> 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.
>
> Jason
