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13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15#include <linux/kernel.h>
16#include <linux/jffs2.h>
17#include <linux/mtd/mtd.h>
18#include <linux/completion.h>
19#include <linux/sched.h>
20#include <linux/freezer.h>
21#include <linux/kthread.h>
22#include "nodelist.h"
23
24
25static int jffs2_garbage_collect_thread(void *);
26
27void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c)
28{
29 assert_spin_locked(&c->erase_completion_lock);
30 if (c->gc_task && jffs2_thread_should_wake(c))
31 send_sig(SIGHUP, c->gc_task, 1);
32}
33
34
35int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c)
36{
37 struct task_struct *tsk;
38 int ret = 0;
39
40 BUG_ON(c->gc_task);
41
42 init_completion(&c->gc_thread_start);
43 init_completion(&c->gc_thread_exit);
44
45 tsk = kthread_run(jffs2_garbage_collect_thread, c, "jffs2_gcd_mtd%d", c->mtd->index);
46 if (IS_ERR(tsk)) {
47 pr_warn("fork failed for JFFS2 garbage collect thread: %ld\n",
48 -PTR_ERR(tsk));
49 complete(&c->gc_thread_exit);
50 ret = PTR_ERR(tsk);
51 } else {
52
53 jffs2_dbg(1, "Garbage collect thread is pid %d\n", tsk->pid);
54 wait_for_completion(&c->gc_thread_start);
55 ret = tsk->pid;
56 }
57
58 return ret;
59}
60
61void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c)
62{
63 int wait = 0;
64 spin_lock(&c->erase_completion_lock);
65 if (c->gc_task) {
66 jffs2_dbg(1, "Killing GC task %d\n", c->gc_task->pid);
67 send_sig(SIGKILL, c->gc_task, 1);
68 wait = 1;
69 }
70 spin_unlock(&c->erase_completion_lock);
71 if (wait)
72 wait_for_completion(&c->gc_thread_exit);
73}
74
75static int jffs2_garbage_collect_thread(void *_c)
76{
77 struct jffs2_sb_info *c = _c;
78 sigset_t hupmask;
79
80 siginitset(&hupmask, sigmask(SIGHUP));
81 allow_signal(SIGKILL);
82 allow_signal(SIGSTOP);
83 allow_signal(SIGCONT);
84 allow_signal(SIGHUP);
85
86 c->gc_task = current;
87 complete(&c->gc_thread_start);
88
89 set_user_nice(current, 10);
90
91 set_freezable();
92 for (;;) {
93 sigprocmask(SIG_UNBLOCK, &hupmask, NULL);
94 again:
95 spin_lock(&c->erase_completion_lock);
96 if (!jffs2_thread_should_wake(c)) {
97 set_current_state (TASK_INTERRUPTIBLE);
98 spin_unlock(&c->erase_completion_lock);
99 jffs2_dbg(1, "%s(): sleeping...\n", __func__);
100 schedule();
101 } else {
102 spin_unlock(&c->erase_completion_lock);
103 }
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113
114 schedule_timeout_interruptible(msecs_to_jiffies(50));
115
116 if (kthread_should_stop()) {
117 jffs2_dbg(1, "%s(): kthread_stop() called\n", __func__);
118 goto die;
119 }
120
121
122
123 while (signal_pending(current) || freezing(current)) {
124 siginfo_t info;
125 unsigned long signr;
126
127 if (try_to_freeze())
128 goto again;
129
130 signr = dequeue_signal_lock(current, ¤t->blocked, &info);
131
132 switch(signr) {
133 case SIGSTOP:
134 jffs2_dbg(1, "%s(): SIGSTOP received\n",
135 __func__);
136 set_current_state(TASK_STOPPED);
137 schedule();
138 break;
139
140 case SIGKILL:
141 jffs2_dbg(1, "%s(): SIGKILL received\n",
142 __func__);
143 goto die;
144
145 case SIGHUP:
146 jffs2_dbg(1, "%s(): SIGHUP received\n",
147 __func__);
148 break;
149 default:
150 jffs2_dbg(1, "%s(): signal %ld received\n",
151 __func__, signr);
152 }
153 }
154
155 sigprocmask(SIG_BLOCK, &hupmask, NULL);
156
157 jffs2_dbg(1, "%s(): pass\n", __func__);
158 if (jffs2_garbage_collect_pass(c) == -ENOSPC) {
159 pr_notice("No space for garbage collection. Aborting GC thread\n");
160 goto die;
161 }
162 }
163 die:
164 spin_lock(&c->erase_completion_lock);
165 c->gc_task = NULL;
166 spin_unlock(&c->erase_completion_lock);
167 complete_and_exit(&c->gc_thread_exit, 0);
168}
169