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alarm: skip timed out alarms when inserting in procalarm() (thanks erik)

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from erik quanstros 9fans post:

i think the list insertion code needs a single-read
test that f->alarm != 0. to prevent the 0 from
acting like a fencepost.  e.g. trying to insert -10 into
list -40 -30 0 -20.

	if(alarms.head) {
		l = &alarms.head;
		for(f = *l; f; f = f->palarm) {
>>			fw = f->alarm;
>>			if(fw != 0 && (long)(fw - when) >= 0) {
				up->palarm = f;
				*l = up;
				goto done;
			}
			l = &f->palarm;
		}
		*l = up;
	}
This commit is contained in:
cinap_lenrek 2014-01-03 01:40:17 +01:00
parent d1be5e163c
commit 8ebe3f680e
1 changed files with 2 additions and 1 deletions
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3
sys/src/9/port/alarm.c
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@ -88,7 +88,8 @@ procalarm(ulong time)
if(alarms.head) { if(alarms.head) {
l = &alarms.head; l = &alarms.head;
for(f = *l; f; f = f->palarm) { for(f = *l; f; f = f->palarm) {
if((long)(f->alarm - when) >= 0) { time = f->alarm;
if(time != 0 && (long)(time - when) >= 0) {
up->palarm = f; up->palarm = f;
*l = up; *l = up;
goto done; goto done;