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Date: Fri, 29 Apr 2016 11:25:15 +0800
From: Fam Zheng <famz@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v2 03/17] block: Support AIO drivers in
 bdrv_driver_preadv/pwritev()
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To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-devel@nongnu.org, sw@weilnetz.de, stefanha@redhat.com, qemu-block@nongnu.org, mreitz@redhat.com

On Fri, 04/29 09:22, Fam Zheng wrote:
> > @@ -125,19 +119,13 @@ void bdrv_io_limits_update_group(BlockDriverState *bs, const char *group)
> >  
> >  void bdrv_setup_io_funcs(BlockDriver *bdrv)
> >  {
> > -    /* Block drivers without coroutine functions need emulation */
> > -    if (!bdrv->bdrv_co_readv) {
> > -        bdrv->bdrv_co_readv = bdrv_co_readv_em;
> > -        bdrv->bdrv_co_writev = bdrv_co_writev_em;
> > -
> > -        /* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if
> > -         * the block driver lacks aio we need to emulate that too.
> > -         */
> > -        if (!bdrv->bdrv_aio_readv) {
> > -            /* add AIO emulation layer */
> > -            bdrv->bdrv_aio_readv = bdrv_aio_readv_em;
> > -            bdrv->bdrv_aio_writev = bdrv_aio_writev_em;
> > -        }
> > +    /* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if
> > +     * the block driver lacks aio we need to emulate that.
> > +     */
> > +    if (!bdrv->bdrv_aio_readv) {
> 
> I'd also AND with !bdrv->bdrv_co_readv, because in that case the em functions
> are assigned but not used.

Never mind, I see the last patch removes this altogether.

Fam