Re: [PATCH v7 0/5] vfs: Non-blockling buffered fs read (page cache only)

Andrew Morton
2015-03-30T18:54:19Z

On Mon, 30 Mar 2015 00:40:20 -0700 Christoph Hellwig <hch@infradead.org> wrote:

> On Fri, Mar 27, 2015 at 10:04:11AM -0700, Andrew Morton wrote:
> > mm... I don't think we should be adding placeholders to the kernel API
> > to support code which hasn't been written, tested, reviewed, merged,
> > etc. It's possible none of this will ever happen and we end up with a
> > syscall nobody needs or uses. Plus it's always possible that during
> > this development we decide the pwrite2() interface needs alteration but
> > it's too late.
> >
> > What would be the downside of deferring pwrite2() until it's all
> > implemented?
>
> It _is_ implemented. I just decided to submit it separately as Miklos
> already has to deal with enough bikeshedding for his feature that I
> don't want to put the burden of dealing with the BS for the one I wrote
> on him.

afacit the only difference between this pwritev2() and the existing
pwritev() is that pwritev2() interprets pos==-1 as "current position",
which duplicates writev()?

Unless I've missed something, there's no point in merging this
pwritev2() and it would be better to separate this syscall out into a
pwritev2() patchset which can be considered and merged separately. For
the reasons described above.