[v2] mm: numa_memblks: introduce numa_add_reserved_memblk

acpi_parse_cfmws() currently adds empty CFMWS ranges to numa_meminfo
with the expectation that numa_cleanup_meminfo moves them to
numa_reserved_meminfo. There is no need for that indirection when it is
known in advance that these unpopulated ranges are meant for
numa_reserved_meminfo in support of future hotplug / CXL provisioning.

Introduce and use numa_add_reserved_memblk() to add the empty CFMWS
ranges directly.

Signed-off-by: Yuquan Wang <wangyuquan1236@phytium.com.cn>
---

Changes in v2 (Thanks to Dan & Alison):
- Use numa_add_reserved_memblk() to replace numa_add_memblk() in acpi_parse_cfmws()
- Add comments to describe the usage of numa_add_reserved_memblk()
- Updating the commit message to clarify the purpose of the patch

By the way, "LoongArch: Introduce the numa_memblks conversion" is in linux-next.

 drivers/acpi/numa/srat.c     |  2 +-
 include/linux/numa_memblks.h |  1 +
 mm/numa_memblks.c            | 22 ++++++++++++++++++++++
 3 files changed, 24 insertions(+), 1 deletion(-)

On Wed, May 07, 2025 at 05:24:36PM +0100, Jonathan Cameron wrote:
> On Tue, 6 May 2025 14:22:45 +0800
> Yuquan Wang <wangyuquan1236@phytium.com.cn> wrote:
> 
> > acpi_parse_cfmws() currently adds empty CFMWS ranges to numa_meminfo
> > with the expectation that numa_cleanup_meminfo moves them to
> > numa_reserved_meminfo. There is no need for that indirection when it is
> > known in advance that these unpopulated ranges are meant for
> > numa_reserved_meminfo in support of future hotplug / CXL provisioning.
> > 
> > Introduce and use numa_add_reserved_memblk() to add the empty CFMWS
> > ranges directly.
> > 
> > Signed-off-by: Yuquan Wang <wangyuquan1236@phytium.com.cn>
> This is v2 take 2.  There were tags on the previous version (pre longarch
> change).
> 
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 
> (Also Dan Williams).
> 
> Easiest option when this happens is spin a v3 with a change log to
> say the loongarch issue is resolved and you picked up tags.
>
Hi Jonathan,

Thanks for your tips. Would this v2 version trigger the kernel test
robot? It seems like only a new version of patch would trigger that.
I would publish v3 of this patch as soon as possible. 

Yuquan
> 
> > ---
> > 
> > Changes in v2 (Thanks to Dan & Alison):
> > - Use numa_add_reserved_memblk() to replace numa_add_memblk() in acpi_parse_cfmws()
> > - Add comments to describe the usage of numa_add_reserved_memblk()
> > - Updating the commit message to clarify the purpose of the patch
> > 
> > By the way, "LoongArch: Introduce the numa_memblks conversion" is in linux-next.
> > 
> >  drivers/acpi/numa/srat.c     |  2 +-
> >  include/linux/numa_memblks.h |  1 +
> >  mm/numa_memblks.c            | 22 ++++++++++++++++++++++
> >  3 files changed, 24 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
> > index 0a725e46d017..751774f0b4e5 100644
> > --- a/drivers/acpi/numa/srat.c
> > +++ b/drivers/acpi/numa/srat.c
> > @@ -453,7 +453,7 @@ static int __init acpi_parse_cfmws(union acpi_subtable_headers *header,
> >  		return -EINVAL;
> >  	}
> >  
> > -	if (numa_add_memblk(node, start, end) < 0) {
> > +	if (numa_add_reserved_memblk(node, start, end) < 0) {
> >  		/* CXL driver must handle the NUMA_NO_NODE case */
> >  		pr_warn("ACPI NUMA: Failed to add memblk for CFMWS node %d [mem %#llx-%#llx]\n",
> >  			node, start, end);
> > diff --git a/include/linux/numa_memblks.h b/include/linux/numa_memblks.h
> > index dd85613cdd86..991076cba7c5 100644
> > --- a/include/linux/numa_memblks.h
> > +++ b/include/linux/numa_memblks.h
> > @@ -22,6 +22,7 @@ struct numa_meminfo {
> >  };
> >  
> >  int __init numa_add_memblk(int nodeid, u64 start, u64 end);
> > +int __init numa_add_reserved_memblk(int nid, u64 start, u64 end);
> >  void __init numa_remove_memblk_from(int idx, struct numa_meminfo *mi);
> >  
> >  int __init numa_cleanup_meminfo(struct numa_meminfo *mi);
> > diff --git a/mm/numa_memblks.c b/mm/numa_memblks.c
> > index ff4054f4334d..541a99c4071a 100644
> > --- a/mm/numa_memblks.c
> > +++ b/mm/numa_memblks.c
> > @@ -200,6 +200,28 @@ int __init numa_add_memblk(int nid, u64 start, u64 end)
> >  	return numa_add_memblk_to(nid, start, end, &numa_meminfo);
> >  }
> >  
> > +/**
> > + * numa_add_reserved_memblk - Add one numa_memblk to numa_reserved_meminfo
> > + * @nid: NUMA node ID of the new memblk
> > + * @start: Start address of the new memblk
> > + * @end: End address of the new memblk
> > + *
> > + * Add a new memblk to the numa_reserved_meminfo.
> > + *
> > + * Usage Case: numa_cleanup_meminfo() reconciles all numa_memblk instances
> > + * against memblock_type information and moves any that intersect reserved
> > + * ranges to numa_reserved_meminfo. However, when that information is known
> > + * ahead of time, we use numa_add_reserved_memblk() to add the numa_memblk
> > + * to numa_reserved_meminfo directly.
> > + *
> > + * RETURNS:
> > + * 0 on success, -errno on failure.
> > + */
> > +int __init numa_add_reserved_memblk(int nid, u64 start, u64 end)
> > +{
> > +	return numa_add_memblk_to(nid, start, end, &numa_reserved_meminfo);
> > +}
> > +
> >  /**
> >   * numa_cleanup_meminfo - Cleanup a numa_meminfo
> >   * @mi: numa_meminfo to clean up
>