Re: [Qemu-devel] [PATCH 05/10] xen: add block device backend driver.

[Christoph Hellwig <hch@lst.de>]

On Tue, Apr 07, 2009 at 12:22:00PM +0200, Gerd Hoffmann wrote:
>   Hi,
> 
> >We already have bdrv_aio_readv/writev which currently linearize the
> >buffer underneath.  Hopefully Anthony will have commited the patch to
> >implement the real one while I'm writing this, too :)
> 
> Is there any specific reason to keep the nb_sectors argument for 
> bdrv_aio_readv, other than cut&paste from the non-vectored versions?
> I think it is superfluous now, it can be trivially calculated using 
> iov->size.

For the functions in block.c I want to keep them the same as they were
before, and for the methods I want to keep the signature the same as
the exported wrappers.

All this is going to change pretty soon I hope, we'll need another
argument to bdrv_aio_write for barrier writes, and I might switch to
a completely byte based interface for the aio requests with flags
in the block driver state for flagging the alignment restrictions.