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

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

在 2023/2/15 21:38, Saleem, Shiraz 写道:
>> Subject: [PATCHv3 for-next 1/1] RDMA/irdma: Add support for dmabuf pin
>> memory regions
>>
>> 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.
>> ---
>>   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);
> Do we need this? we don't copy anything from udata. There is no info passed via ABI struct irdma_mem_reg_req.


Got it. I will remove the inlen test and send a new commit out.


>
>> +
>> +	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),
>> --
> Reviewed-by: Shiraz Saleem <shiraz.saleem@intel.com>

Thanks.

Zhu Yanjun

>