label: Prep patch to accommodate cxl lsa 2.1 support

Neeraj Kumar Fri, 05 Sep 2025 00:57:04 -0700

On 18/08/25 02:48PM, Dave Jiang wrote:



On 7/30/25 5:11 AM, Neeraj Kumar wrote:

LSA 2.1 format introduces region label, which can also reside
into LSA along with only namespace label as per v1.1 and v1.2

As both namespace and region labels are of same size of 256 bytes.
Thus renamed "struct nd_namespace_label" to "struct nd_lsa_label",
where both namespace label and region label can stay as union.

No functional change introduced.

Signed-off-by: Neeraj Kumar <[email protected]>
---
 drivers/nvdimm/label.c          | 58 +++++++++++++++++++--------------
 drivers/nvdimm/label.h          | 12 ++++++-
 drivers/nvdimm/namespace_devs.c | 33 +++++++++++++------
 drivers/nvdimm/nd.h             |  2 +-
 4 files changed, 68 insertions(+), 37 deletions(-)

diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index 7a011ee02d79..75bc11da4c11 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -271,7 +271,7 @@ static void nd_label_copy(struct nvdimm_drvdata *ndd,
        memcpy(dst, src, sizeof_namespace_index(ndd));
 }

-static struct nd_namespace_label *nd_label_base(struct nvdimm_drvdata *ndd)
+static struct nd_lsa_label *nd_label_base(struct nvdimm_drvdata *ndd)


This function caught my eye. I think that given the way it's being used, maybe 
it should be returning 'unsigned long' instead of a struct given every instance 
it's being used, it gets converted back to 'unsigned long'.

$ git grep -n nd_label_base
label.c:274:static struct nd_lsa_label *nd_label_base(struct nvdimm_drvdata 
*ndd)
label.c:287:    base = (unsigned long) nd_label_base(ndd);
label.c:296:    base = (unsigned long) nd_label_base(ndd);
label.c:782:    offset = (unsigned long) nd_label_base(ndd)


Yes Dave, Its added long back (4a826c83db4ed). Sure I will fix it in
next patch-set.

 {
        void *base = to_namespace_index(ndd, 0);

@@ -279,7 +279,7 @@ static struct nd_namespace_label *nd_label_base(struct 
nvdimm_drvdata *ndd)
 }

 static int to_slot(struct nvdimm_drvdata *ndd,
-               struct nd_namespace_label *nd_label)
+               struct nd_lsa_label *nd_label)
 {
        unsigned long label, base;

@@ -289,14 +289,14 @@ static int to_slot(struct nvdimm_drvdata *ndd,
        return (label - base) / sizeof_namespace_label(ndd);
 }

-static struct nd_namespace_label *to_label(struct nvdimm_drvdata *ndd, int 
slot)
+static struct nd_lsa_label *to_label(struct nvdimm_drvdata *ndd, int slot)
 {
        unsigned long label, base;

        base = (unsigned long) nd_label_base(ndd);
        label = base + sizeof_namespace_label(ndd) * slot;

-       return (struct nd_namespace_label *) label;
+       return (struct nd_lsa_label *) label;
 }

 #define for_each_clear_bit_le(bit, addr, size) \
@@ -382,9 +382,10 @@ static void nsl_calculate_checksum(struct nvdimm_drvdata 
*ndd,
 }

 static bool slot_valid(struct nvdimm_drvdata *ndd,
-               struct nd_namespace_label *nd_label, u32 slot)
+               struct nd_lsa_label *lsa_label, u32 slot)
 {
        bool valid;
+       struct nd_namespace_label *nd_label = &lsa_label->ns_label;

        /* check that we are written where we expect to be written */
        if (slot != nsl_get_slot(ndd, nd_label))
@@ -405,6 +406,7 @@ int nd_label_reserve_dpa(struct nvdimm_drvdata *ndd)
                return 0; /* no label, nothing to reserve */

        for_each_clear_bit_le(slot, free, nslot) {
+               struct nd_lsa_label *lsa_label;
                struct nd_namespace_label *nd_label;
                struct nd_region *nd_region = NULL;
                struct nd_label_id label_id;
@@ -412,9 +414,10 @@ int nd_label_reserve_dpa(struct nvdimm_drvdata *ndd)
                uuid_t label_uuid;
                u32 flags;

-               nd_label = to_label(ndd, slot);
+               lsa_label = to_label(ndd, slot);
+               nd_label = &lsa_label->ns_label;

