[patch] "big IRQ lock" removal, 2.5.27-A5

Ingo Molnar
2002-07-21T20:40:13Z

reviewed and fixed the apm.c hacks, it's now using the proper spinlocks
and not cli()/sti(). Latest full patch is at:

http://redhat.com/~mingo/remove-irqlock-patches/remove-irqlock-2.5.27-A5

(the apm.c changes are attached as well.)

Ingo

--- linux/arch/i386/kernel/apm.c.orig Sun Jul 21 20:37:10 2002
+++ linux/arch/i386/kernel/apm.c Sun Jul 21 22:36:42 2002
@@ -222,6 +222,8 @@

#include <linux/sysrq.h>

+extern rwlock_t xtime_lock;
+extern spinlock_t i8253_lock;
extern unsigned long get_cmos_time(void);
extern void machine_real_restart(unsigned char *, int);

@@ -1141,40 +1143,25 @@

static void set_time(void)
{
- unsigned long flags;
-
- if (got_clock_diff) { /* Must know time zone in order to set clock */
- save_flags(flags);
- cli();
+ if (got_clock_diff) /* Must know time zone in order to set clock */
CURRENT_TIME = get_cmos_time() + clock_cmos_diff;
- restore_flags(flags);
- }
}

static void get_time_diff(void)
{
#ifndef CONFIG_APM_RTC_IS_GMT
- unsigned long flags;
-
/*
* Estimate time zone so that set_time can update the clock
*/
- save_flags(flags);
clock_cmos_diff = -get_cmos_time();
- cli();
clock_cmos_diff += CURRENT_TIME;
got_clock_diff = 1;
- restore_flags(flags);
#endif
}

-static void reinit_timer(void)
+static inline void reinit_timer(void)
{
#ifdef INIT_TIMER_AFTER_SUSPEND
- unsigned long flags;
-
- save_flags(flags);
- cli();
/* set the clock to 100 Hz */
outb_p(0x34,0x43); /* binary, mode 2, LSB/MSB, ch 0 */
udelay(10);
@@ -1182,7 +1169,6 @@
udelay(10);
outb(LATCH >> 8 , 0x40); /* MSB */
udelay(10);
- restore_flags(flags);
#endif
}

@@ -1203,13 +1189,21 @@
}
printk(KERN_CRIT "apm: suspend was vetoed, but suspending anyway.\n");
}
+ /* serialize with the timer interrupt */
+ write_lock_irq(&xtime_lock);
+
+ /* protect against access to timer chip registers */
+ spin_lock(&i8253_lock);
+
get_time_diff();
- cli();
err = set_system_power_state(APM_STATE_SUSPEND);
reinit_timer();
set_time();
ignore_normal_resume = 1;
- sti();
+
+ spin_unlock(&i8253_lock);
+ write_unlock_irq(&xtime_lock);
+
if (err == APM_NO_ERROR)
err = APM_SUCCESS;
if (err != APM_SUCCESS)
@@ -1232,8 +1226,12 @@
{
int err;

+ /* serialize with the timer interrupt */
+ write_lock_irq(&xtime_lock);
/* If needed, notify drivers here */
get_time_diff();
+ write_unlock_irq(&xtime_lock);
+
err = set_system_power_state(APM_STATE_STANDBY);
if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
apm_error("standby", err);
@@ -1321,7 +1319,9 @@
ignore_bounce = 1;
if ((event != APM_NORMAL_RESUME)
|| (ignore_normal_resume == 0)) {
+ write_lock_irq(&xtime_lock);
set_time();
+ write_unlock_irq(&xtime_lock);
pm_send_all(PM_RESUME, (void *)0);
queue_event(event, NULL);
}
@@ -1336,7 +1336,9 @@
break;

case APM_UPDATE_TIME:
+ write_lock_irq(&xtime_lock);
set_time();
+ write_unlock_irq(&xtime_lock);
break;