X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fkthread.c;h=c5f3c6613b6d77dd21d6a0bfcedfbe44d624f802;hb=c7985051dec26dc5ae2562a975a0b37b70621f3f;hp=e377e2244103b28e383e7fc4c4bee120427c1e68;hpb=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2;p=linux-2.6

diff --git a/kernel/kthread.c b/kernel/kthread.c
index e377e22441..c5f3c6613b 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -12,6 +12,7 @@
 #include <linux/unistd.h>
 #include <linux/file.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <asm/semaphore.h>
 
 /*
@@ -41,7 +42,7 @@ struct kthread_stop_info
 
 /* Thread stopping is done by setthing this var: lock serializes
  * multiple kthread_stop calls. */
-static DECLARE_MUTEX(kthread_stop_lock);
+static DEFINE_MUTEX(kthread_stop_lock);
 static struct kthread_stop_info kthread_stop_info;
 
 int kthread_should_stop(void)
@@ -114,7 +115,9 @@ static void keventd_create_kthread(void *_create)
 		create->result = ERR_PTR(pid);
 	} else {
 		wait_for_completion(&create->started);
+		read_lock(&tasklist_lock);
 		create->result = find_task_by_pid(pid);
+		read_unlock(&tasklist_lock);
 	}
 	complete(&create->done);
 }
@@ -164,32 +167,41 @@ void kthread_bind(struct task_struct *k, unsigned int cpu)
 EXPORT_SYMBOL(kthread_bind);
 
 int kthread_stop(struct task_struct *k)
+{
+	return kthread_stop_sem(k, NULL);
+}
+EXPORT_SYMBOL(kthread_stop);
+
+int kthread_stop_sem(struct task_struct *k, struct semaphore *s)
 {
 	int ret;
 
-	down(&kthread_stop_lock);
+	mutex_lock(&kthread_stop_lock);
 
 	/* It could exit after stop_info.k set, but before wake_up_process. */
 	get_task_struct(k);
 
 	/* Must init completion *before* thread sees kthread_stop_info.k */
 	init_completion(&kthread_stop_info.done);
-	wmb();
+	smp_wmb();
 
 	/* Now set kthread_should_stop() to true, and wake it up. */
 	kthread_stop_info.k = k;
-	wake_up_process(k);
+	if (s)
+		up(s);
+	else
+		wake_up_process(k);
 	put_task_struct(k);
 
 	/* Once it dies, reset stop ptr, gather result and we're done. */
 	wait_for_completion(&kthread_stop_info.done);
 	kthread_stop_info.k = NULL;
 	ret = kthread_stop_info.err;
-	up(&kthread_stop_lock);
+	mutex_unlock(&kthread_stop_lock);
 
 	return ret;
 }
-EXPORT_SYMBOL(kthread_stop);
+EXPORT_SYMBOL(kthread_stop_sem);
 
 static __init int helper_init(void)
 {