Re: [PATCH V3 01/20] nvdimm/label: Introduce NDD_REGION_LABELING flag to set region label

Dave Jiang
2025-09-19T23:10:42Z

On 9/17/25 6:40 AM, Neeraj Kumar wrote:
> Prior to LSA 2.1 version, LSA contain only namespace labels. LSA 2.1
> introduced in CXL 2.0 Spec, which contain region label along with
> namespace label.
>
> NDD_LABELING flag is used for namespace. Introduced NDD_REGION_LABELING
> flag for region label. Based on these flags nvdimm driver performs
> operation on namespace label or region label.
>
> NDD_REGION_LABELING will be utilized by cxl driver to enable LSA 2.1
> region label support
>
> Accordingly updated label index version
>
> Signed-off-by: Neeraj Kumar <s.neeraj@samsung.com>

With the change noted below,
Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> ---
> drivers/nvdimm/dimm.c | 1 +
> drivers/nvdimm/dimm_devs.c | 7 +++++++
> drivers/nvdimm/label.c | 21 +++++++++++++++++----
> drivers/nvdimm/nd.h | 1 +
> include/linux/libnvdimm.h | 3 +++
> 5 files changed, 29 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
> index 91d9163ee303..bda22cb94e5b 100644
> --- a/drivers/nvdimm/dimm.c
> +++ b/drivers/nvdimm/dimm.c
> @@ -62,6 +62,7 @@ static int nvdimm_probe(struct device *dev)
> if (rc < 0)
> dev_dbg(dev, "failed to unlock dimm: %d\n", rc);
>
> + ndd->cxl = nvdimm_check_region_label_format(ndd->dev);
>
> /*
> * EACCES failures reading the namespace label-area-properties
> diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
> index 21498d461fde..918c3db93195 100644
> --- a/drivers/nvdimm/dimm_devs.c
> +++ b/drivers/nvdimm/dimm_devs.c
> @@ -18,6 +18,13 @@
>
> static DEFINE_IDA(dimm_ida);
>
> +bool nvdimm_check_region_label_format(struct device *dev)

Should be called nvdimm_region_label_supported() since a bool return is expected instead of resolving the checking in the function.

DJ

> +{
> + struct nvdimm *nvdimm = to_nvdimm(dev);
> +
> + return test_bit(NDD_REGION_LABELING, &nvdimm->flags);
> +}
> +
> /*
> * Retrieve bus and dimm handle and return if this bus supports
> * get_config_data commands
> diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
> index 04f4a049599a..0a9b6c5cb2c3 100644
> --- a/drivers/nvdimm/label.c
> +++ b/drivers/nvdimm/label.c
> @@ -688,11 +688,24 @@ static int nd_label_write_index(struct nvdimm_drvdata *ndd, int index, u32 seq,
> - (unsigned long) to_namespace_index(ndd, 0);
> nsindex->labeloff = __cpu_to_le64(offset);
> nsindex->nslot = __cpu_to_le32(nslot);
> - nsindex->major = __cpu_to_le16(1);
> - if (sizeof_namespace_label(ndd) < 256)
> +
> + /* Set LSA Label Index Version */
> + if (ndd->cxl) {
> + /* CXL r3.2: Table 9-9 Label Index Block Layout */
> + nsindex->major = __cpu_to_le16(2);
> nsindex->minor = __cpu_to_le16(1);
> - else
> - nsindex->minor = __cpu_to_le16(2);
> + } else {
> + nsindex->major = __cpu_to_le16(1);
> + /*
> + * NVDIMM Namespace Specification
> + * Table 2: Namespace Label Index Block Fields
> + */
> + if (sizeof_namespace_label(ndd) < 256)
> + nsindex->minor = __cpu_to_le16(1);
> + else /* UEFI 2.7: Label Index Block Definitions */
> + nsindex->minor = __cpu_to_le16(2);
> + }
> +
> nsindex->checksum = __cpu_to_le64(0);
> if (flags & ND_NSINDEX_INIT) {
> unsigned long *free = (unsigned long *) nsindex->free;
> diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
> index cc5c8f3f81e8..158809c2be9e 100644
> --- a/drivers/nvdimm/nd.h
> +++ b/drivers/nvdimm/nd.h
> @@ -522,6 +522,7 @@ void nvdimm_set_labeling(struct device *dev);
> void nvdimm_set_locked(struct device *dev);
> void nvdimm_clear_locked(struct device *dev);
> int nvdimm_security_setup_events(struct device *dev);
> +bool nvdimm_check_region_label_format(struct device *dev);
> #if IS_ENABLED(CONFIG_NVDIMM_KEYS)
> int nvdimm_security_unlock(struct device *dev);
> #else
> diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
> index 28f086c4a187..5696715c33bb 100644
> --- a/include/linux/libnvdimm.h
> +++ b/include/linux/libnvdimm.h
> @@ -44,6 +44,9 @@ enum {
> /* dimm provider wants synchronous registration by __nvdimm_create() */
> NDD_REGISTER_SYNC = 8,
>
> + /* dimm supports region labels (LSA Format 2.1) */
> + NDD_REGION_LABELING = 9,
> +
> /* need to set a limit somewhere, but yes, this is likely overkill */
> ND_IOCTL_MAX_BUFLEN = SZ_4M,
> ND_CMD_MAX_ELEM = 5,