Re: [PATCH 2/2] powerpc/pseries: Add driver for PAPR SCM regions

[Michael Ellerman <mpe@ellerman.id.au>]

Dan Williams <dan.j.williams@intel.com> writes:
> On Sat, Oct 13, 2018 at 5:08 AM Michael Ellerman <mpe@ellerman.id.au> wrote:
>>
>> Dan Williams <dan.j.williams@intel.com> writes:
>> > On Tue, Oct 9, 2018 at 11:21 PM Oliver O'Halloran <oohall@gmail.com> wrote:
>> >>
>> >> Adds a driver that implements support for enabling and accessing PAPR
>> >> SCM regions. Unfortunately due to how the PAPR interface works we can't
>> >> use the existing of_pmem driver (yet) because:
>> >>
>> ...
>> >> +
>> >> +static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
>> >> +{
>> >> +       struct device *dev = &p->pdev->dev;
>> >> +       struct nd_mapping_desc mapping;
>> >> +       struct nd_region_desc ndr_desc;
>> >> +       unsigned long dimm_flags;
>> >> +
>> >> +       p->bus_desc.ndctl = papr_scm_ndctl;
>> >> +       p->bus_desc.module = THIS_MODULE;
>> >> +       p->bus_desc.of_node = p->pdev->dev.of_node;
>> >> +       p->bus_desc.attr_groups = bus_attr_groups;
>> >> +       p->bus_desc.provider_name = kstrdup(p->pdev->name, GFP_KERNEL);
>> >> +
>> >> +       if (!p->bus_desc.provider_name)
>> >> +               return -ENOMEM;
>> >> +
>> >> +       p->bus = nvdimm_bus_register(NULL, &p->bus_desc);
>> >> +       if (!p->bus) {
>> >> +               dev_err(dev, "Error creating nvdimm bus %pOF\n", p->dn);
>> >> +               return -ENXIO;
>> >> +       }
>> >> +
>> >> +       dimm_flags = 0;
>> >> +       set_bit(NDD_ALIASING, &dimm_flags);
>> >> +
>> >> +       p->nvdimm = nvdimm_create(p->bus, p, papr_scm_dimm_groups,
>> >> +                               dimm_flags, PAPR_SCM_DIMM_CMD_MASK, 0, NULL);
>> >
>> > Looks good, although I'm just about to push out commits that change
>> > this function signature to take a 'security_ops' pointer. If you need
>> > a stable branch to base this on, let me know.
>> ...
>> >
>> > Other than that looks ok to me:
>> >
>> > Acked-by: Dan Williams <dan.j.williams@intel.com>
>> >
>> > ...just the matter of what to do about function signature change.
>>
>> Yeah that's a bit of a bother.
>>
>> The ideal for me would be that you put the commit that changes the
>> signature by itself in a branch based on 4.19-rc3 (or earlier), and then
>> we could both just merge that.
>>
>> But not sure if that will work with whatever else you're trying to sync
>> up with.
>
> How about this, I'll move the new signature to an 'advanced':
>
>     __nvdimm_create()
>
> ...and make the existing:
>
>    nvdimm_create()
>
> ...a simple wrapper around the new functionality. That way no matter
> what merge order we should be ok.

Yep that's much easier, thanks.

cheers
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