-               if (!slot_valid(ndd, nd_label, slot))
+               if (!slot_valid(ndd, lsa_label, slot))
                        continue;

                nsl_get_uuid(ndd, nd_label, &label_uuid);
@@ -565,11 +568,13 @@ int nd_label_active_count(struct nvdimm_drvdata *ndd)
                return 0;

        for_each_clear_bit_le(slot, free, nslot) {
+               struct nd_lsa_label *lsa_label;
                struct nd_namespace_label *nd_label;

-               nd_label = to_label(ndd, slot);
+               lsa_label = to_label(ndd, slot);
+               nd_label = &lsa_label->ns_label;

-               if (!slot_valid(ndd, nd_label, slot)) {
+               if (!slot_valid(ndd, lsa_label, slot)) {
                        u32 label_slot = nsl_get_slot(ndd, nd_label);
                        u64 size = nsl_get_rawsize(ndd, nd_label);
                        u64 dpa = nsl_get_dpa(ndd, nd_label);
@@ -584,7 +589,7 @@ int nd_label_active_count(struct nvdimm_drvdata *ndd)
        return count;
 }

-struct nd_namespace_label *nd_label_active(struct nvdimm_drvdata *ndd, int n)
+struct nd_lsa_label *nd_label_active(struct nvdimm_drvdata *ndd, int n)
 {
        struct nd_namespace_index *nsindex;
        unsigned long *free;
@@ -594,10 +599,10 @@ struct nd_namespace_label *nd_label_active(struct 
nvdimm_drvdata *ndd, int n)
                return NULL;

        for_each_clear_bit_le(slot, free, nslot) {
-               struct nd_namespace_label *nd_label;
+               struct nd_lsa_label *lsa_label;

-               nd_label = to_label(ndd, slot);
-               if (!slot_valid(ndd, nd_label, slot))
+               lsa_label = to_label(ndd, slot);
+               if (!slot_valid(ndd, lsa_label, slot))
                        continue;

                if (n-- == 0)
@@ -738,7 +743,7 @@ static int nd_label_write_index(struct nvdimm_drvdata *ndd, 
int index, u32 seq,
 }

 static unsigned long nd_label_offset(struct nvdimm_drvdata *ndd,
-               struct nd_namespace_label *nd_label)
+               struct nd_lsa_label *nd_label)
 {
        return (unsigned long) nd_label
                - (unsigned long) to_namespace_index(ndd, 0);
@@ -892,6 +897,7 @@ static int __pmem_label_update(struct nd_region *nd_region,
        struct nd_namespace_common *ndns = &nspm->nsio.common;
        struct nd_interleave_set *nd_set = nd_region->nd_set;
        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
+       struct nd_lsa_label *lsa_label;
        struct nd_namespace_label *nd_label;
        struct nd_namespace_index *nsindex;
        struct nd_label_ent *label_ent;
@@ -923,8 +929,10 @@ static int __pmem_label_update(struct nd_region *nd_region,
                return -ENXIO;
        dev_dbg(ndd->dev, "allocated: %d\n", slot);

-       nd_label = to_label(ndd, slot);
-       memset(nd_label, 0, sizeof_namespace_label(ndd));
+       lsa_label = to_label(ndd, slot);
+       memset(lsa_label, 0, sizeof_namespace_label(ndd));
+
+       nd_label = &lsa_label->ns_label;
        nsl_set_uuid(ndd, nd_label, nspm->uuid);
        nsl_set_name(ndd, nd_label, nspm->alt_name);
        nsl_set_flags(ndd, nd_label, flags);
@@ -942,7 +950,7 @@ static int __pmem_label_update(struct nd_region *nd_region,
        nd_dbg_dpa(nd_region, ndd, res, "\n");

        /* update label */
-       offset = nd_label_offset(ndd, nd_label);
+       offset = nd_label_offset(ndd, lsa_label);
        rc = nvdimm_set_config_data(ndd, offset, nd_label,
                        sizeof_namespace_label(ndd));
        if (rc < 0)
@@ -954,7 +962,7 @@ static int __pmem_label_update(struct nd_region *nd_region,
                if (!label_ent->label)
                        continue;
                if (test_and_clear_bit(ND_LABEL_REAP, &label_ent->flags) ||
-                   nsl_uuid_equal(ndd, label_ent->label, nspm->uuid))
+                   nsl_uuid_equal(ndd, &label_ent->label->ns_label, 
nspm->uuid))
                        reap_victim(nd_mapping, label_ent);
        }

