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

[Jason Gunthorpe <jgg@nvidia.com>]

On Fri, Feb 17, 2023 at 08:46:52AM +0800, Zhu Yanjun wrote:
> 
> 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.

Please answer how did you manage to test this?

Jason