2 * JFFS2 -- Journalling Flash File System, Version 2.
4 * Copyright (C) 2001-2003 Red Hat, Inc.
6 * Created by David Woodhouse <dwmw2@infradead.org>
8 * For licensing information, see the file 'LICENCE' in this directory.
10 * $Id: background.c,v 1.54 2005/05/20 21:37:12 gleixner Exp $
14 #include <linux/kernel.h>
15 #include <linux/jffs2.h>
16 #include <linux/mtd/mtd.h>
17 #include <linux/completion.h>
18 #include <linux/sched.h>
19 #include <linux/freezer.h>
23 static int jffs2_garbage_collect_thread(void *);
25 void jffs2_garbage_collect_trigger(struct jffs2_sb_info
*c
)
27 spin_lock(&c
->erase_completion_lock
);
28 if (c
->gc_task
&& jffs2_thread_should_wake(c
))
29 send_sig(SIGHUP
, c
->gc_task
, 1);
30 spin_unlock(&c
->erase_completion_lock
);
33 /* This must only ever be called when no GC thread is currently running */
34 int jffs2_start_garbage_collect_thread(struct jffs2_sb_info
*c
)
41 init_completion(&c
->gc_thread_start
);
42 init_completion(&c
->gc_thread_exit
);
44 pid
= kernel_thread(jffs2_garbage_collect_thread
, c
, CLONE_FS
|CLONE_FILES
);
46 printk(KERN_WARNING
"fork failed for JFFS2 garbage collect thread: %d\n", -pid
);
47 complete(&c
->gc_thread_exit
);
51 D1(printk(KERN_DEBUG
"JFFS2: Garbage collect thread is pid %d\n", pid
));
52 wait_for_completion(&c
->gc_thread_start
);
58 void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info
*c
)
61 spin_lock(&c
->erase_completion_lock
);
63 D1(printk(KERN_DEBUG
"jffs2: Killing GC task %d\n", c
->gc_task
->pid
));
64 send_sig(SIGKILL
, c
->gc_task
, 1);
67 spin_unlock(&c
->erase_completion_lock
);
69 wait_for_completion(&c
->gc_thread_exit
);
72 static int jffs2_garbage_collect_thread(void *_c
)
74 struct jffs2_sb_info
*c
= _c
;
76 daemonize("jffs2_gcd_mtd%d", c
->mtd
->index
);
77 allow_signal(SIGKILL
);
78 allow_signal(SIGSTOP
);
79 allow_signal(SIGCONT
);
82 complete(&c
->gc_thread_start
);
84 set_user_nice(current
, 10);
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. */
102 /* This thread is purely an optimisation. But if it runs when
103 other things could be running, it actually makes things a
104 lot worse. Use yield() and put it at the back of the runqueue
105 every time. Especially during boot, pulling an inode in
106 with read_inode() is much preferable to having the GC thread
110 /* Put_super will send a SIGKILL and then wait on the sem.
112 while (signal_pending(current
)) {
116 signr
= dequeue_signal_lock(current
, ¤t
->blocked
, &info
);
120 D1(printk(KERN_DEBUG
"jffs2_garbage_collect_thread(): SIGSTOP received.\n"));
121 set_current_state(TASK_STOPPED
);
126 D1(printk(KERN_DEBUG
"jffs2_garbage_collect_thread(): SIGKILL received.\n"));
130 D1(printk(KERN_DEBUG
"jffs2_garbage_collect_thread(): SIGHUP received.\n"));
133 D1(printk(KERN_DEBUG
"jffs2_garbage_collect_thread(): signal %ld received\n", signr
));
136 /* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */
137 disallow_signal(SIGHUP
);
139 D1(printk(KERN_DEBUG
"jffs2_garbage_collect_thread(): pass\n"));
140 if (jffs2_garbage_collect_pass(c
) == -ENOSPC
) {
141 printk(KERN_NOTICE
"No space for garbage collection. Aborting GC thread\n");
146 spin_lock(&c
->erase_completion_lock
);
148 spin_unlock(&c
->erase_completion_lock
);
149 complete_and_exit(&c
->gc_thread_exit
, 0);