Re: [PATCH rdma-next v6 4/4] RDMA/bnxt_re: Direct Verbs: Support CQ and QP verbs

[Jason Gunthorpe <jgg@ziepe.ca>]

On Wed, Dec 24, 2025 at 09:56:02AM +0530, Sriharsha Basavapatna wrote:
> +static struct ib_umem *bnxt_re_dv_umem_get(struct bnxt_re_dev *rdev,
> +					   struct ib_ucontext *ib_uctx,
> +					   int dmabuf_fd,
> +					   u64 addr, u64 size,
> +					   struct bnxt_qplib_sg_info *sg)
> +{
> +	int access = IB_ACCESS_LOCAL_WRITE;
> +	struct ib_umem *umem;
> +	int umem_pgs, rc;
> +
> +	if (dmabuf_fd) {
> +		struct ib_umem_dmabuf *umem_dmabuf;
> +
> +		umem_dmabuf = ib_umem_dmabuf_get_pinned(&rdev->ibdev, addr, size,
> +							dmabuf_fd, access);
> +		if (IS_ERR(umem_dmabuf)) {
> +			rc = PTR_ERR(umem_dmabuf);
> +			goto umem_err;
> +		}
> +		umem = &umem_dmabuf->umem;
> +	} else {
> +		umem = ib_umem_get(&rdev->ibdev, addr, size, access);
> +		if (IS_ERR(umem)) {
> +			rc = PTR_ERR(umem);
> +			goto umem_err;
> +		}
> +	}
> +
> +	umem_pgs = ib_umem_num_dma_blocks(umem, PAGE_SIZE);

I should never see PAGE_SIZE passed to dma_blocks, and you can't call
dma_blocks without previously calling ib_umem_find_best_pgsz() to
validate that the umem is compatible.

I assume you want to use SZ_4K here, as any sizing of the umem should
be derived from absolute hardware capability, never PAGE_SIZE.

Jason