Re: [PATCH v2 1/4] aio: add aio_kernel_() interface

[Christoph Hellwig <hch@infradead.org>]

On Tue, Jan 27, 2015 at 12:18:23AM +0800, Ming Lei wrote:
> > Also it might make sense to just offer aio_kernel_read/write intefaces
> > instead of the common submit wrapper, as that's much closer to other
> > kernel APIs, e.g.
> >
> > int aio_kernel_read(struct kiocb *iocb, struct file *file,
> >                 struct iov_iter *iter, loff_t off,
> >                 void (*complete)(struct kiocb *iocb, long res));
> > int aio_kernel_write(struct kiocb *iocb, struct file *file,
> >                 struct iov_iter *iter, loff_t off,
> >                 void (*complete)(struct kiocb *iocb, long res));
> 
> It is like style of sync APIs, looks submit/complete is common
> for async APIs, like io_submit().

io_submit is a fairly horrible API.  While Posix AIO isn't too much
better it does have separate APIs for read/write.  Given that there
isn't much code shared I'd keep an API that feels familar.