Re: using O_DIRECT to write mmap()'ed IO.

[Michael Honeyfield <mhoneyfield@xxxxxxxxx>]

So, if I read that correctly, the file needs to be block aligned when
its opened? Which is what Arjan said, am I following this right?

Thanks again

Michael.

On 12/16/05, Learner <ruxyz@xxxxxxxxx> wrote:
>
> Checkout this discussion, which maybe of some help to
> you
> http://www.uwsg.iu.edu/hypermail/linux/kernel/0304.1/0400.html
>
> Cheers
>
> --- Michael Honeyfield <mhoneyfield@xxxxxxxxx> wrote:
>
> > Hi all.
> >
> > I am having some troubles with open() O_DIRECT.
> >
> > When trying to write out the contents of a mmap()'ed
> > IO buffer using
> > O_DIRECT, I get a "Bad Address" error. This happens
> > on debian kernels
> > above 2.6.8 and Fedora Core 4 kernels. Like wise
> > with vanilla
> > kernel.org kernels.
> >
> > However, with debian's provided 2.6.8 kernel, there
> > was not such issue.
> >
> > Everything works fine if O_DIRECT is not used. The
> > memery I am workign
> > with is 512 byte aligned.
> >
> > I am unsure and am hoping someone can point me into
> > the right
> > direction. I have spent a fair amount of time on
> > google and review
> > vendor kernels and kernel.org changelogs, but have
> > not seen anything
> > that might help.
> >
> > Thanks in advance.
> >
> > Michael
> >
> > --
> > Kernelnewbies: Help each other learn about the Linux
> > kernel.
> > Archive:
> > http://mail.nl.linux.org/kernelnewbies/
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> >
> >
>
>
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