From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753411Ab1A1Axl (ORCPT ); Thu, 27 Jan 2011 19:53:41 -0500 Received: from x35.xmailserver.org ([64.71.152.41]:35940 "EHLO x35.xmailserver.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752576Ab1A1Axk (ORCPT ); Thu, 27 Jan 2011 19:53:40 -0500 X-AuthUser: davidel@xmailserver.org Date: Thu, 27 Jan 2011 16:53:39 -0800 (PST) From: Davide Libenzi X-X-Sender: davide@localhost6.localdomain6 To: Alexander Gordeev cc: uClibc , Linux Kernel Mailing List Subject: Re: timerfd incompatibility on mips In-Reply-To: <20110128032443.6f8b877e@apollo.gnet> Message-ID: References: <20110128032443.6f8b877e@apollo.gnet> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) X-GPG-FINGRPRINT: CFAE 5BEE FD36 F65E E640 56FE 0974 BF23 270F 474E X-GPG-PUBLIC_KEY: http://www.xmailserver.org/davidel.asc MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 28 Jan 2011, Alexander Gordeev wrote: > Hi! > > I've just found a problem with TFD_NONBLOCK flag that can be passed to > timerfd_create. > > /libc/sysdeps/linux/common/sys/timerfd.h which is installed > to /usr/include/sys/timerfd.h defines TFD_NONBLOCK as 04000 ie 0x800. > BTW glibc/eglibc headers do the same thing. > > /include/linux/timerfd.h declares it as O_NONBLOCK which is > defined in fcntl.h. Usually O_NONBLOCK is 0x800 too but some > architectures including MIPS it redefine it: > > arch/mips/include/asm/fcntl.h:#define O_NONBLOCK 0x0080 > arch/alpha/include/asm/fcntl.h:#define O_NONBLOCK 00004 > arch/sparc/include/asm/fcntl.h:#define O_NONBLOCK 0x4000 > arch/parisc/include/asm/fcntl.h:#define O_NONBLOCK 000200004 > > My tests show that kernel thinks that TFD_NONBLOCK is 0x80 on MIPS. I > get what I want when I pass 0x80 and EINVAL when I pass 0x800. I don't > know why there are such uncertain things in Linux. Probably the problem > should be fixed in the kernel. > > Right now one cannot use timerfd_create(..., TFD_NONBLOCK) on MIPS but > can use timerfd_create(..., O_NONBLOCK) instead. Ther kernel definition (include/linux/timerfd.h) maps it directly to O_NONBLOCK, but I am noticing that glibc bolt in the value. I don't think this is a kernel fix. - Davide