[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / jffs2 / background.c

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright (C) 2001-2003 Red Hat, Inc.
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 * $Id: background.c,v 1.54 2005/05/20 21:37:12 gleixner Exp $
 *
 */

#include <linux/kernel.h>
#include <linux/jffs2.h>
#include <linux/mtd/mtd.h>
#include <linux/completion.h>
#include <linux/sched.h>
#include "nodelist.h"


static int jffs2_garbage_collect_thread(void *);

void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c)
{
	spin_lock(&c->erase_completion_lock);
        if (c->gc_task && jffs2_thread_should_wake(c))
                send_sig(SIGHUP, c->gc_task, 1);
	spin_unlock(&c->erase_completion_lock);
}

/* This must only ever be called when no GC thread is currently running */
int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c)
{
	pid_t pid;
	int ret = 0;

	if (c->gc_task)
		BUG();

	init_completion(&c->gc_thread_start);
	init_completion(&c->gc_thread_exit);

	pid = kernel_thread(jffs2_garbage_collect_thread, c, CLONE_FS|CLONE_FILES);
	if (pid < 0) {
		printk(KERN_WARNING "fork failed for JFFS2 garbage collect thread: %d\n", -pid);
		complete(&c->gc_thread_exit);
		ret = pid;
	} else {
		/* Wait for it... */
		D1(printk(KERN_DEBUG "JFFS2: Garbage collect thread is pid %d\n", pid));
		wait_for_completion(&c->gc_thread_start);
	}
 
	return ret;
}

void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c)
{
	int wait = 0;
	spin_lock(&c->erase_completion_lock);
	if (c->gc_task) {
		D1(printk(KERN_DEBUG "jffs2: Killing GC task %d\n", c->gc_task->pid));
		send_sig(SIGKILL, c->gc_task, 1);
		wait = 1;
	}
	spin_unlock(&c->erase_completion_lock);
	if (wait)
		wait_for_completion(&c->gc_thread_exit);
}

static int jffs2_garbage_collect_thread(void *_c)
{
	struct jffs2_sb_info *c = _c;

	daemonize("jffs2_gcd_mtd%d", c->mtd->index);
	allow_signal(SIGKILL);
	allow_signal(SIGSTOP);
	allow_signal(SIGCONT);

	c->gc_task = current;
	complete(&c->gc_thread_start);

	set_user_nice(current, 10);

	for (;;) {
		allow_signal(SIGHUP);

		if (!jffs2_thread_should_wake(c)) {
			set_current_state (TASK_INTERRUPTIBLE);
			D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread sleeping...\n"));
			/* Yes, there's a race here; we checked jffs2_thread_should_wake()
			   before setting current->state to TASK_INTERRUPTIBLE. But it doesn't
			   matter - We don't care if we miss a wakeup, because the GC thread
			   is only an optimisation anyway. */
			schedule();
		}

		if (try_to_freeze())
			continue;

		cond_resched();

		/* Put_super will send a SIGKILL and then wait on the sem. 
		 */
		while (signal_pending(current)) {
			siginfo_t info;
			unsigned long signr;

			signr = dequeue_signal_lock(current, &current->blocked, &info);

			switch(signr) {
			case SIGSTOP:
				D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGSTOP received.\n"));
				set_current_state(TASK_STOPPED);
				schedule();
				break;

			case SIGKILL:
				D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGKILL received.\n"));
				goto die;

			case SIGHUP:
				D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGHUP received.\n"));
				break;
			default:
				D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): signal %ld received\n", signr));
			}
		}
		/* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */
		disallow_signal(SIGHUP);

