ntp: improve adjtimex frequency rounding

[safe/jmp/linux-2.6] / kernel / time / clocksource.c

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index c8a9d13..093d4ac 100644 (file)
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -91,7 +91,6 @@ static void clocksource_ratewd(struct clocksource *cs, int64_t delta)
               cs->name, delta);
        cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG);
        clocksource_change_rating(cs, 0);
-       cs->flags &= ~CLOCK_SOURCE_WATCHDOG;
        list_del(&cs->wd_list);
 }
 
@@ -142,8 +141,16 @@ static void clocksource_watchdog(unsigned long data)
        }
 
        if (!list_empty(&watchdog_list)) {
-               __mod_timer(&watchdog_timer,
-                           watchdog_timer.expires + WATCHDOG_INTERVAL);
+               /*
+                * Cycle through CPUs to check if the CPUs stay
+                * synchronized to each other.
+                */
+               int next_cpu = next_cpu_nr(raw_smp_processor_id(), cpu_online_map);
+
+               if (next_cpu >= nr_cpu_ids)
+                       next_cpu = first_cpu(cpu_online_map);
+               watchdog_timer.expires += WATCHDOG_INTERVAL;
+               add_timer_on(&watchdog_timer, next_cpu);
        }
        spin_unlock(&watchdog_lock);
 }
@@ -165,7 +172,8 @@ static void clocksource_check_watchdog(struct clocksource *cs)
                if (!started && watchdog) {
                        watchdog_last = watchdog->read();
                        watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
-                       add_timer(&watchdog_timer);
+                       add_timer_on(&watchdog_timer,
+                                    first_cpu(cpu_online_map));
                }
        } else {
                if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
@@ -186,7 +194,8 @@ static void clocksource_check_watchdog(struct clocksource *cs)
                                watchdog_last = watchdog->read();
                                watchdog_timer.expires =
                                        jiffies + WATCHDOG_INTERVAL;
-                               add_timer(&watchdog_timer);
+                               add_timer_on(&watchdog_timer,
+                                            first_cpu(cpu_online_map));
                        }
                }
        }
@@ -223,6 +232,18 @@ void clocksource_resume(void)
 }
 
 /**
+ * clocksource_touch_watchdog - Update watchdog
+ *
+ * Update the watchdog after exception contexts such as kgdb so as not
+ * to incorrectly trip the watchdog.
+ *
+ */
+void clocksource_touch_watchdog(void)
+{
+       clocksource_resume_watchdog();
+}
+
+/**
  * clocksource_get_next - Returns the selected clocksource
  *
  */
@@ -331,6 +352,21 @@ void clocksource_change_rating(struct clocksource *cs, int rating)
        spin_unlock_irqrestore(&clocksource_lock, flags);
 }
 
+/**
+ * clocksource_unregister - remove a registered clocksource
+ */
+void clocksource_unregister(struct clocksource *cs)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&clocksource_lock, flags);
+       list_del(&cs->list);
+       if (clocksource_override == cs)
+               clocksource_override = NULL;
+       next_clocksource = select_clocksource();
+       spin_unlock_irqrestore(&clocksource_lock, flags);
+}
+
 #ifdef CONFIG_SYSFS
 /**
  * sysfs_show_current_clocksources - sysfs interface for current clocksource
@@ -340,17 +376,16 @@ void clocksource_change_rating(struct clocksource *cs, int rating)
  * Provides sysfs interface for listing current clocksource.
  */
 static ssize_t
-sysfs_show_current_clocksources(struct sys_device *dev, char *buf)
+sysfs_show_current_clocksources(struct sys_device *dev,
+                               struct sysdev_attribute *attr, char *buf)
 {
-       char *curr = buf;
+       ssize_t count = 0;
 
        spin_lock_irq(&clocksource_lock);
-       curr += sprintf(curr, "%s ", curr_clocksource->name);
+       count = snprintf(buf, PAGE_SIZE, "%s\n", curr_clocksource->name);
        spin_unlock_irq(&clocksource_lock);
 
-       curr += sprintf(curr, "\n");
-
-       return curr - buf;
+       return count;
 }
 
 /**
@@ -363,6 +398,7 @@ sysfs_show_current_clocksources(struct sys_device *dev, char *buf)
  * clocksource selction.
  */
 static ssize_t sysfs_override_clocksource(struct sys_device *dev,
+                                         struct sysdev_attribute *attr,
                                          const char *buf, size_t count)
 {
        struct clocksource *ovr = NULL;
@@ -415,33 +451,38 @@ static ssize_t sysfs_override_clocksource(struct sys_device *dev,
  * Provides sysfs interface for listing registered clocksources
  */
 static ssize_t
-sysfs_show_available_clocksources(struct sys_device *dev, char *buf)
+sysfs_show_available_clocksources(struct sys_device *dev,
+                                 struct sysdev_attribute *attr,
+                                 char *buf)
 {
        struct clocksource *src;
-       char *curr = buf;
+       ssize_t count = 0;
 
        spin_lock_irq(&clocksource_lock);
        list_for_each_entry(src, &clocksource_list, list) {
-               curr += sprintf(curr, "%s ", src->name);
+               count += snprintf(buf + count,
+                                 max((ssize_t)PAGE_SIZE - count, (ssize_t)0),
+                                 "%s ", src->name);
        }
        spin_unlock_irq(&clocksource_lock);
 
-       curr += sprintf(curr, "\n");
+       count += snprintf(buf + count,
+                         max((ssize_t)PAGE_SIZE - count, (ssize_t)0), "\n");
 
-       return curr - buf;
+       return count;
 }
 
 /*
  * Sysfs setup bits:
  */
-static SYSDEV_ATTR(current_clocksource, 0600, sysfs_show_current_clocksources,
+static SYSDEV_ATTR(current_clocksource, 0644, sysfs_show_current_clocksources,
                   sysfs_override_clocksource);
 
-static SYSDEV_ATTR(available_clocksource, 0600,
+static SYSDEV_ATTR(available_clocksource, 0444,
                   sysfs_show_available_clocksources, NULL);
 
 static struct sysdev_class clocksource_sysclass = {
-       set_kset_name("clocksource"),
+       .name = "clocksource",
 };
 
 static struct sys_device device_clocksource = {