Re: [PATCH V2 05/20] nvdimm/region_label: Add region label updation routine

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Wed, 30 Jul 2025 17:41:54 +0530
Neeraj Kumar <s.neeraj@samsung.com> wrote:

> Added __pmem_region_label_update region label update routine to update
> region label.
> 
> Also used guard(mutex)(&nd_mapping->lock) in place of mutex_lock() and
> mutex_unlock()
> 
> Signed-off-by: Neeraj Kumar <s.neeraj@samsung.com>

A few comments inline,

Thanks,

Jonathan


>  static bool slot_valid(struct nvdimm_drvdata *ndd,
>  		struct nd_lsa_label *lsa_label, u32 slot)
>  {
> @@ -960,7 +970,7 @@ static int __pmem_label_update(struct nd_region *nd_region,
>  		return rc;
>  
>  	/* Garbage collect the previous label */
> -	mutex_lock(&nd_mapping->lock);
> +	guard(mutex)(&nd_mapping->lock);
>  	list_for_each_entry(label_ent, &nd_mapping->labels, list) {
>  		if (!label_ent->label)
>  			continue;
> @@ -972,20 +982,20 @@ static int __pmem_label_update(struct nd_region *nd_region,
>  	/* update index */
>  	rc = nd_label_write_index(ndd, ndd->ns_next,
>  			nd_inc_seq(__le32_to_cpu(nsindex->seq)), 0);
> -	if (rc == 0) {
> -		list_for_each_entry(label_ent, &nd_mapping->labels, list)
> -			if (!label_ent->label) {
> -				label_ent->label = lsa_label;
> -				lsa_label = NULL;
> -				break;
> -			}
> -		dev_WARN_ONCE(&nspm->nsio.common.dev, lsa_label,
> -				"failed to track label: %d\n",
> -				to_slot(ndd, lsa_label));
> -		if (lsa_label)
> -			rc = -ENXIO;
> -	}
> -	mutex_unlock(&nd_mapping->lock);
> +	if (rc)
> +		return rc;
> +
> +	list_for_each_entry(label_ent, &nd_mapping->labels, list)
> +		if (!label_ent->label) {
> +			label_ent->label = lsa_label;
> +			lsa_label = NULL;
> +			break;
> +		}
> +	dev_WARN_ONCE(&nspm->nsio.common.dev, lsa_label,
> +			"failed to track label: %d\n",
> +			to_slot(ndd, lsa_label));
> +	if (lsa_label)
> +		rc = -ENXIO;
	if (lsa_label)
		return -ENXIO;

	return 0;

is a little clearer.

>  
>  	return rc;
>  }
> @@ -1127,6 +1137,137 @@ int nd_pmem_namespace_label_update(struct nd_region *nd_region,
>  	return 0;
>  }
>  
> +static int __pmem_region_label_update(struct nd_region *nd_region,
> +		struct nd_mapping *nd_mapping, int pos, unsigned long flags)
> +{
> +	struct nd_interleave_set *nd_set = nd_region->nd_set;
> +	struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
> +	struct nd_lsa_label *nd_label;
> +	struct cxl_region_label *rg_label;
> +	struct nd_namespace_index *nsindex;
> +	struct nd_label_ent *label_ent;
> +	unsigned long *free;
> +	u32 nslot, slot;
> +	size_t offset;
> +	int rc;
> +	uuid_t tmp;
> +
> +	if (!preamble_next(ndd, &nsindex, &free, &nslot))
> +		return -ENXIO;
> +
> +	/* allocate and write the label to the staging (next) index */
> +	slot = nd_label_alloc_slot(ndd);
> +	if (slot == UINT_MAX)
> +		return -ENXIO;
> +	dev_dbg(ndd->dev, "allocated: %d\n", slot);
> +
> +	nd_label = to_label(ndd, slot);
> +
> +	memset(nd_label, 0, sizeof_namespace_label(ndd));
> +	rg_label = &nd_label->rg_label;
> +
> +	/* Set Region Label Format identification UUID */
> +	uuid_parse(CXL_REGION_UUID, &tmp);
> +	export_uuid(nd_label->rg_label.type, &tmp);

	export_uuid(rg_label->type, &tmp);

> +
> +	/* Set Current Region Label UUID */
> +	export_uuid(nd_label->rg_label.uuid, &nd_set->uuid);

	export_uuid(rg_label->uuid, &nd_set->uuid);