		D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n"));
		if (jffs2_garbage_collect_pass(c) == -ENOSPC) {
			printk(KERN_NOTICE "No space for garbage collection. Aborting GC thread\n");
			goto die;
		}
	}
 die:
	spin_lock(&c->erase_completion_lock);
	c->gc_task = NULL;
	spin_unlock(&c->erase_completion_lock);
	complete_and_exit(&c->gc_thread_exit, 0);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* JFFS2 -- Journalling Flash File System, Version 2.
	3	*
	4	* Copyright (C) 2001-2003 Red Hat, Inc.
	5	*
	6	* Created by David Woodhouse <dwmw2@infradead.org>
	7	*
	8	* For licensing information, see the file 'LICENCE' in this directory.
	9	*
e2d48b1a	10	* $Id: background.c,v 1.54 2005/05/20 21:37:12 gleixner Exp $
1da177e4 LT	11	*
	12	*/
	13
	14	#include <linux/kernel.h>
	15	#include <linux/jffs2.h>
	16	#include <linux/mtd/mtd.h>
	17	#include <linux/completion.h>
4e57b681	18	#include <linux/sched.h>
1da177e4 LT	19	#include "nodelist.h"
	20
	21
	22	static int jffs2_garbage_collect_thread(void *);
	23
	24	void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c)
	25	{
	26	spin_lock(&c->erase_completion_lock);
	27	if (c->gc_task && jffs2_thread_should_wake(c))
	28	send_sig(SIGHUP, c->gc_task, 1);
	29	spin_unlock(&c->erase_completion_lock);
	30	}
	31
	32	/* This must only ever be called when no GC thread is currently running */
	33	int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c)
	34	{
	35	pid_t pid;
	36	int ret = 0;
	37
	38	if (c->gc_task)
	39	BUG();
	40
fff7afd7	41	init_completion(&c->gc_thread_start);
1da177e4 LT	42	init_completion(&c->gc_thread_exit);
	43
	44	pid = kernel_thread(jffs2_garbage_collect_thread, c, CLONE_FS\|CLONE_FILES);
	45	if (pid < 0) {
	46	printk(KERN_WARNING "fork failed for JFFS2 garbage collect thread: %d\n", -pid);
	47	complete(&c->gc_thread_exit);
	48	ret = pid;
	49	} else {
	50	/* Wait for it... */
	51	D1(printk(KERN_DEBUG "JFFS2: Garbage collect thread is pid %d\n", pid));
fff7afd7	52	wait_for_completion(&c->gc_thread_start);
1da177e4 LT	53	}
	54
	55	return ret;
	56	}
	57
	58	void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c)
	59	{
e2d48b1a	60	int wait = 0;
1da177e4 LT	61	spin_lock(&c->erase_completion_lock);
	62	if (c->gc_task) {
	63	D1(printk(KERN_DEBUG "jffs2: Killing GC task %d\n", c->gc_task->pid));
	64	send_sig(SIGKILL, c->gc_task, 1);
e2d48b1a	65	wait = 1;
1da177e4 LT	66	}
1da177e4 LT	67	spin_unlock(&c->erase_completion_lock);
e2d48b1a TG	68	if (wait)
e2d48b1a TG	69	wait_for_completion(&c->gc_thread_exit);
1da177e4 LT	70	}
	71
	72	static int jffs2_garbage_collect_thread(void *_c)
	73	{
	74	struct jffs2_sb_info *c = _c;
	75
	76	daemonize("jffs2_gcd_mtd%d", c->mtd->index);
	77	allow_signal(SIGKILL);
	78	allow_signal(SIGSTOP);
	79	allow_signal(SIGCONT);
	80
	81	c->gc_task = current;
fff7afd7	82	complete(&c->gc_thread_start);
1da177e4 LT	83
	84	set_user_nice(current, 10);
	85
	86	for (;;) {
	87	allow_signal(SIGHUP);
	88
	89	if (!jffs2_thread_should_wake(c)) {
	90	set_current_state (TASK_INTERRUPTIBLE);
	91	D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread sleeping...\n"));
	92	/* Yes, there's a race here; we checked jffs2_thread_should_wake()
	93	before setting current->state to TASK_INTERRUPTIBLE. But it doesn't
	94	matter - We don't care if we miss a wakeup, because the GC thread
	95	is only an optimisation anyway. */
	96	schedule();
	97	}
	98
34f18a98	99	if (try_to_freeze())
1da177e4 LT	100	continue;
	101
	102	cond_resched();
	103
	104	/* Put_super will send a SIGKILL and then wait on the sem.
	105	*/
	106	while (signal_pending(current)) {
	107	siginfo_t info;
	108	unsigned long signr;
	109
	110	signr = dequeue_signal_lock(current, &current->blocked, &info);
	111
	112	switch(signr) {
	113	case SIGSTOP:
	114	D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGSTOP received.\n"));
	115	set_current_state(TASK_STOPPED);
	116	schedule();
	117	break;
	118
	119	case SIGKILL:
	120	D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGKILL received.\n"));
	121	goto die;
	122
	123	case SIGHUP:
	124	D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGHUP received.\n"));
	125	break;
	126	default:
	127	D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): signal %ld received\n", signr));
	128	}
	129	}
	130	/* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */
	131	disallow_signal(SIGHUP);
	132
	133	D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n"));
	134	if (jffs2_garbage_collect_pass(c) == -ENOSPC) {
	135	printk(KERN_NOTICE "No space for garbage collection. Aborting GC thread\n");
	136	goto die;
	137	}
	138	}
	139	die:
	140	spin_lock(&c->erase_completion_lock);
	141	c->gc_task = NULL;
	142	spin_unlock(&c->erase_completion_lock);
	143	complete_and_exit(&c->gc_thread_exit, 0);
	144	}