Re: [PATCH] [14/20] Don't disable direct_io for unchecked_isa_dma in st.c

[Jens Axboe <jens.axboe@oracle.com>]

On Sun, Mar 16 2008, Andi Kleen wrote:
> On Sun, Mar 16, 2008 at 02:39:19PM +0200, Boaz Harrosh wrote:
> > On Fri, Mar 14 2008 at 16:24 +0200, Christoph Hellwig <hch@infradead.org> wrote:
> > > On Fri, Mar 14, 2008 at 02:51:35PM +0100, Jens Axboe wrote:
> > >> Are you sure? Seems to me that st builds its own list with
> > >> get_user_pages() for direct io, where will that get bounced? The block
> > >> layer will only bounce things that are mapped directly, so if st used
> > >> blk_rq_map_kern() and inserted that request in the queue, we could
> > >> proceed with killing that check in st.
> > > 
> > > Which shouldn't be all too difficult and would be the right thing to
> > > do.  We really need someone to sit down and convert st/osst/sg to use
> > > the proper block layer helpers.
> > > 
> > 
> > First they do. They all call scsi_execute_async which at the end produces
> > a BIO and then calls blk_execute_nowait(). and all is swell.
> 
> I thought i had audited them all too, but wasn't 100% sure anymore.
> But thanks for double checking.
> 
> Jens, that answers your earlier question.

OK good, I didn't realize that that path was already done. No problem
with this part, then.

-- 
Jens Axboe