Re: [PATCH V3 07/20] nvdimm/region_label: Add region label delete support

[Dave Jiang <dave.jiang@intel.com>]

On 9/17/25 6:41 AM, Neeraj Kumar wrote:
> Added LSA v2.1 format region label deletion routine. This function is
> used to delete region label from LSA
> 
> Signed-off-by: Neeraj Kumar <s.neeraj@samsung.com>
> ---
>  drivers/nvdimm/label.c          | 79 ++++++++++++++++++++++++++++++---
>  drivers/nvdimm/label.h          |  1 +
>  drivers/nvdimm/namespace_devs.c | 12 +++++
>  drivers/nvdimm/nd.h             |  6 +++
>  include/linux/libnvdimm.h       |  1 +
>  5 files changed, 92 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
> index 209c73f6b7e7..d33db96ba8ba 100644
> --- a/drivers/nvdimm/label.c
> +++ b/drivers/nvdimm/label.c
> @@ -1126,11 +1126,13 @@ static int init_labels(struct nd_mapping *nd_mapping, int num_labels)
>  	return max(num_labels, old_num_labels);
>  }
>  
> -static int del_labels(struct nd_mapping *nd_mapping, uuid_t *uuid)
> +static int del_labels(struct nd_mapping *nd_mapping, uuid_t *uuid,
> +		      enum label_type ltype)
>  {
>  	struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
>  	struct nd_label_ent *label_ent, *e;
>  	struct nd_namespace_index *nsindex;
> +	union nd_lsa_label *nd_label;
>  	unsigned long *free;
>  	LIST_HEAD(list);
>  	u32 nslot, slot;
> @@ -1145,15 +1147,28 @@ static int del_labels(struct nd_mapping *nd_mapping, uuid_t *uuid)
>  
>  	guard(mutex)(&nd_mapping->lock);
>  	list_for_each_entry_safe(label_ent, e, &nd_mapping->labels, list) {
> -		struct nd_namespace_label *nd_label = label_ent->label;
> +		nd_label = (union nd_lsa_label *) label_ent->label;
>  
>  		if (!nd_label)
>  			continue;
>  		active++;
> -		if (!nsl_uuid_equal(ndd, nd_label, uuid))
> -			continue;
> +
> +		switch (ltype) {
> +		case NS_LABEL_TYPE:
> +			if (!nsl_uuid_equal(ndd, &nd_label->ns_label, uuid))
> +				continue;
> +
> +			break;
> +		case RG_LABEL_TYPE:
> +			if (!region_label_uuid_equal(&nd_label->region_label,
> +			    uuid))
> +				continue;
> +
> +			break;
> +		}
> +
>  		active--;
> -		slot = to_slot(ndd, nd_label);
> +		slot = to_slot(ndd, &nd_label->ns_label);
>  		nd_label_free_slot(ndd, slot);
>  		dev_dbg(ndd->dev, "free: %d\n", slot);
>  		list_move_tail(&label_ent->list, &list);
> @@ -1161,7 +1176,7 @@ static int del_labels(struct nd_mapping *nd_mapping, uuid_t *uuid)
>  	}
>  	list_splice_tail_init(&list, &nd_mapping->labels);
>  
> -	if (active == 0) {
> +	if ((ltype == NS_LABEL_TYPE) && (active == 0)) {
>  		nd_mapping_free_labels(nd_mapping);
>  		dev_dbg(ndd->dev, "no more active labels\n");
>  	}
> @@ -1198,7 +1213,8 @@ int nd_pmem_namespace_label_update(struct nd_region *nd_region,
>  		int count = 0;
>  
>  		if (size == 0) {
> -			rc = del_labels(nd_mapping, nspm->uuid);
> +			rc = del_labels(nd_mapping, nspm->uuid,
> +					NS_LABEL_TYPE);
>  			if (rc)
>  				return rc;
>  			continue;
> @@ -1281,6 +1297,55 @@ int nd_pmem_region_label_update(struct nd_region *nd_region)
>  	return 0;
>  }
>  
> +int nd_pmem_region_label_delete(struct nd_region *nd_region)
> +{
> +	struct nd_interleave_set *nd_set = nd_region->nd_set;
> +	struct nd_label_ent *label_ent;
> +	int ns_region_cnt = 0;
> +	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);
> +
> +		/* Find non cxl format supported ndr_mappings */
> +		if (!ndd->cxl) {
> +			dev_info(&nd_region->dev, "Unsupported region label\n");
> +			return -EINVAL;
> +		}
> +
> +		/* Find if any NS label using this region */
> +		guard(mutex)(&nd_mapping->lock);
> +		list_for_each_entry(label_ent, &nd_mapping->labels, list) {
> +			if (!label_ent->label)
> +				continue;
> +
> +			/*
> +			 * Check if any available NS labels has same
> +			 * region_uuid in LSA
> +			 */
> +			if (nsl_region_uuid_equal(label_ent->label,
> +						  &nd_set->uuid))
> +				ns_region_cnt++;

