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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 | * | |
10 | * $Id: background.c,v 1.50 2004/11/16 20:36:10 dwmw2 Exp $ | |
11 | * | |
12 | */ | |
13 | ||
14 | #include <linux/kernel.h> | |
15 | #include <linux/jffs2.h> | |
16 | #include <linux/mtd/mtd.h> | |
17 | #include <linux/completion.h> | |
18 | #include "nodelist.h" | |
19 | ||
20 | ||
21 | static int jffs2_garbage_collect_thread(void *); | |
22 | ||
23 | void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c) | |
24 | { | |
25 | spin_lock(&c->erase_completion_lock); | |
26 | if (c->gc_task && jffs2_thread_should_wake(c)) | |
27 | send_sig(SIGHUP, c->gc_task, 1); | |
28 | spin_unlock(&c->erase_completion_lock); | |
29 | } | |
30 | ||
31 | /* This must only ever be called when no GC thread is currently running */ | |
32 | int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c) | |
33 | { | |
34 | pid_t pid; | |
35 | int ret = 0; | |
36 | ||
37 | if (c->gc_task) | |
38 | BUG(); | |
39 | ||
40 | init_MUTEX_LOCKED(&c->gc_thread_start); | |
41 | init_completion(&c->gc_thread_exit); | |
42 | ||
43 | pid = kernel_thread(jffs2_garbage_collect_thread, c, CLONE_FS|CLONE_FILES); | |
44 | if (pid < 0) { | |
45 | printk(KERN_WARNING "fork failed for JFFS2 garbage collect thread: %d\n", -pid); | |
46 | complete(&c->gc_thread_exit); | |
47 | ret = pid; | |
48 | } else { | |
49 | /* Wait for it... */ | |
50 | D1(printk(KERN_DEBUG "JFFS2: Garbage collect thread is pid %d\n", pid)); | |
51 | down(&c->gc_thread_start); | |
52 | } | |
53 | ||
54 | return ret; | |
55 | } | |
56 | ||
57 | void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c) | |
58 | { | |
59 | spin_lock(&c->erase_completion_lock); | |
60 | if (c->gc_task) { | |
61 | D1(printk(KERN_DEBUG "jffs2: Killing GC task %d\n", c->gc_task->pid)); | |
62 | send_sig(SIGKILL, c->gc_task, 1); | |
63 | } | |
64 | spin_unlock(&c->erase_completion_lock); | |
65 | wait_for_completion(&c->gc_thread_exit); | |
66 | } | |
67 | ||
68 | static int jffs2_garbage_collect_thread(void *_c) | |
69 | { | |
70 | struct jffs2_sb_info *c = _c; | |
71 | ||
72 | daemonize("jffs2_gcd_mtd%d", c->mtd->index); | |
73 | allow_signal(SIGKILL); | |
74 | allow_signal(SIGSTOP); | |
75 | allow_signal(SIGCONT); | |
76 | ||
77 | c->gc_task = current; | |
78 | up(&c->gc_thread_start); | |
79 | ||
80 | set_user_nice(current, 10); | |
81 | ||
82 | for (;;) { | |
83 | allow_signal(SIGHUP); | |
84 | ||
85 | if (!jffs2_thread_should_wake(c)) { | |
86 | set_current_state (TASK_INTERRUPTIBLE); | |
87 | D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread sleeping...\n")); | |
88 | /* Yes, there's a race here; we checked jffs2_thread_should_wake() | |
89 | before setting current->state to TASK_INTERRUPTIBLE. But it doesn't | |
90 | matter - We don't care if we miss a wakeup, because the GC thread | |
91 | is only an optimisation anyway. */ | |
92 | schedule(); | |
93 | } | |
94 | ||
95 | if (try_to_freeze(0)) | |
96 | continue; | |
97 | ||
98 | cond_resched(); | |
99 | ||
100 | /* Put_super will send a SIGKILL and then wait on the sem. | |
101 | */ | |
102 | while (signal_pending(current)) { | |
103 | siginfo_t info; | |
104 | unsigned long signr; | |
105 | ||
106 | signr = dequeue_signal_lock(current, ¤t->blocked, &info); | |
107 | ||
108 | switch(signr) { | |
109 | case SIGSTOP: | |
110 | D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGSTOP received.\n")); | |
111 | set_current_state(TASK_STOPPED); | |
112 | schedule(); | |
113 | break; | |
114 | ||
115 | case SIGKILL: | |
116 | D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGKILL received.\n")); | |
117 | goto die; | |
118 | ||
119 | case SIGHUP: | |
120 | D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGHUP received.\n")); | |
121 | break; | |
122 | default: | |
123 | D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): signal %ld received\n", signr)); | |
124 | } | |
125 | } | |
126 | /* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */ | |
127 | disallow_signal(SIGHUP); | |
128 | ||
129 | D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n")); | |
130 | if (jffs2_garbage_collect_pass(c) == -ENOSPC) { | |
131 | printk(KERN_NOTICE "No space for garbage collection. Aborting GC thread\n"); | |
132 | goto die; | |
133 | } | |
134 | } | |
135 | die: | |
136 | spin_lock(&c->erase_completion_lock); | |
137 | c->gc_task = NULL; | |
138 | spin_unlock(&c->erase_completion_lock); | |
139 | complete_and_exit(&c->gc_thread_exit, 0); | |
140 | } |