Drop. Signed-Off-By: Daniel Walker --- 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); -- - 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/