On Fri, Jul 08, 2022 at 03:49:51PM +0100, Matthew Wilcox wrote:
> On Fri, Jul 08, 2022 at 07:45:12AM -0700, Ira Weiny wrote:
> > On Thu, Jul 07, 2022 at 11:06:46AM -0500, Bjorn Helgaas wrote:
> > > On Tue, Jul 05, 2022 at 04:21:58PM -0700, ira.weiny@xxxxxxxxx wrote:
> > > > From: Ira Weiny <ira.weiny@xxxxxxxxx>
> > > >
> > > > The XArray being used to store the protocols does not even store
> > > > allocated objects.
> > >
> > > I guess the point is that the doe_mb->prots XArray doesn't reference
> > > any other objects that would need to be freed when destroying
> > > doe_mb->prots?
> >
> > Yes.
> >
> > > A few more words here would make the commit log more
> > > useful to non-XArray experts.
> >
> > I'll update this to be more clear in a V1 if it goes that far. But to clarify
> > here; the protocol information is a u16 vendor id and u8 protocol number. So
> > we are able to store that in the unsigned long value that would normally be a
> > pointer to something in the XArray.
>
> Er. Signed long.
Sorry I misspoke, xa_mk_value() takes an unsigned long.
> I can't find drivers/pci/doe.c in linux-next, so
> I have no idea if you're doing something wrong.
Sorry doe.c does not exist yet. I came up with this idea while developing a
CXL series which is still in review.[0]
> But what you said here
> sounds wrong.
:-/
Can't I use xa_mk_value() to store data directly in the entry "pointer"?
>From patch 3/9 in that series.[1]
+static void *pci_doe_xa_prot_entry(u16 vid, u8 prot)
+{
+ return xa_mk_value(((unsigned long)vid << 16) | prot);
+}
Both Dan and I thought this was acceptable in XArray?
Ira
[0] https://lore.kernel.org/linux-cxl/20220705154932.2141021-1-ira.weiny@xxxxxxxxx/
[1] https://lore.kernel.org/linux-cxl/20220705154932.2141021-4-ira.weiny@xxxxxxxxx/
