Re: [PATCH v2 11/13] NTB: convert to dmaengine_unmap_data

From: Jon Mason
Date: Tue Oct 22 2013 - 21:18:41 EST


On Tue, Oct 22, 2013 at 06:05:31PM -0700, Dan Williams wrote:
> On Tue, Oct 22, 2013 at 4:12 PM, Jon Mason <jon.mason@xxxxxxxxx> wrote:
> > On Tue, Oct 22, 2013 at 02:29:36PM -0700, Dan Williams wrote:
> >> On Fri, Oct 18, 2013 at 6:06 PM, Jon Mason <jon.mason@xxxxxxxxx> wrote:
> >> > On Fri, Oct 18, 2013 at 07:35:31PM +0200, Bartlomiej Zolnierkiewicz wrote:
> >> >> Use the generic unmap object to unmap dma buffers.
> >> >>
> >> >> As NTB can be compiled without DMA_ENGINE support add
> >> >
> >> > Seems like the stubs should be added outside of this patch.
> >>
> >> I think they are ok here as this is the only driver that uses them.
> >> The alternative is a new api patch without a user.
> >>
> >> > Also, the
> >> > comment implies that NTB could not be compiled without DMA_ENGINE
> >> > support before, which it could be.
> >>
> >> Hmm, I read it as "since NTB *can* be compiled without dmaengine here
> >> are some stubs".
> >
> > This poses an overall question of whether it would simply be better to
> > abstract all of the with/without DMA_ENGINE part and simply remap it
> > to memcpy if DMA_ENGINE is not set (or if the DMA engine is
> > hotplugged). Of course, this is outside the scope of this patch.
>
> That's at least the promise of async_memcpy() it does not care if a
> channel is there or not, but I think it is better if the client has a
> strict dma and non-dma path. Hiding the dma details from the client
> seems to have been the wrong choice at least for raid.
>
> > That is fine. It can be like this in the short term.
> >
> > Thanks,
> > Jon
>
> I'll take that as:
>
> Acked-by: Jon Mason <jon.mason@xxxxxxxxx>

Begrudgingly-Acked-by: Jon Mason <jon.mason@xxxxxxxxx>

>
> ...but holler if not.
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