On Wed, 30 Jul 2025 17:41:50 +0530
Neeraj Kumar <s.nee...@samsung.com> 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_CXL_LABEL
> flag for region label. Based on these flags nvdimm driver performs
> operation on namespace label or region label.
>
> NDD_CXL_LABEL will be utilized by cxl driver to enable LSA2.1 region
> label support
>
> Accordingly updated label index version
>
> Signed-off-by: Neeraj Kumar <s.nee...@samsung.com>
Hi Neeraj,
A few comments inline.
> diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
> index 04f4a049599a..7a011ee02d79 100644
> --- a/drivers/nvdimm/label.c
> +++ b/drivers/nvdimm/label.c
> @@ -688,11 +688,25 @@ 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 Spec: 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 Specification 2.7: Label Index Block Definitions */
Odd comment alignment. Either put it on the else so
else /* UEFI 2.7: Label Index Block Defintions */
or indent it an extra tab
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/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
> index e772aae71843..0a55900842c8 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_CXL_LABEL = 9,
This enum is 'curious'. It combined flags from a bunch of different
flags fields and some stuff that are nothing to do with flags.
Anyhow, putting that aside I'd either rename it to something like
NDD_REGION_LABELING (similar to NDD_LABELING that is there for namespace labels
or just have it a meaning it is LSA Format 2.1 and drop the fact htat
also means region labels are supported.
Combination of a comment that talks about one thing and a definition name
that doesn't associate with it seems confusing to me.
Jonathan
> +
> /* need to set a limit somewhere, but yes, this is likely overkill */
> ND_IOCTL_MAX_BUFLEN = SZ_4M,
> ND_CMD_MAX_ELEM = 5,
