From: Nish Aravamudan <nish.aravamudan@gmail.com>
To: Davide Libenzi <davidel@xmailserver.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>
Subject: Re: [patch] Make epoll_wait() handle negative timeouts as MAX_SCHEDULE_TIMEOUT ...
Date: Fri, 23 Sep 2005 10:42:23 -0700 [thread overview]
Message-ID: <29495f1d0509231042139e9b94@mail.gmail.com> (raw)
In-Reply-To: <Pine.LNX.4.63.0509231031570.10222@localhost.localdomain>
On 9/23/05, Davide Libenzi <davidel@xmailserver.org> wrote:
>
> As reported by Vadim Lobanov, epoll_wait() did not handle correctly
> timeouts <0 (only the -1 case was MAX_SCHEDULE_TIMEOUT'd).
>
>
> Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Arrgggh, this is as wrong as sys_poll() was before! :)
--- a/fs/eventpoll.c 2005-09-23 10:06:45.000000000 -0700
+++ b/fs/eventpoll.c 2005-09-23 10:09:35.000000000 -0700
@@ -1507,7 +1507,7 @@
* and the overflow condition. The passed timeout is in milliseconds,
* that why (t * HZ) / 1000.
*/
- jtimeout = timeout == -1 || timeout > (MAX_SCHEDULE_TIMEOUT - 1000) / HZ ?
+ jtimeout = timeout < 0 || timeout > (MAX_SCHEDULE_TIMEOUT - 1000) / HZ ?
@timeout is in miliseconds, per the comment, yes? If so, then
timeout [msecs] > MAX_SCHEDULE_TIMEOUT [jiffies] - 1000 [jiffies] / HZ
[jiffies / sec]
compares milliseconds to seconds! (Don't worry, sys_poll() had the
same error for a long time). There is a patch in 2.6.14-rc2-mm1 for
sys_poll() to fix the handling of long timeouts, please take a look
and maybe apply the same ideas to epoll(). Alexey Dobriyan has filed a
regression against the patch, but I'm unable to reproduce it (and it
could be an app depending on the old broken behavior).
Thanks,
Nish
next prev parent reply other threads:[~2005-09-23 17:42 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-23 17:37 [patch] Make epoll_wait() handle negative timeouts as MAX_SCHEDULE_TIMEOUT Davide Libenzi
2005-09-23 17:42 ` Nish Aravamudan [this message]
2005-09-23 18:04 ` Davide Libenzi
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