[Xenomai-core] [patch, minor] xnpipe_recv and # CPE_ANT_R6.2 (Slotted release R6) - ModemSoftware bant-z # Sun Aug 20 08:24:02 MEST 2006 element * CHECKEDOUT # linxiangcheng # Sat Aug 19 09:47:12 MEST 2006 # fix the bug: CPE_P00016456 element /cm4/fsn/app/pstack/sl

[Xenomai-core] [patch, minor] xnpipe_recv and # CPE_ANT_R6.2 (Slotted release R6) - ModemSoftware bant-z # Sun Aug 20 08:24:02 MEST 2006 element * CHECKEDOUT # linxiangcheng # Sat Aug 19 09:47:12 MEST 2006 # fix the bug: CPE_P00016456 element /cm4/fsn/app/pstack/sl

[Dmitry Adamushko]

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Hello,

[ pipe.c.patch ]  update the "timeout" variable so that the remaining
timeout is used in case of consequent xnsynch_sleep_on() calls.

As I understand that may indeed happen in case when another thread "steals"
data while this one waits to be scheduled in.

[ timer.c.patch] xnticks_t is unsigned while (as I understand)
"xntlholder_date(&timer->plink) - nkpod->jiffies" can be negative.
In this case, some positive big number is returned and any code that relies
on xnthread_timeout() or xntimer_get_timeout() and runs over periodic mode
won't work properly (e.g. xnsynch_sleep_on() and xnpipe_recv() now). Not
sure 1 should be returned in this case (so far I just did it the same way as
xntimer_get_timeout_aperiodic()), I guess 0 would be better in both cases.

At least in theory, 1 may cause an (even) infinite loop in xnpipe_recv() as
I don't like a check for "timeout > 1" to be placed there. It's something
that should be decided at the timer layer - I mean, whether it's too late to
sleep or not.

hope, I haven't overlooked anything this time :o)


-- 
Best regards,
Dmitry Adamushko

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--- pipe-SVN.c	2006-08-20 15:04:25.000000000 +0200
+++ pipe.c	2006-08-20 21:29:55.000000000 +0200
@@ -450,6 +450,9 @@ ssize_t xnpipe_recv(int minor, struct xn
 			ret = -EIDRM;
 			goto unlock_and_exit;
 		}
+
+		/* remaining timeout */		
+		timeout = xnthread_timeout(thread);
 	}
 
 	*pmh = link2mh(holder);

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--- timer-SVN.c	2006-08-20 15:50:18.000000000 +0200
+++ timer.c	2006-08-20 15:54:30.000000000 +0200
@@ -313,7 +313,12 @@ static xnticks_t xntimer_get_date_period
 
 static xnticks_t xntimer_get_timeout_periodic(xntimer_t *timer)
 {
-	return xntlholder_date(&timer->plink) - nkpod->jiffies;
+	xnticks_t now = nkpod->jiffies;
+	
+	if (xntlholder_date(&timer->plink) < now)
+		return 1;	/* Will elapse shortly. */
+	
+	return xntlholder_date(&timer->plink) - now;
 }
 
 static xnticks_t xntimer_get_raw_expiry_periodic(xntimer_t *timer)

Re: [Xenomai-core] [patch, minor] xnpipe_recv and # CPE_ANT_R6.2 (Slotted release R6) - ModemSoftware bant-z # Sun Aug 20 08:24:02 MEST 2006 element * CHECKEDOUT # linxiangcheng # Sat Aug 19 09:47:12 MEST 2006 # fix the bug: CPE_P00016456 element /cm4/fsn/app/pstack/sl

[Philippe Gerum]

On Mon, 2006-08-21 at 10:34 +0200, Dmitry Adamushko wrote:

> [ pipe.c.patch ]  update the "timeout" variable so that the remaining
> timeout is used in case of consequent xnsynch_sleep_on() calls.

Applied, thanks.

-- 
Philippe.