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

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

在 2023/2/16 23:03, Jason Gunthorpe 写道:
> On Wed, Feb 01, 2023 at 11:21:15AM +0800, Zhu Yanjun wrote:
>> 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>
>> Reviewed-by: Shiraz Saleem <shiraz.saleem@intel.com>
>> ---
>> 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);
> Shiraz is correct, I'm wondering how this even works. This is a new
> style uAPI without UVERBS_ATTR_UHW so inlen should always be 0.

Got it. Thanks Shiraz and Jason.

I will remove the test of inlen in the latest commit.

Best Regards,

Zhu Yanjun

>
> How did you manage to test this??
>
> Jason