Why not just return -EBUSY here immediately? It seems the code returns -EBUSY as long as there's 1 or more below.

> +		}
> +	}
> +
> +	if (ns_region_cnt) {
> +		dev_dbg(&nd_region->dev, "Region/Namespace label in use\n");
> +		return -EBUSY;
> +	}
> +
> +	for (i = 0; i < nd_region->ndr_mappings; i++) {
> +		struct nd_mapping *nd_mapping = &nd_region->mapping[i];
> +
> +		rc = del_labels(nd_mapping, &nd_set->uuid, RG_LABEL_TYPE);
> +		if (rc)
> +			return rc;
> +	}

Can this be folded into the for loop above or does it a full pass to check before starting the label deletion process?

DJ
> +
> +	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 284e2a763b49..276dd822e142 100644
> --- a/drivers/nvdimm/label.h
> +++ b/drivers/nvdimm/label.h
> @@ -238,4 +238,5 @@ 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);
> +int nd_pmem_region_label_delete(struct nd_region *nd_region);
>  #endif /* __LABEL_H__ */
> diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
> index 559f822ef24f..564a73b1da41 100644
> --- a/drivers/nvdimm/namespace_devs.c
> +++ b/drivers/nvdimm/namespace_devs.c
> @@ -244,6 +244,18 @@ int nd_region_label_update(struct nd_region *nd_region)
>  }
>  EXPORT_SYMBOL_GPL(nd_region_label_update);
>  
> +int nd_region_label_delete(struct nd_region *nd_region)
> +{
> +	int rc;
> +
> +	nvdimm_bus_lock(&nd_region->dev);
> +	rc = nd_pmem_region_label_delete(nd_region);
> +	nvdimm_bus_unlock(&nd_region->dev);
> +
> +	return rc;
> +}
> +EXPORT_SYMBOL_GPL(nd_region_label_delete);
> +
>  static int nd_namespace_label_update(struct nd_region *nd_region,
>  		struct device *dev)
>  {
> diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
> index f04c042dcfa9..046063ea08b6 100644
> --- a/drivers/nvdimm/nd.h
> +++ b/drivers/nvdimm/nd.h
> @@ -331,6 +331,12 @@ static inline bool is_region_label(struct nvdimm_drvdata *ndd,
>  	return uuid_equal(&region_type, ns_type);
>  }
>  
> +static inline bool nsl_region_uuid_equal(struct nd_namespace_label *ns_label,
> +					 const uuid_t *uuid)
> +{
> +	return uuid_equal((uuid_t *) ns_label->cxl.region_uuid, uuid);
> +}
> +
>  static inline bool
>  region_label_uuid_equal(struct cxl_region_label *region_label,
>  			const uuid_t *uuid)
> diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
> index 2c213b9dac66..bbf14a260c93 100644
> --- a/include/linux/libnvdimm.h
> +++ b/include/linux/libnvdimm.h
> @@ -315,6 +315,7 @@ int nvdimm_has_cache(struct nd_region *nd_region);
>  int nvdimm_in_overwrite(struct nvdimm *nvdimm);
>  bool is_nvdimm_sync(struct nd_region *nd_region);
>  int nd_region_label_update(struct nd_region *nd_region);
> +int nd_region_label_delete(struct nd_region *nd_region);
>  
>  static inline int nvdimm_ctl(struct nvdimm *nvdimm, unsigned int cmd, void *buf,
>  		unsigned int buf_len, int *cmd_rc)