From: Davide Libenzi <davidel@xmailserver.org>
To: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Cc: uClibc <uclibc@uclibc.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: timerfd incompatibility on mips
Date: Thu, 27 Jan 2011 16:53:39 -0800 (PST) [thread overview]
Message-ID: <alpine.DEB.2.00.1101271651250.30861@localhost6.localdomain6> (raw)
In-Reply-To: <20110128032443.6f8b877e@apollo.gnet>
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.
- Davide
next prev parent reply other threads:[~2011-01-28 0:53 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 [this message]
2011-01-28 1:24 ` Alexander Gordeev
2011-01-28 1:49 ` Davide Libenzi
2011-01-28 10:17 ` Alexander Gordeev
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