> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Thursday, July 16, 2020 9:58 PM
>
> External Email
>
> ----------------------------------------------------------------------
> On Thu, Jul 16, 2020 at 06:17:29PM +0000, Michal Kalderon wrote:
> > > From: linux-rdma-owner@xxxxxxxxxxxxxxx <linux-rdma-
> > > owner@xxxxxxxxxxxxxxx> On Behalf Of Jason Gunthorpe
> > >
> > > On Tue, Jul 07, 2020 at 09:31:00AM +0300, Michal Kalderon wrote:
> > > > User space should receive the maximum edpm size from kernel
> > > > driver, similar to other edpm/ldpm related limits.
> > > > Add an additional parameter to the alloc_ucontext_resp structure
> > > > for the edpm maximum size.
> > > >
> > > > In addition, pass an indication from user-space to kernel (and not
> > > > just kernel to user) that the DPM sizes are supported.
> > > >
> > > > This is for supporting backward-forward compatibility between
> > > > driver and lib for everything related to DPM transaction and limit sizes.
> > > >
> > > > This should have been part of commit mentioned in Fixes tag.
> > > > Fixes: 93a3d05f9d68 ("RDMA/qedr: Add kernel capability flags for
> > > > dpm enabled mode")
> > > > Signed-off-by: Ariel Elior <ariel.elior@xxxxxxxxxxx>
> > > > Signed-off-by: Michal Kalderon <michal.kalderon@xxxxxxxxxxx>
> > > > drivers/infiniband/hw/qedr/verbs.c | 9 ++++++---
> > > > include/uapi/rdma/qedr-abi.h | 6 +++++-
> > > > 2 files changed, 11 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/infiniband/hw/qedr/verbs.c
> > > > b/drivers/infiniband/hw/qedr/verbs.c
> > > > index fbb0c66c7f2c..cfe4cd637f1c 100644
> > > > +++ b/drivers/infiniband/hw/qedr/verbs.c
> > > > @@ -320,9 +320,12 @@ int qedr_alloc_ucontext(struct ib_ucontext
> > > > *uctx,
> > > struct ib_udata *udata)
> > > > QEDR_DPM_TYPE_ROCE_LEGACY |
> > > > QEDR_DPM_TYPE_ROCE_EDPM_MODE;
> > > >
> > > > - uresp.dpm_flags |= QEDR_DPM_SIZES_SET;
> > > > - uresp.ldpm_limit_size = QEDR_LDPM_MAX_SIZE;
> > > > - uresp.edpm_trans_size = QEDR_EDPM_TRANS_SIZE;
> > > > + if (ureq.context_flags & QEDR_SUPPORT_DPM_SIZES) {
> > >
> > > Why does this need an input flag just to set some outputs?
> > >
> > > The usual truncate on not enough size should take care of it, right?
> > At this point it just sets some output, but for future related changes
> > around these sizes there will also be fw related configurations, we
> > will need to know whether the lib supports accepting different sizes
> > or not. This is for forward compatibility between libqedr and driver.
>
> I would be happier to see this flag introduced when it actually had a purpose,
> as I really don't like the pattern of conditionally filling uresp, but OK. Please
> delete this if when you make use of it the flag properly.
Sure, thanks.
>
> Jason
