_was_down;
|
|
|
|
IRDA_DEBUG(2, "%s - state=0x%04x / param=%u\n", __FUNCTION__, initial_state, param);
|
|
|
|
if (down_trylock(&fsm->sem)) {
|
|
if (in_interrupt() || in_atomic() || irqs_disabled()) {
|
|
IRDA_DEBUG(1, "%s(), state machine busy!\n", __FUNCTION__);
|
|
return -EWOULDBLOCK;
|
|
} else
|
|
down(&fsm->sem);
|
|
}
|
|
|
|
if (fsm->state == SIRDEV_STATE_DEAD) {
|
|
/* race with sirdev_close should never happen */
|
|
IRDA_ERROR("%s(), instance staled!\n", __FUNCTION__);
|
|
up(&fsm->sem);
|
|
return -ESTALE; /* or better EPIPE? */
|
|
}
|
|
|
|
xmit_was_down = netif_queue_stopped(dev->netdev);
|
|
netif_stop_queue(dev->netdev);
|
|
atomic_set(&dev->enable_rx, 0);
|
|
|
|
fsm->state = initial_state;
|
|
fsm->param = param;
|
|
fsm->result = 0;
|
|
|
|
INIT_LIST_HEAD(&fsm->rq.lh_request);
|
|
fsm->rq.pending = 0;
|
|
fsm->rq.func = irda_config_fsm;
|
|
fsm->rq.data = dev;
|
|
|
|
if (!irda_queue_request(&fsm->rq)) { /* returns 0 on error! */
|
|
atomic_set(&dev->enable_rx, 1);
|
|
if (!xmit_was_down)
|
|
netif_wake_queue(dev->netdev);
|
|
up(&fsm->sem);
|
|
return -EAGAIN;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int __init irda_thread_create(void)
|
|
{
|
|
struct completion startup;
|
|
int pid;
|
|
|
|
spin_lock_init(&irda_rq_queue.lock);
|
|
irda_rq_queue.thread = NULL;
|
|
INIT_LIST_HEAD(&irda_rq_queue.request_list);
|
|
init_waitqueue_head(&irda_rq_queue.kick);
|
|
init_waitqueue_head(&irda_rq_queue.done);
|
|
atomic_set(&irda_rq_queue.num_pending, 0);
|
|
|
|
init_completion(&startup);
|
|
pid = kernel_thread(irda_thread, &startup, CLONE_FS|CLONE_FILES);
|
|
if (pid <= 0)
|
|
return -EAGAIN;
|
|
else
|
|
wait_for_completion(&startup);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void __exit irda_thread_join(void)
|
|
{
|
|
if (irda_rq_queue.thread) {
|
|
flush_irda_queue();
|
|
init_completion(&irda_rq_queue.exit);
|
|
irda_rq_queue.thread = NULL;
|
|
wake_up(&irda_rq_queue.kick);
|
|
wait_for_completion(&irda_rq_queue.exit);
|
|
}
|
|
}
|
|
|