Re: Fwd: [PATCH 1/1] RDMA/umem: add back hugepage sg list

[Leon Romanovsky <leon@kernel.org>]

On Sun, Mar 07, 2021 at 10:28:33PM +0800, Zhu Yanjun wrote:
> From: Zhu Yanjun <zyjzyj2000@gmail.com>
>
> After the commit ("RDMA/umem: Move to allocate SG table from pages"),
> the sg list from ib_ume_get is like the following:
> "
> sg_dma_address(sg):0x4b3c1ce000
> sg_dma_address(sg):0x4c3c1cd000
> sg_dma_address(sg):0x4d3c1cc000
> sg_dma_address(sg):0x4e3c1cb000
> "
>
> But sometimes, we need sg list like the following:
> "
> sg_dma_address(sg):0x203b400000
> sg_dma_address(sg):0x213b200000
> sg_dma_address(sg):0x223b000000
> sg_dma_address(sg):0x233ae00000
> sg_dma_address(sg):0x243ac00000
> "
> The function ib_umem_add_sg_table can provide the sg list like the
> second. And this function is removed in the commit ("RDMA/umem: Move
> to allocate SG table from pages"). Now I add it back.
>
> The new function is ib_umem_get to ib_umem_hugepage_get that calls
> ib_umem_add_sg_table.
>
> This function ib_umem_huagepage_get can get 4K, 2M sg list dma address.
>
> Fixes: 0c16d9635e3a ("RDMA/umem: Move to allocate SG table from pages")
> Signed-off-by: Zhu Yanjun <zyjzyj2000@gmail.com>
> ---
>  drivers/infiniband/core/umem.c | 197 +++++++++++++++++++++++++++++++++
>  include/rdma/ib_umem.h         |   3 +
>  2 files changed, 200 insertions(+)

You didn't use newly introduced function and didn't really explain why
it is needed.

Thanks