Re: [PATCH v5 4/5] block: loop: prepare for supporing direct IO

[Ming Lei]

On Wed, Jun 10, 2015 at 3:40 PM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> On Tue, Jun 09, 2015 at 09:49:25PM +0800, Ming Lei wrote:
>> This patches provides two approaches for enabling direct IO
>> from user space:
>>
>>       - userspace(such as losetup) can pass 'file' which is
>>       opened/fcntl as O_DIRECT
>>       - sysfs file is provided to run dio tests easily
>
> I really don't think two interfaces are a good idea here.  The interface
> for loop has always been that userspaces passes a FD and we use it,
> so let's keep it that way.

That makes sense.

>
> And while we're at it please also send a patch for losetup so that we
> can actually use the feature.

I have wrote 2 patches to enable direct-io for backing file in util-linux,
and they can be found in below tree:

http://kernel.ubuntu.com/git/ming/util-linux.git/log/?h=losetup-dio

I will post them in util-linux mail list later.

thanks
Ming
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
Please read the FAQ at  http://www.tux.org/lkml/