[Devel] Re: [PATCH] i386 voyager: Convert the monitor thread to use the kthread API

[Christoph Hellwig]

On Thu, Apr 19, 2007 at 12:55:27AM -0600, Eric W. Biederman wrote:
> From: Eric W. Biederman <ebiederm at xmission.com> - unquoted
> 
> This patch just trivially replaces kernel_thread and daemonize
> with a single call to kthread_run.

Here's a better patch that does the full kthread conversion +
switch to wake_up_process.  Only compile tested of course due to
lack of voyager hardware.


Signed-off-by: Christoph Hellwig <hch at lst.de>

Index: linux-2.6/arch/i386/mach-voyager/voyager_cat.c
===================================================================
--- linux-2.6.orig/arch/i386/mach-voyager/voyager_cat.c	2007-04-22 15:19:28.000000000 +0200
+++ linux-2.6/arch/i386/mach-voyager/voyager_cat.c	2007-04-22 15:27:03.000000000 +0200
@@ -1111,7 +1111,7 @@ voyager_cat_do_common_interrupt(void)
 				printk(KERN_ERR "Voyager front panel switch turned off\n");
 				voyager_status.switch_off = 1;
 				voyager_status.request_from_kernel = 1;
-				up(&kvoyagerd_sem);
+				wake_up_process(voyager_thread);
 			}
 			/* Tell the hardware we're taking care of the
 			 * shutdown, otherwise it will power the box off
@@ -1157,7 +1157,7 @@ voyager_cat_do_common_interrupt(void)
 			outb(VOYAGER_CAT_END, CAT_CMD);
 			voyager_status.power_fail = 1;
 			voyager_status.request_from_kernel = 1;
-			up(&kvoyagerd_sem);
+			wake_up_process(voyager_thread);
 		}
 		
 		
Index: linux-2.6/arch/i386/mach-voyager/voyager_thread.c
===================================================================
--- linux-2.6.orig/arch/i386/mach-voyager/voyager_thread.c	2007-04-22 15:15:24.000000000 +0200
+++ linux-2.6/arch/i386/mach-voyager/voyager_thread.c	2007-04-22 15:25:51.000000000 +0200
@@ -24,33 +24,16 @@
 #include <linux/kmod.h>
 #include <linux/completion.h>
 #include <linux/sched.h>
+#include <linux/kthread.h>
 #include <asm/desc.h>
 #include <asm/voyager.h>
 #include <asm/vic.h>
 #include <asm/mtrr.h>
 #include <asm/msr.h>
 
-#define THREAD_NAME "kvoyagerd"
 
-/* external variables */
-int kvoyagerd_running = 0;
-DECLARE_MUTEX_LOCKED(kvoyagerd_sem);
-
-static int thread(void *);
-
-static __u8 set_timeout = 0;
-
-/* Start the machine monitor thread.  Return 1 if OK, 0 if fail */
-static int __init
-voyager_thread_start(void)
-{
-	if(kernel_thread(thread, NULL, CLONE_KERNEL) < 0) {
-		/* This is serious, but not fatal */
-		printk(KERN_ERR "Voyager: Failed to create system monitor thread!!!\n");
-		return 1;
-	}
-	return 0;
-}
+struct task_struct *voyager_thread;
+static __u8 set_timeout;
 
 static int
 execute(const char *string)
@@ -110,31 +93,15 @@ check_continuing_condition(void)
 	}
 }
 
-static void
-wakeup(unsigned long unused)
-{
-	up(&kvoyagerd_sem);
-}
-
 static int
 thread(void *unused)
 {
-	struct timer_list wakeup_timer;
-
-	kvoyagerd_running = 1;
-
-	daemonize(THREAD_NAME);
-
-	set_timeout = 0;
-
-	init_timer(&wakeup_timer);
-
-	sigfillset(&current->blocked);
-
 	printk(KERN_NOTICE "Voyager starting monitor thread\n");
 
-	for(;;) {
-		down_interruptible(&kvoyagerd_sem);
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(set_timeout ? HZ : MAX_SCHEDULE_TIMEOUT);
+
 		VDEBUG(("Voyager Daemon awoken\n"));
 		if(voyager_status.request_from_kernel == 0) {
 			/* probably awoken from timeout */
@@ -143,20 +110,26 @@ thread(void *unused)
 			check_from_kernel();
 			voyager_status.request_from_kernel = 0;
 		}
-		if(set_timeout) {
-			del_timer(&wakeup_timer);
-			wakeup_timer.expires = HZ + jiffies;
-			wakeup_timer.function = wakeup;
-			add_timer(&wakeup_timer);
-		}
 	}
 }
 
+static int __init
+voyager_thread_start(void)
+{
+	voyager_thread = kthread_run(thread, NULL, "kvoyagerd");
+	if (IS_ERR(voyager_thread)) {
+		printk(KERN_ERR "Voyager: Failed to create system monitor thread.\n");
+		return PTR_ERR(voyager_thread);
+	}
+	return 0;
+}
+
+
 static void __exit
 voyager_thread_stop(void)
 {
-	/* FIXME: do nothing at the moment */
+	kthread_stop(voyager_thread);
 }
 
 module_init(voyager_thread_start);
-//module_exit(voyager_thread_stop);
+module_exit(voyager_thread_stop);
Index: linux-2.6/include/asm-i386/voyager.h
===================================================================
--- linux-2.6.orig/include/asm-i386/voyager.h	2007-04-22 15:18:39.000000000 +0200
+++ linux-2.6/include/asm-i386/voyager.h	2007-04-22 15:24:13.000000000 +0200
@@ -487,15 +487,11 @@ extern struct voyager_qic_cpi *voyager_q
 extern struct voyager_SUS *voyager_SUS;
 
 /* variables exported always */
+extern struct task_struct *voyager_thread;
 extern int voyager_level;
-extern int kvoyagerd_running;
-extern struct semaphore kvoyagerd_sem;
 extern struct voyager_status voyager_status;
 
-
-
 /* functions exported by the voyager and voyager_smp modules */
-
 extern int voyager_cat_readb(__u8 module, __u8 asic, int reg);
 extern void voyager_cat_init(void);
 extern void voyager_detect(struct voyager_bios_info *);
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