Re: [PATCH v4 for-next 1/1] RDMA/hns: Support direct wqe of userspace

[Leon Romanovsky <leon@kernel.org>]

On Mon, Nov 22, 2021 at 11:38:01AM +0800, Wenpeng Liang wrote:
> From: Yixing Liu <liuyixing1@huawei.com>
> 
> Add direct wqe enable switch and address mapping.
> 
> Signed-off-by: Yixing Liu <liuyixing1@huawei.com>
> Signed-off-by: Wenpeng Liang <liangwenpeng@huawei.com>
> ---
>  drivers/infiniband/hw/hns/hns_roce_device.h |  8 +--
>  drivers/infiniband/hw/hns/hns_roce_main.c   | 38 ++++++++++++---
>  drivers/infiniband/hw/hns/hns_roce_pd.c     |  3 ++
>  drivers/infiniband/hw/hns/hns_roce_qp.c     | 54 ++++++++++++++++++++-
>  include/uapi/rdma/hns-abi.h                 |  2 +
>  5 files changed, 94 insertions(+), 11 deletions(-)

<...>

>  	entry = to_hns_mmap(rdma_entry);
>  	pfn = entry->address >> PAGE_SHIFT;
> -	prot = vma->vm_page_prot;
>  
> -	if (entry->mmap_type != HNS_ROCE_MMAP_TYPE_TPTR)
> -		prot = pgprot_noncached(prot);
> +	switch (entry->mmap_type) {
> +	case HNS_ROCE_MMAP_TYPE_DB:
> +		prot = pgprot_noncached(vma->vm_page_prot);
> +		break;
> +	case HNS_ROCE_MMAP_TYPE_TPTR:
> +		prot = vma->vm_page_prot;
> +		break;
> +	case HNS_ROCE_MMAP_TYPE_DWQE:
> +		prot = pgprot_device(vma->vm_page_prot);

Everything fine, except this pgprot_device(). You probably need to check
WC internally in your driver and use or pgprot_writecombine() or
pgprot_noncached() explicitly.

Thanks