On Tue, 17 Jun 2025 18:09:25 +0530
Neeraj Kumar <s.nee...@samsung.com> wrote:
> NDD_CXL_LABEL is introduced to set cxl LSA 2.1 label format
> Accordingly updated label index version
>
> Signed-off-by: Neeraj Kumar <s.nee...@samsung.com>
A few local comments. I'll need to read on to figure out how this
fits in generally.
> ---
> drivers/nvdimm/dimm.c | 1 +
> drivers/nvdimm/dimm_devs.c | 10 ++++++++++
> drivers/nvdimm/label.c | 16 ++++++++++++----
> drivers/nvdimm/nd.h | 1 +
> include/linux/libnvdimm.h | 3 +++
> 5 files changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
> index 91d9163ee303..8753b5cd91cc 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_cxl_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..e8f545f889fd 100644
> --- a/drivers/nvdimm/dimm_devs.c
> +++ b/drivers/nvdimm/dimm_devs.c
> @@ -18,6 +18,16 @@
>
> static DEFINE_IDA(dimm_ida);
>
> +bool nvdimm_check_cxl_label_format(struct device *dev)
> +{
> + struct nvdimm *nvdimm = to_nvdimm(dev);
> +
> + if (test_bit(NDD_CXL_LABEL, &nvdimm->flags))
> + return true;
> +
> + return false;
return test_bit(NDD_CXL_LABEL, &nvdimm->flags);
Unless this is going to get more complex in later patches, in which case
may be fine to ignore this comment.
> +}
> +
> /*
> * 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 082253a3a956..48b5ba90216d 100644
> --- a/drivers/nvdimm/label.c
> +++ b/drivers/nvdimm/label.c
> @@ -687,11 +687,19 @@ 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)
> +
> + /* Support CXL LSA 2.1 label format */
Might be good to sprinkle some extra details in the references.
E.g. CXL r3.2 Table 9-9 Label Index Block Layout
> + if (ndd->cxl) {
> + 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);
Same for these. Case of making reviewers jobs easier by
giving them breadcrumb trails to follow.
> + if (sizeof_namespace_label(ndd) < 256)
> + nsindex->minor = __cpu_to_le16(1);
> + else
> + 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 5ca06e9a2d29..304f0e9904f1 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_cxl_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 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,
> +
> /* need to set a limit somewhere, but yes, this is likely overkill */
> ND_IOCTL_MAX_BUFLEN = SZ_4M,
> ND_CMD_MAX_ELEM = 5,
