Re: [PATCH 2/2] ioatdma: add DMA_PRIVATE capabilities flag

[Dave Jiang]

On 06/18/2013 05:59 PM, Dan Williams wrote:
> On Tue, Jun 18, 2013 at 5:46 PM, Jon Mason <jon.mason@xxxxxxxxx> wrote:
> > Set the DMA_PRIVATE dma_transaction_type in the capability mask.  This
> > enables the ability to get an exclusive ioatdma DMA channel for any
> > devices that requests one via the dma_request_channel function call.
> >
> > Signed-off-by: Jon Mason <jon.mason@xxxxxxxxx>
> > Acked-by: Dave Jiang <dave.jiang@xxxxxxxxx>
> > ---
> >   drivers/dma/ioat/dma_v3.c |    1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
> > index ca6ea9b..ac2aeef 100644
> > --- a/drivers/dma/ioat/dma_v3.c
> > +++ b/drivers/dma/ioat/dma_v3.c
> > @@ -1883,6 +1883,7 @@ int ioat3_dma_probe(struct ioatdma_device *device, int dca)
> >                  dma->copy_align = 6;
> >
> >          dma_cap_set(DMA_INTERRUPT, dma->cap_mask);
> > +       dma_cap_set(DMA_PRIVATE, dma->cap_mask);
> >          dma->device_prep_dma_interrupt = ioat3_prep_interrupt_lock;
> DMA_PRIVATE here keeps all channels private, so they couldn't be used
> elsewhere, for example raid offload.  Do you need a private allocation
> or can you get away with a dynamically assigned channel?
So is there no way to reserve a channel as private if no one is using 
it? It seems the current setup is async_tx or nothing.

--

Dave Jiang
Application Engineer, Storage Divsion
Intel Corp.
dave.jiang@xxxxxxxxx

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