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Subject[PATCH 05/23] clocksource: drop simplify-the-registration-of-clocksources.patch
Drop.

Signed-Off-By: Daniel Walker <dwalker@mvista.com>

---
include/linux/clocksource.h | 3 -
kernel/time/clocksource.c | 118 ++++++++++++++++++++++----------------------
2 files changed, 61 insertions(+), 60 deletions(-)

Index: linux-2.6.19/include/linux/clocksource.h
===================================================================
--- linux-2.6.19.orig/include/linux/clocksource.h
+++ linux-2.6.19/include/linux/clocksource.h
@@ -198,7 +198,4 @@ static inline void update_vsyscall(struc
}
#endif

-#define clocksource_reselect() clocksource_change_rating(&clocksource_tsc, clocksource_tsc.rating)
-extern void clocksource_change_rating(struct clocksource *cs, int rating);
-
#endif /* _LINUX_CLOCKSOURCE_H */
Index: linux-2.6.19/kernel/time/clocksource.c
===================================================================
--- linux-2.6.19.orig/kernel/time/clocksource.c
+++ linux-2.6.19/kernel/time/clocksource.c
@@ -47,7 +47,6 @@ extern struct clocksource clocksource_ji
*/
static struct clocksource *curr_clocksource = &clocksource_jiffies;
static struct clocksource *next_clocksource;
-static struct clocksource *clocksource_override;
static LIST_HEAD(clocksource_list);
static DEFINE_SPINLOCK(clocksource_lock);
static char override_name[32];
@@ -84,46 +83,60 @@ struct clocksource *clocksource_get_next
}

/**
- * select_clocksource - Selects the best registered clocksource.
+ * select_clocksource - Finds the best registered clocksource.
*
* Private function. Must hold clocksource_lock when called.
*
- * Select the clocksource with the best rating, or the clocksource,
- * which is selected by userspace override.
+ * Looks through the list of registered clocksources, returning
+ * the one with the highest rating value. If there is a clocksource
+ * name that matches the override string, it returns that clocksource.
*/
static struct clocksource *select_clocksource(void)
{
- if (list_empty(&clocksource_list))
- return NULL;
+ struct clocksource *best = NULL;
+ struct list_head *tmp;
+
+ list_for_each(tmp, &clocksource_list) {
+ struct clocksource *src;

- if (clocksource_override)
- return clocksource_override;
+ src = list_entry(tmp, struct clocksource, list);
+ if (!best)
+ best = src;
+
+ /* check for override: */
+ if (strlen(src->name) == strlen(override_name) &&
+ !strcmp(src->name, override_name)) {
+ best = src;
+ break;
+ }
+ /* pick the highest rating: */
+ if (src->rating > best->rating)
+ best = src;
+ }

- return list_entry(clocksource_list.next, struct clocksource, list);
+ return best;
}

-/*
- * Enqueue the clocksource sorted by rating
+/**
+ * is_registered_source - Checks if clocksource is registered
+ * @c: pointer to a clocksource
+ *
+ * Private helper function. Must hold clocksource_lock when called.
+ *
+ * Returns one if the clocksource is already registered, zero otherwise.
*/
-static int clocksource_enqueue(struct clocksource *c)
+static int is_registered_source(struct clocksource *c)
{
- struct list_head *tmp, *entry = &clocksource_list;
+ int len = strlen(c->name);
+ struct list_head *tmp;

list_for_each(tmp, &clocksource_list) {
- struct clocksource *cs;
+ struct clocksource *src;

- cs = list_entry(tmp, struct clocksource, list);
- if (cs == c)
- return -EBUSY;
- /* Keep track of the place, where to insert */
- if (cs->rating >= c->rating)
- entry = tmp;
+ src = list_entry(tmp, struct clocksource, list);
+ if (strlen(src->name) == len && !strcmp(src->name, c->name))
+ return 1;
}
- list_add(&c->list, entry);
-
- if (strlen(c->name) == strlen(override_name) &&
- !strcmp(c->name, override_name))
- clocksource_override = c;

return 0;
}
@@ -136,32 +149,42 @@ static int clocksource_enqueue(struct cl
*/
int clocksource_register(struct clocksource *c)
{
- unsigned long flags;
int ret = 0;
+ unsigned long flags;

spin_lock_irqsave(&clocksource_lock, flags);
- ret = clocksource_enqueue(c);
- if (!ret)
+ /* check if clocksource is already registered */
+ if (is_registered_source(c)) {
+ printk("register_clocksource: Cannot register %s. "
+ "Already registered!", c->name);
+ ret = -EBUSY;
+ } else {
+ /* register it */
+ list_add(&c->list, &clocksource_list);
+ /* scan the registered clocksources, and pick the best one */
next_clocksource = select_clocksource();
+ }
spin_unlock_irqrestore(&clocksource_lock, flags);
return ret;
}
EXPORT_SYMBOL(clocksource_register);

/**
- * clocksource_change_rating - Change the rating of a registered clocksource
+ * clocksource_reselect - Rescan list for next clocksource
*
+ * A quick helper function to be used if a clocksource changes its
+ * rating. Forces the clocksource list to be re-scanned for the best
+ * clocksource.
*/
-void clocksource_change_rating(struct clocksource *cs, int rating)
+void clocksource_reselect(void)
{
unsigned long flags;

spin_lock_irqsave(&clocksource_lock, flags);
- list_del(&cs->list);
- clocksource_enqueue(cs);
next_clocksource = select_clocksource();
spin_unlock_irqrestore(&clocksource_lock, flags);
}
+EXPORT_SYMBOL(clocksource_reselect);

#ifdef CONFIG_SYSFS
/**
@@ -197,11 +220,7 @@ sysfs_show_current_clocksources(struct s
static ssize_t sysfs_override_clocksource(struct sys_device *dev,
const char *buf, size_t count)
{
- struct clocksource *ovr = NULL;
- struct list_head *tmp;
size_t ret = count;
- int len;
-
/* strings from sysfs write are not 0 terminated! */
if (count >= sizeof(override_name))
return -EINVAL;
@@ -209,32 +228,17 @@ static ssize_t sysfs_override_clocksourc
/* strip of \n: */
if (buf[count-1] == '\n')
count--;
+ if (count < 1)
+ return -EINVAL;

spin_lock_irq(&clocksource_lock);

- if (count > 0)
- memcpy(override_name, buf, count);
+ /* copy the name given: */
+ memcpy(override_name, buf, count);
override_name[count] = 0;

- len = strlen(override_name);
- if (len) {
- ovr = clocksource_override;
- /* try to select it: */
- list_for_each(tmp, &clocksource_list) {
- struct clocksource *cs;
-
- cs = list_entry(tmp, struct clocksource, list);
- if (strlen(cs->name) == len &&
- !strcmp(cs->name, override_name))
- ovr = cs;
- }
- }
-
- /* Reselect, when the override name has changed */
- if (ovr != clocksource_override) {
- clocksource_override = ovr;
- next_clocksource = select_clocksource();
- }
+ /* try to select it: */
+ next_clocksource = select_clocksource();

spin_unlock_irq(&clocksource_lock);

--
-
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