Re: [PATCH for-next v6 6/7] RDMA/rxe: Add support for Send/Recv/Write/Read with ODP

[Jason Gunthorpe]

On Fri, Sep 08, 2023 at 03:26:47PM +0900, Daisuke Matsuda wrote:
> +static inline bool rxe_odp_check_pages(struct rxe_mr *mr, u64 iova,
> +				       int length, u32 flags)
> +{
> +	unsigned long lower, upper, idx;
> +	unsigned long hmm_flags = HMM_PFN_VALID;
> +	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
> +	struct page *page;
> +	bool need_fault = false;
> +
> +	lower = rxe_mr_iova_to_index(mr, iova);
> +	upper = rxe_mr_iova_to_index(mr, iova + length - 1);
> +
> +	if (!(flags & RXE_PAGEFAULT_RDONLY))
> +		hmm_flags |= HMM_PFN_WRITE;
> +
> +	/* xarray is protected by umem_mutex */
> +	for (idx = lower; idx <= upper; idx++) {
> +		page = xa_load(&mr->page_list, idx);
> +
> +		if (!page || !(umem_odp->pfn_list[idx] & hmm_flags)) {
> +			need_fault = true;

Again you don't need the pfn_list and rxe should perhaps ideally find
some way to disable it since we store struct pages in the xarray.

This could also be a xas loop

Jason