>
> On Tue, Feb 27, 2018 at 04:21:36PM -0600, Steve Wise wrote:
> > >
> > > On Mon, Feb 26, 2018 at 03:22:42PM -0800, Steve Wise wrote:
> > >
> > > > +static int fill_res_mr_entry(struct sk_buff *msg, struct
> > netlink_callback
> > > *cb,
> > > > + struct rdma_restrack_entry *res,
uint32_t port)
> > > > +{
> > > > + struct ib_mr *mr = container_of(res, struct ib_mr, res);
> > > > + struct nlattr *entry_attr;
> > > > +
> > > > + entry_attr = nla_nest_start(msg,
> > > RDMA_NLDEV_ATTR_RES_MR_ENTRY);
> > > > + if (!entry_attr)
> > > > + goto out;
> > > > +
> > > > + if (netlink_capable(cb->skb, CAP_NET_ADMIN)) {
> > > > + if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_RKEY, mr-
> > > >rkey))
> > > > + goto err;
> > > > + if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_LKEY, mr-
> > > >lkey))
> > > > + goto err;
> > > > + if (nla_put_u64_64bit(msg, RDMA_NLDEV_ATTR_RES_IOVA,
> > > > + mr->iova, 0))
> > >
> > > ?? is '0' right here? Expecting a defined attribute constant for
padding.
> >
> >
> > What does the pad do exactly? I replicated other code I saw that use 0
for
> > the pad. But I can add a NLDEV_ATTR_RES_PAD if that is the correct way
to
> > go.
>
> Sometimes netlink will try to align the u64s to 8 bytes in the skb. If
> it needs to make an alignment adjustment then it stuffs a dummy
> attribute with the given ID. The ID should never be used for any other
> attribute and must be ignored by userspace.
>
> Safest to put it in the general enum to ensure it isn't re-used.
>
> > > > + if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_PGSIZE, mr-
> > > >page_size))
> > > > + goto err;
> > >
> > > Still not really sure what pgsize is supposed to be, I think we should
> > > drop it??
> > >
> >
> > Let us say we register a MR that has a backing memory scattergather list
of
> > 10 64KB entries, each 64KB entry, though, is physically contiguous.
The
> > page-size for that registration, then can be 64KB even though the host
page
> > size is 4KB. So the page list for the registration with the rdma device
can
> > be 10 64K entries, each of size 64KB...
>
> So what is the value?
>
> 'max contiguous page size' of any page in the registration or 'min
> contiguous page size' of any page in the registration?
>
> Seems like it needs a better name at least..
>
> Jason
All "pages" in the REG_MR page list are of the same size. So pgsize is the
size of each entry...
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