Hi Linus,
the appended patch adds a small and lightweigt 'kthread' layer that
simplifies creating kernel daemons for drivers/filesystems/etc.
Currently there is lots of duplicated code doing the setup of this
threads which is hard to maintain and error-prone.
For an description of the API please take a look at:
http://lwn.net/2002/0214/a/kthread.php3
Please apply,
Christoph
-- Of course it doesn't work. We've performed a software upgrade.diff -uNr -Xdontdiff ../master/linux-2.5.4-pre5/include/linux/kthread.h linux/include/linux/kthread.h --- ../master/linux-2.5.4-pre5/include/linux/kthread.h Thu Jan 1 01:00:00 1970 +++ linux/include/linux/kthread.h Sat Feb 9 17:43:12 2002 @@ -0,0 +1,22 @@ +#ifndef _LINUX_KTHREAD_H +#define _LINUX_KTHREAD_H + +struct task_struct; + +struct kthread { + const char *name; + struct task_struct *task; + struct completion done; +#define KTH_RUNNING 1 +#define KTH_SHUTDOWN 2 + long state; + int (*init)(struct kthread *, void *); + void (*cleanup)(struct kthread *, void *); + int (*main)(struct kthread *, void *); +}; + +extern int kthread_start(struct kthread *, void *); +extern void kthread_stop(struct kthread *); +extern int kthread_running(struct kthread *); + +#endif /* _LINUX_KTHREAD_H */ diff -uNr -Xdontdiff ../master/linux-2.5.4-pre5/kernel/Makefile linux/kernel/Makefile --- ../master/linux-2.5.4-pre5/kernel/Makefile Fri Feb 1 16:27:04 2002 +++ linux/kernel/Makefile Sat Feb 9 17:42:58 2002 @@ -10,12 +10,12 @@ O_TARGET := kernel.o export-objs = signal.o sys.o kmod.o context.o ksyms.o pm.o exec_domain.o \ - printk.o + printk.o kthread.o obj-y = sched.o dma.o fork.o exec_domain.o panic.o printk.o \ module.o exit.o itimer.o info.o time.o softirq.o resource.o \ sysctl.o acct.o capability.o ptrace.o timer.o user.o \ - signal.o sys.o kmod.o context.o + signal.o sys.o kmod.o context.o kthread.o obj-$(CONFIG_UID16) += uid16.o obj-$(CONFIG_MODULES) += ksyms.o diff -uNr -Xdontdiff ../master/linux-2.5.4-pre5/kernel/kthread.c linux/kernel/kthread.c --- ../master/linux-2.5.4-pre5/kernel/kthread.c Thu Jan 1 01:00:00 1970 +++ linux/kernel/kthread.c Sat Feb 9 17:43:47 2002 @@ -0,0 +1,148 @@ +/* + * Copyright (c) 2002 Christoph Hellwig. + * All rights resered. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <linux/completion.h> +#include <linux/kernel.h> +#include <linux/kthread.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/sched.h> +#include <linux/signal.h> +#include <linux/smp_lock.h> +#include <linux/spinlock.h> +#include <asm/bitops.h> + +#define KTHREAD_FLAGS \ + (CLONE_FS|CLONE_FILES|CLONE_SIGHAND) + +struct kthread_args { + struct kthread *kth; + void *data; +}; + + +static int kthread_stopped(struct kthread *kth) +{ + struct task_struct *task = kth->task; + unsigned long signr; + siginfo_t info; + + spin_lock_irq(&task->sigmask_lock); + signr = dequeue_signal(&task->blocked, &info); + spin_unlock_irq(&task->sigmask_lock); + + if (signr == SIGKILL && test_bit(KTH_SHUTDOWN, &kth->state)) + return 1; + return 0; +} + +static int kthread_main(void *p) +{ + struct kthread_args *args = p; + struct kthread *kth = args->kth; + void *data = args->data; + + lock_kernel(); + daemonize(); + reparent_to_init(); + strcpy(current->comm, kth->name); + unlock_kernel(); + + kth->task = current; + + spin_lock_irq(¤t->sigmask_lock); + siginitsetinv(¤t->blocked, + sigmask(SIGHUP) | sigmask(SIGKILL) | + sigmask(SIGSTOP) | sigmask(SIGCONT)); + spin_unlock_irq(¤t->sigmask_lock); + + if (kth->init) + kth->init(kth, data); + complete(&kth->done); + + do { + if (kth->main(kth, data) < 0) + break; + } while (!kthread_stopped(kth)); + + if (kth->cleanup) + kth->cleanup(kth, data); + clear_bit(KTH_RUNNING, &kth->state); + complete(&kth->done); + return 0; +} + +/** + * kthread_start - start a new kernel thread + * @kth: kernel thread description + * @data: opaque data for use with the methods + * + * For off a new kernel thread as described by @kth. + */ +int kthread_start(struct kthread *kth, void *data) +{ + struct kthread_args args; + pid_t pid; + + if (!kth->name || !kth->main) + return -EINVAL; + + args.kth = kth; + args.data = data; + + init_completion(&kth->done); + if ((pid = kernel_thread(kthread_main, &args, KTHREAD_FLAGS)) < 0) + return pid; + set_bit(KTH_RUNNING, &kth->state); + wait_for_completion(&kth->done); + return 0; +} + +/** + * kthread_stop - stop a kernel thread + * @kth: kernel thread description + * + * Stop the kernel thread described by @kth. + */ +void kthread_stop(struct kthread *kth) +{ + if (kth->task) { + init_completion(&kth->done); + set_bit(KTH_SHUTDOWN, &kth->state); + send_sig(SIGKILL, kth->task, 1); + wait_for_completion(&kth->done); + kth->task = NULL; + clear_bit(KTH_SHUTDOWN, &kth->state); + } +} + +/** + * kthread_running - check whether a kernel thread is running + * @kth: kernel thread description + * + * Checks whether the kernel thread described by @kth is running. + */ +int kthread_running(struct kthread *kth) +{ + return test_bit(KTH_RUNNING, &kth->state); +} + +EXPORT_SYMBOL(kthread_start); +EXPORT_SYMBOL(kthread_stop); +EXPORT_SYMBOL(kthread_running); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Thu Mar 07 2002 - 21:00:56 EST