Re: Wireless IBSS on Linux-2.6.34 broken by commit3bbb9ec946428b96657126768f65487a48dd090c

From: Jeff Chua
Date: Sun May 23 2010 - 19:16:33 EST



Mon, May 24, 2010 at 5:25 AM, Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> wrote:
can you try, instead do the following, in the apply_slack() function:

just before the return expires_limit; do

if (expires_limit< expires)
# # #expires_limit = expires;

This doesn't work.


if that does not fix it, a second thought:
add, after the first if (timer->slack< 0)

if (timer->slack< 0&& expires< jiffies)
# # # #expires_limit = expires;

This works.

hmm ok so the wireless stack sets a timer way back in the past
ok that's technically legal.

how about

expires_limit = expires;

if (timer->slack > -1)
expires_limit = expires + timer->slack;
else if (time_after(expires, jiffies))
expires_limit = expires + (expires - jiffies)/256;

can you test such a thing and send a patch?
(it has my Acked-By: either way)


Arjan,

Tested and working. Here's the patch. Thanks for the fix!

Jeff



--- a/kernel/timer.c.org 2010-05-24 07:09:04.000000000 +0800
+++ a/kernel/timer.c 2010-05-24 07:05:22.000000000 +0800
@@ -750,9 +750,11 @@
unsigned long expires_limit, mask;
int bit;

- expires_limit = expires + timer->slack;
+ expires_limit = expires;

- if (timer->slack < 0) /* auto slack: use 0.4% */
+ if (timer->slack > -1)
+ expires_limit = expires + timer->slack;
+ else if (time_after(expires, jiffies)) /* auto slack: use 0.4% */
expires_limit = expires + (expires - jiffies)/256;

mask = expires ^ expires_limit;


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