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165 lines
4.2 KiB
165 lines
4.2 KiB
/* |
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* JFFS2 -- Journalling Flash File System, Version 2. |
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* |
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* Copyright © 2001-2007 Red Hat, Inc. |
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* Copyright © 2004-2010 David Woodhouse <[email protected]> |
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* |
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* Created by David Woodhouse <[email protected]> |
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* |
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* For licensing information, see the file 'LICENCE' in this directory. |
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* |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/kernel.h> |
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#include <linux/jffs2.h> |
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#include <linux/mtd/mtd.h> |
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#include <linux/completion.h> |
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#include <linux/sched/signal.h> |
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#include <linux/freezer.h> |
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#include <linux/kthread.h> |
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#include "nodelist.h" |
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static int jffs2_garbage_collect_thread(void *); |
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void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c) |
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{ |
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assert_spin_locked(&c->erase_completion_lock); |
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if (c->gc_task && jffs2_thread_should_wake(c)) |
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send_sig(SIGHUP, c->gc_task, 1); |
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} |
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/* This must only ever be called when no GC thread is currently running */ |
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int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c) |
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{ |
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struct task_struct *tsk; |
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int ret = 0; |
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BUG_ON(c->gc_task); |
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init_completion(&c->gc_thread_start); |
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init_completion(&c->gc_thread_exit); |
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tsk = kthread_run(jffs2_garbage_collect_thread, c, "jffs2_gcd_mtd%d", c->mtd->index); |
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if (IS_ERR(tsk)) { |
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pr_warn("fork failed for JFFS2 garbage collect thread: %ld\n", |
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-PTR_ERR(tsk)); |
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complete(&c->gc_thread_exit); |
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ret = PTR_ERR(tsk); |
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} else { |
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/* Wait for it... */ |
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jffs2_dbg(1, "Garbage collect thread is pid %d\n", tsk->pid); |
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wait_for_completion(&c->gc_thread_start); |
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ret = tsk->pid; |
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} |
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return ret; |
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} |
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void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c) |
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{ |
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int wait = 0; |
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spin_lock(&c->erase_completion_lock); |
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if (c->gc_task) { |
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jffs2_dbg(1, "Killing GC task %d\n", c->gc_task->pid); |
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send_sig(SIGKILL, c->gc_task, 1); |
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wait = 1; |
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} |
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spin_unlock(&c->erase_completion_lock); |
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if (wait) |
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wait_for_completion(&c->gc_thread_exit); |
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} |
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static int jffs2_garbage_collect_thread(void *_c) |
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{ |
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struct jffs2_sb_info *c = _c; |
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sigset_t hupmask; |
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siginitset(&hupmask, sigmask(SIGHUP)); |
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allow_signal(SIGKILL); |
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allow_signal(SIGSTOP); |
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allow_signal(SIGHUP); |
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c->gc_task = current; |
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complete(&c->gc_thread_start); |
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set_user_nice(current, 10); |
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set_freezable(); |
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for (;;) { |
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sigprocmask(SIG_UNBLOCK, &hupmask, NULL); |
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again: |
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spin_lock(&c->erase_completion_lock); |
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if (!jffs2_thread_should_wake(c)) { |
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set_current_state (TASK_INTERRUPTIBLE); |
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spin_unlock(&c->erase_completion_lock); |
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jffs2_dbg(1, "%s(): sleeping...\n", __func__); |
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schedule(); |
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} else { |
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spin_unlock(&c->erase_completion_lock); |
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} |
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/* Problem - immediately after bootup, the GCD spends a lot |
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* of time in places like jffs2_kill_fragtree(); so much so |
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* that userspace processes (like gdm and X) are starved |
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* despite plenty of cond_resched()s and renicing. Yield() |
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* doesn't help, either (presumably because userspace and GCD |
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* are generally competing for a higher latency resource - |
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* disk). |
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* This forces the GCD to slow the hell down. Pulling an |
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* inode in with read_inode() is much preferable to having |
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* the GC thread get there first. */ |
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schedule_timeout_interruptible(msecs_to_jiffies(50)); |
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if (kthread_should_stop()) { |
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jffs2_dbg(1, "%s(): kthread_stop() called\n", __func__); |
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goto die; |
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} |
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/* Put_super will send a SIGKILL and then wait on the sem. |
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*/ |
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while (signal_pending(current) || freezing(current)) { |
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unsigned long signr; |
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if (try_to_freeze()) |
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goto again; |
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signr = kernel_dequeue_signal(); |
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switch(signr) { |
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case SIGSTOP: |
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jffs2_dbg(1, "%s(): SIGSTOP received\n", |
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__func__); |
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kernel_signal_stop(); |
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break; |
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case SIGKILL: |
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jffs2_dbg(1, "%s(): SIGKILL received\n", |
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__func__); |
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goto die; |
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case SIGHUP: |
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jffs2_dbg(1, "%s(): SIGHUP received\n", |
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__func__); |
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break; |
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default: |
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jffs2_dbg(1, "%s(): signal %ld received\n", |
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__func__, signr); |
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} |
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} |
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/* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */ |
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sigprocmask(SIG_BLOCK, &hupmask, NULL); |
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jffs2_dbg(1, "%s(): pass\n", __func__); |
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if (jffs2_garbage_collect_pass(c) == -ENOSPC) { |
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pr_notice("No space for garbage collection. Aborting GC thread\n"); |
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goto die; |
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} |
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} |
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die: |
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spin_lock(&c->erase_completion_lock); |
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c->gc_task = NULL; |
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spin_unlock(&c->erase_completion_lock); |
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kthread_complete_and_exit(&c->gc_thread_exit, 0); |
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}
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