From: Alexander Gordeev <lasaine@lvk.cs.msu.su>
To: Davide Libenzi <davidel@xmailserver.org>
Cc: uClibc <uclibc@uclibc.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: timerfd incompatibility on mips
Date: Fri, 28 Jan 2011 04:24:33 +0300 [thread overview]
Message-ID: <20110128042433.7f4758f2@apollo.gnet> (raw)
In-Reply-To: <alpine.DEB.2.00.1101271651250.30861@localhost6.localdomain6>
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В Thu, 27 Jan 2011 16:53:39 -0800 (PST)
Davide Libenzi <davidel@xmailserver.org> пишет:
> 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.
> >
> > <uclibc>/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.
> >
> > <linux>/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.
Yes, but linux/timerfd.h is not installed so timerfd.h from *libc
cannot include it. So adding it to include/linux/Kbuild would be a
first step to make them not hard-code the value. Right?
--
Alexander
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next prev parent reply other threads:[~2011-01-28 1:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-28 0:24 Alexander Gordeev
2011-01-28 0:53 ` Davide Libenzi
2011-01-28 1:24 ` Alexander Gordeev [this message]
2011-01-28 1:49 ` Davide Libenzi
2011-01-28 10:17 ` Alexander Gordeev
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