> +
> +	rg_label->flags = __cpu_to_le32(flags);
> +	rg_label->nlabel = __cpu_to_le16(nd_region->ndr_mappings);
> +	rg_label->position = __cpu_to_le16(pos);
> +	rg_label->dpa = __cpu_to_le64(nd_mapping->start);
> +	rg_label->rawsize = __cpu_to_le64(nd_mapping->size);
> +	rg_label->hpa = __cpu_to_le64(nd_set->res->start);
> +	rg_label->slot = __cpu_to_le32(slot);
> +	rg_label->ig = __cpu_to_le32(nd_set->interleave_granularity);
> +	rg_label->align = __cpu_to_le16(0);

As the bot complained... It's le32

> +
> +	/* Update fletcher64 Checksum */
> +	rgl_calculate_checksum(ndd, rg_label);
> +
> +	/* update label */
> +	offset = nd_label_offset(ndd, nd_label);
> +	rc = nvdimm_set_config_data(ndd, offset, nd_label,
> +			sizeof_namespace_label(ndd));
> +	if (rc < 0) {
> +		nd_label_free_slot(ndd, slot);
> +		return rc;
> +	}
> +
> +	/* Garbage collect the previous label */
> +	guard(mutex)(&nd_mapping->lock);
> +	list_for_each_entry(label_ent, &nd_mapping->labels, list) {
> +		if (!label_ent->label)
> +			continue;
> +		if (rgl_uuid_equal(&label_ent->label->rg_label, &nd_set->uuid))
> +			reap_victim(nd_mapping, label_ent);
> +	}
> +
> +	/* update index */
> +	rc = nd_label_write_index(ndd, ndd->ns_next,
> +			nd_inc_seq(__le32_to_cpu(nsindex->seq)), 0);
> +	if (rc)
> +		return rc;
> +
> +	list_for_each_entry(label_ent, &nd_mapping->labels, list)
> +		if (!label_ent->label) {
> +			label_ent->label = nd_label;
> +			nd_label = NULL;
> +			break;
> +		}
> +	dev_WARN_ONCE(&nd_region->dev, nd_label,
> +			"failed to track label: %d\n",
> +			to_slot(ndd, nd_label));
> +	if (nd_label)
> +		rc = -ENXIO;

		return -ENXIO;

> +

	return 0;

is clearer.

> +	return rc;
> +}
> +
> +int nd_pmem_region_label_update(struct nd_region *nd_region)
> +{
> +	int i, rc;
> +
> +	for (i = 0; i < nd_region->ndr_mappings; i++) {
> +		struct nd_mapping *nd_mapping = &nd_region->mapping[i];
> +		struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
> +
> +		/* No need to update region label for non cxl format */
> +		if (!ndd->cxl)
> +			continue;
> +
> +		/* Init labels to include region label */
> +		rc = init_labels(nd_mapping, 1);
> +

No blank line here - keep the error check closely associated with the
thing that it is checking.

> +		if (rc < 0)
> +			return rc;
> +
> +		rc = __pmem_region_label_update(nd_region, nd_mapping, i,
> +					NSLABEL_FLAG_UPDATING);
> +

Same here.

> +		if (rc)
> +			return rc;
> +	}
> +
> +	/* Clear the UPDATING flag per UEFI 2.7 expectations */
> +	for (i = 0; i < nd_region->ndr_mappings; i++) {
> +		struct nd_mapping *nd_mapping = &nd_region->mapping[i];
> +		struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
> +
> +		/* No need to update region label for non cxl format */
> +		if (!ndd->cxl)
> +			continue;
> +
> +		rc = __pmem_region_label_update(nd_region, nd_mapping, i, 0);
> +

and here.

> +		if (rc)
> +			return rc;
> +	}
> +
> +	return 0;
> +}
> +
>  int __init nd_label_init(void)
>  {
>  	WARN_ON(guid_parse(NVDIMM_BTT_GUID, &nvdimm_btt_guid));
> diff --git a/drivers/nvdimm/label.h b/drivers/nvdimm/label.h
> index 4883b3a1320f..0f428695017d 100644
> --- a/drivers/nvdimm/label.h
> +++ b/drivers/nvdimm/label.h
> @@ -190,6 +190,7 @@ struct nd_namespace_label {
>  struct nd_lsa_label {

Would be better to have this explicitly as a union
unless later patches add more elements.  That way it'll 
be obvious at all sites where it is used that it can be one
of several things.

>  	union {
>  		struct nd_namespace_label ns_label;
> +		struct cxl_region_label rg_label;
>  	};
>  };
>  
> @@ -233,4 +234,5 @@ struct nd_region;
>  struct nd_namespace_pmem;
>  int nd_pmem_namespace_label_update(struct nd_region *nd_region,
>  		struct nd_namespace_pmem *nspm, resource_size_t size);
> +int nd_pmem_region_label_update(struct nd_region *nd_region);
>  #endif /* __LABEL_H__ */