Viewing file:  background.c (6.17 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright (C) 2001 Red Hat, Inc.
*
* Created by David Woodhouse <dwmw2@cambridge.redhat.com>
*
* The original JFFS, from which the design for JFFS2 was derived,
* was designed and implemented by Axis Communications AB.
*
* The contents of this file are subject to the Red Hat eCos Public
* License Version 1.1 (the "Licence"); you may not use this file
* except in compliance with the Licence. You may obtain a copy of
* the Licence at http://www.redhat.com/
*
* Software distributed under the Licence is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.
* See the Licence for the specific language governing rights and
* limitations under the Licence.
*
* The Original Code is JFFS2 - Journalling Flash File System, version 2
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU General Public License version 2 (the "GPL"), in
* which case the provisions of the GPL are applicable instead of the
* above. If you wish to allow the use of your version of this file
* only under the terms of the GPL and not to allow others to use your
* version of this file under the RHEPL, indicate your decision by
* deleting the provisions above and replace them with the notice and
* other provisions required by the GPL. If you do not delete the
* provisions above, a recipient may use your version of this file
* under either the RHEPL or the GPL.
*
* $Id: background.c,v 1.16 2001/10/08 09:22:38 dwmw2 Exp $
*
*/
#define __KERNEL_SYSCALLS__
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/unistd.h>
#include <linux/jffs2.h>
#include <linux/mtd/mtd.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include "nodelist.h"
static int jffs2_garbage_collect_thread(void *);
static int thread_should_wake(struct jffs2_sb_info *c);
void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c)
{
spin_lock_bh(&c->erase_completion_lock);
if (c->gc_task && thread_should_wake(c))
send_sig(SIGHUP, c->gc_task, 1);
spin_unlock_bh(&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_MUTEX_LOCKED(&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));
down(&c->gc_thread_start);
}
return ret;
}
void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c)
{
spin_lock_bh(&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);
}
spin_unlock_bh(&c->erase_completion_lock);
wait_for_completion(&c->gc_thread_exit);
}
static int jffs2_garbage_collect_thread(void *_c)
{
struct jffs2_sb_info *c = _c;
daemonize();
current->tty = NULL;
c->gc_task = current;
up(&c->gc_thread_start);
sprintf(current->comm, "jffs2_gcd_mtd%d", c->mtd->index);
/* FIXME in the 2.2 backport */
current->nice = 10;
for (;;) {
spin_lock_irq(¤t->sigmask_lock);
siginitsetinv (¤t->blocked, sigmask(SIGHUP) | sigmask(SIGKILL) | sigmask(SIGSTOP) | sigmask(SIGCONT));
recalc_sigpending(current);
spin_unlock_irq(¤t->sigmask_lock);
if (!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 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 (current->need_resched)
schedule();
/* Put_super will send a SIGKILL and then wait on the sem.
*/
while (signal_pending(current)) {
siginfo_t info;
unsigned long signr;
spin_lock_irq(¤t->sigmask_lock);
signr = dequeue_signal(¤t->blocked, &info);
spin_unlock_irq(¤t->sigmask_lock);
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"));
spin_lock_bh(&c->erase_completion_lock);
c->gc_task = NULL;
spin_unlock_bh(&c->erase_completion_lock);
complete_and_exit(&c->gc_thread_exit, 0);
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. */
spin_lock_irq(¤t->sigmask_lock);
siginitsetinv (¤t->blocked, sigmask(SIGKILL) | sigmask(SIGSTOP) | sigmask(SIGCONT));
recalc_sigpending(current);
spin_unlock_irq(¤t->sigmask_lock);
D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n"));
jffs2_garbage_collect_pass(c);
}
}
static int thread_should_wake(struct jffs2_sb_info *c)
{
D1(printk(KERN_DEBUG "thread_should_wake(): nr_free_blocks %d, nr_erasing_blocks %d, dirty_size 0x%x\n",
c->nr_free_blocks, c->nr_erasing_blocks, c->dirty_size));
if (c->nr_free_blocks + c->nr_erasing_blocks < JFFS2_RESERVED_BLOCKS_GCTRIGGER &&
c->dirty_size > c->sector_size)
return 1;
else
return 0;
}
|