Re: [PATCH for-next 1/1] RDMA/hns: Add a new mmap implementation

[Jason Gunthorpe <jgg@nvidia.com>]

On Thu, Sep 30, 2021 at 04:36:08PM +0800, Wenpeng Liang wrote:
> From: Chengchang Tang <tangchengchang@huawei.com>
> 
> Add a new implementation for mmap by using the new mmap entry API.
> 
> The new implementation prepares for subsequent features and is compatible
> with the old implementation. And the old implementation using hard-coded
> offset will not be extended in the future.
> 
> Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
> Signed-off-by: Wenpeng Liang <liangwenpeng@huawei.com>
>  drivers/infiniband/hw/hns/hns_roce_device.h |  21 +++
>  drivers/infiniband/hw/hns/hns_roce_main.c   | 148 +++++++++++++++++++-
>  include/uapi/rdma/hns-abi.h                 |  21 ++-
>  3 files changed, 184 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/hns/hns_roce_device.h b/drivers/infiniband/hw/hns/hns_roce_device.h
> index 9467c39e3d28..ca456948b2d8 100644
> +++ b/drivers/infiniband/hw/hns/hns_roce_device.h
> @@ -225,11 +225,23 @@ struct hns_roce_uar {
>  	unsigned long	logic_idx;
>  };
>  
> +struct hns_user_mmap_entry {
> +	struct rdma_user_mmap_entry rdma_entry;
> +	u64 address;
> +	u8 mmap_flag;
> +};
> +
> +enum hns_roce_mmap_type {
> +	HNS_ROCE_MMAP_TYPE_DB = 1,
> +};
> +
>  struct hns_roce_ucontext {
>  	struct ib_ucontext	ibucontext;
>  	struct hns_roce_uar	uar;
>  	struct list_head	page_list;
>  	struct mutex		page_mutex;
> +	bool			mmap_key_support;
> +	struct rdma_user_mmap_entry *db_mmap_entry;

This should be struct hns_user_mmap_entry


> +struct rdma_user_mmap_entry *hns_roce_user_mmap_entry_insert(
> +			struct ib_ucontext *ucontext, u64 address,
> +			size_t length, u8 mmap_flag)

And this should return the hns_user_mmap_entry too

> +static void ucontext_get_config(struct hns_roce_ucontext *context,
> +				struct hns_roce_ib_alloc_ucontext *ucmd)
> +{
> +	struct hns_roce_dev *hr_dev = to_hr_dev(context->ibucontext.device);
> +
> +	if (ucmd->comp & HNS_ROCE_ALLOC_UCTX_COMP_CONFIG &&
> +	    hr_dev->hw_rev != HNS_ROCE_HW_VER1)
> +		context->mmap_key_support = !!(ucmd->config &
> +					       HNS_ROCE_UCTX_REQ_MMAP_KEY_EN);

No need for !! when in a bool context

>  
> +static int hns_roce_mmap(struct ib_ucontext *uctx, struct vm_area_struct *vma)
> +{
> +	struct hns_roce_ucontext *context = to_hr_ucontext(uctx);
> +	struct hns_roce_dev *hr_dev = to_hr_dev(uctx->device);
> +	struct ib_device *ibdev = &hr_dev->ib_dev;
> +	struct rdma_user_mmap_entry *rdma_entry;
> +	struct hns_user_mmap_entry *entry;
> +	phys_addr_t pfn;
> +	pgprot_t prot;
> +	int ret;
> +
> +	if (!context->mmap_key_support)
> +		return hns_roce_legacy_mmap(uctx, vma);

This shouldn't be necessary,

Just call rdma_user_mmap_entry_insert_range() to insert the two pages
at 0 and 1 when in legacy mode and always keep the mmap routine in new
mode

Jason