Re: [PATCH -mm 3/10][RFC] aio: use iov_length instead of ki_left

[Ingo Oeser]

On Tuesday, 16. January 2007 06:37, Nate Diller wrote:
> On 1/15/07, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> > On Mon, Jan 15, 2007 at 05:54:50PM -0800, Nate Diller wrote:
> > > Convert code using iocb->ki_left to use the more generic iov_length() call.
> >
> > No way.  We need to reduce the numer of iovec traversals, not adding
> > more of them.
> 
> ok, I can work on a version of this that uses struct iodesc.  Maybe
> something like this?
> 
> struct iodesc {
>         struct iovec *iov;
>         unsigned long nr_segs;
>         size_t nbytes;
> };
> 
> I suppose it's worth doing the iodesc thing along with this patchset
> anyway, since it'll avoid an extra round of interface churn.

What about this instead

struct iodesc {
	struct iovec *iov;
	unsigned long nr_segs;
	unsigned long seg_limit;
	size_t nr_bytes;
};

That will enable resizeable iodescs with partial completion state and
will enable successive filling of an iodesc with iovs.

This will be needed anyway. I built an complete short userspace 
module for that already. I can post and GPLv2 it somewhere, if people
are interested.

Regards

Ingo Oeser
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