Re: remove dma_virt_ops v2

Ka-Cheong Poon
2020-11-17T10:53:31Z

On 11/13/20 1:36 AM, santosh.shilimkar@oracle.com wrote:
> + Ka-Cheong
>
> On 11/12/20 5:23 AM, Jason Gunthorpe wrote:
>> On Thu, Nov 12, 2020 at 10:40:30AM +0100, Christoph Hellwig wrote:
>>> ping?
>>>
>>> On Fri, Nov 06, 2020 at 07:19:31PM +0100, Christoph Hellwig wrote:
>>>> Hi Jason,
>>>>
>>>> this series switches the RDMA core to opencode the special case of
>>>> devices bypassing the DMA mapping in the RDMA ULPs.  The virt ops
>>>> have caused a bit of trouble due to the P2P code node working with
>>>> them due to the fact that we'd do two dma mapping iterations for a
>>>> single I/O, but also are a bit of layering violation and lead to
>>>> more code than necessary.
>>>>
>>>> Tested with nvme-rdma over rxe.
>>>>
>>>> Note that the rds changes are untested, as I could not find any
>>>> simple rds test setup.
>>>>
>>>> Changes since v2:
>>>>   - simplify the INFINIBAND_VIRT_DMA dependencies
>>>>   - add a ib_uses_virt_dma helper
>>>>   - use ib_uses_virt_dma in nvmet-rdma to disable p2p for virt_dma devices
>>>>   - use ib_dma_max_seg_size in umem
>>>>   - stop using dmapool in rds
>>>>
>>>> Changes since v1:
>>>>   - disable software RDMA drivers for highmem configs
>>>>   - update the PCI commit logs
>>
>> Santosh can you please check the RDA parts??
>>
>
> Hi Ka-Cheong,
>
> Can you please check Christoph change [1] which clean-up
> dma-pool API to use ib_dma_* and slab allocator ? This was added
> as part of your "net/rds: Use DMA memory pool allocation for rds_header"
> commit.

I applied the patch and ran some basic testing. And it seems to
work fine.

Thanks.

--
K. Poon
ka-cheong.poon@oracle.com