On 8/13/25 6:12 AM, Jonathan Cameron wrote:
> 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.
I agree. I had a conversation with Dan about it where I mentioned calling it
CXL to describe LSA 2.1 just doesn't seem quite right. He also offered up
something like NDD_REGION_LABELING instead of NDD_CXL_LABEL. So +1 to this
comment.
DJ
>
> 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,
>
>
