Re: [PATCHv3 for-next 1/1] RDMA/irdma: Add support for dmabuf pin memory regions

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2023/2/1 11:21, Zhu Yanjun 写道:
> From: Zhu Yanjun <yanjun.zhu@linux.dev>
> 
> This is a followup to the EFA dmabuf[1]. Irdma driver currently does
> not support on-demand-paging(ODP). So it uses habanalabs as the
> dmabuf exporter, and irdma as the importer to allow for peer2peer
> access through libibverbs.
> 
> In this commit, the function ib_umem_dmabuf_get_pinned() is used.
> This function is introduced in EFA dmabuf[1] which allows the driver
> to get a dmabuf umem which is pinned and does not require move_notify
> callback implementation. The returned umem is pinned and DMA mapped
> like standard cpu umems, and is released through ib_umem_release().
> 
> [1]https://lore.kernel.org/lkml/20211007114018.GD2688930@ziepe.ca/t/
> 
> Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
> ---
> V2->V3: Remove unnecessary variable initialization;
>          Use error handler;
> V1->V2: Thanks Shiraz Saleem, he gave me a lot of good suggestions.
>          This commit is based on the shared functions from refactored
>          irdma_reg_user_mr.

Shiraz Saleem is on vacation and returning to office on Feb.13, 2023.
We can wait for him.

Zhu Yanjun

> ---
>   drivers/infiniband/hw/irdma/verbs.c | 45 +++++++++++++++++++++++++++++
>   1 file changed, 45 insertions(+)
> 
> diff --git a/drivers/infiniband/hw/irdma/verbs.c b/drivers/infiniband/hw/irdma/verbs.c
> index 6982f38596c8..7525f4cdf6fb 100644
> --- a/drivers/infiniband/hw/irdma/verbs.c
> +++ b/drivers/infiniband/hw/irdma/verbs.c
> @@ -2977,6 +2977,50 @@ static struct ib_mr *irdma_reg_user_mr(struct ib_pd *pd, u64 start, u64 len,
>   	return ERR_PTR(err);
>   }
>   
> +static struct ib_mr *irdma_reg_user_mr_dmabuf(struct ib_pd *pd, u64 start,
> +					      u64 len, u64 virt,
> +					      int fd, int access,
> +					      struct ib_udata *udata)
> +{
> +	struct irdma_device *iwdev = to_iwdev(pd->device);
> +	struct ib_umem_dmabuf *umem_dmabuf;
> +	struct irdma_mr *iwmr;
> +	int err;
> +
> +	if (len > iwdev->rf->sc_dev.hw_attrs.max_mr_size)
> +		return ERR_PTR(-EINVAL);
> +
> +	if (udata->inlen < IRDMA_MEM_REG_MIN_REQ_LEN)
> +		return ERR_PTR(-EINVAL);
> +
> +	umem_dmabuf = ib_umem_dmabuf_get_pinned(pd->device, start, len, fd, access);
> +	if (IS_ERR(umem_dmabuf)) {
> +		err = PTR_ERR(umem_dmabuf);
> +		ibdev_dbg(&iwdev->ibdev, "Failed to get dmabuf umem[%d]\n", err);
> +		return ERR_PTR(err);
> +	}
> +
> +	iwmr = irdma_alloc_iwmr(&umem_dmabuf->umem, pd, virt, IRDMA_MEMREG_TYPE_MEM);
> +	if (IS_ERR(iwmr)) {
> +		err = PTR_ERR(iwmr);
> +		goto err_release;
> +	}
> +
> +	err = irdma_reg_user_mr_type_mem(iwmr, access);
> +	if (err)
> +		goto err_iwmr;
> +
> +	return &iwmr->ibmr;
> +
> +err_iwmr:
> +	irdma_free_iwmr(iwmr);
> +
> +err_release:
> +	ib_umem_release(&umem_dmabuf->umem);
> +
> +	return ERR_PTR(err);
> +}
> +
>   /**
>    * irdma_reg_phys_mr - register kernel physical memory
>    * @pd: ibpd pointer
> @@ -4483,6 +4527,7 @@ static const struct ib_device_ops irdma_dev_ops = {
>   	.query_port = irdma_query_port,
>   	.query_qp = irdma_query_qp,
>   	.reg_user_mr = irdma_reg_user_mr,
> +	.reg_user_mr_dmabuf = irdma_reg_user_mr_dmabuf,
>   	.req_notify_cq = irdma_req_notify_cq,
>   	.resize_cq = irdma_resize_cq,
>   	INIT_RDMA_OBJ_SIZE(ib_pd, irdma_pd, ibpd),