@@ -964,14 +972,14 @@ static int __pmem_label_update(struct nd_region 
*nd_region,
        if (rc == 0) {
                list_for_each_entry(label_ent, &nd_mapping->labels, list)
                        if (!label_ent->label) {
-                               label_ent->label = nd_label;
-                               nd_label = NULL;
+                               label_ent->label = lsa_label;
+                               lsa_label = NULL;
                                break;
                        }
-               dev_WARN_ONCE(&nspm->nsio.common.dev, nd_label,
+               dev_WARN_ONCE(&nspm->nsio.common.dev, lsa_label,
                                "failed to track label: %d\n",
-                               to_slot(ndd, nd_label));
-               if (nd_label)
+                               to_slot(ndd, lsa_label));
+               if (lsa_label)
                        rc = -ENXIO;
        }
        mutex_unlock(&nd_mapping->lock);
@@ -1042,12 +1050,12 @@ static int del_labels(struct nd_mapping *nd_mapping, 
uuid_t *uuid)

        mutex_lock(&nd_mapping->lock);
        list_for_each_entry_safe(label_ent, e, &nd_mapping->labels, list) {
-               struct nd_namespace_label *nd_label = label_ent->label;
+               struct nd_lsa_label *nd_label = label_ent->label;

                if (!nd_label)
                        continue;
                active++;
-               if (!nsl_uuid_equal(ndd, nd_label, uuid))
+               if (!nsl_uuid_equal(ndd, &nd_label->ns_label, uuid))
                        continue;
                active--;
                slot = to_slot(ndd, nd_label);
diff --git a/drivers/nvdimm/label.h b/drivers/nvdimm/label.h
index 0650fb4b9821..4883b3a1320f 100644
--- a/drivers/nvdimm/label.h
+++ b/drivers/nvdimm/label.h
@@ -183,6 +183,16 @@ struct nd_namespace_label {
        };
 };

+/*
+ * LSA 2.1 format introduces region label, which can also reside
+ * into LSA along with only namespace label as per v1.1 and v1.2
+ */
+struct nd_lsa_label {
+       union {
+               struct nd_namespace_label ns_label;
+       };
+};
+
 #define NVDIMM_BTT_GUID "8aed63a2-29a2-4c66-8b12-f05d15d3922a"
 #define NVDIMM_BTT2_GUID "18633bfc-1735-4217-8ac9-17239282d3f8"
 #define NVDIMM_PFN_GUID "266400ba-fb9f-4677-bcb0-968f11d0d225"
@@ -215,7 +225,7 @@ struct nvdimm_drvdata;
 int nd_label_data_init(struct nvdimm_drvdata *ndd);
 size_t sizeof_namespace_index(struct nvdimm_drvdata *ndd);
 int nd_label_active_count(struct nvdimm_drvdata *ndd);
-struct nd_namespace_label *nd_label_active(struct nvdimm_drvdata *ndd, int n);
+struct nd_lsa_label *nd_label_active(struct nvdimm_drvdata *ndd, int n);
 u32 nd_label_alloc_slot(struct nvdimm_drvdata *ndd);
 bool nd_label_free_slot(struct nvdimm_drvdata *ndd, u32 slot);
 u32 nd_label_nfree(struct nvdimm_drvdata *ndd);
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 55cfbf1e0a95..bdf1ed6f23d8 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -1009,10 +1009,11 @@ static int namespace_update_uuid(struct nd_region 
*nd_region,

                mutex_lock(&nd_mapping->lock);
                list_for_each_entry(label_ent, &nd_mapping->labels, list) {
-                       struct nd_namespace_label *nd_label = label_ent->label;
+                       struct nd_namespace_label *nd_label;
                        struct nd_label_id label_id;
                        uuid_t uuid;

+                       nd_label = &label_ent->label->ns_label;
                        if (!nd_label)
                                continue;
                        nsl_get_uuid(ndd, nd_label, &uuid);
@@ -1573,11 +1574,14 @@ static bool has_uuid_at_pos(struct nd_region 
*nd_region, const uuid_t *uuid,
                bool found_uuid = false;

                list_for_each_entry(label_ent, &nd_mapping->labels, list) {
-                       struct nd_namespace_label *nd_label = label_ent->label;
+                       struct nd_lsa_label *lsa_label = label_ent->label;
+                       struct nd_namespace_label *nd_label;
                        u16 position;

-                       if (!nd_label)
+                       if (!lsa_label)
                                continue;
+
+                       nd_label = &lsa_label->ns_label;
                        position = nsl_get_position(ndd, nd_label);

                        if (!nsl_validate_isetcookie(ndd, nd_label, cookie))
@@ -1615,17 +1619,21 @@ static int select_pmem_id(struct nd_region *nd_region, 
const uuid_t *pmem_id)
        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);
+               struct nd_lsa_label *lsa_label = NULL;
                struct nd_namespace_label *nd_label = NULL;
                u64 hw_start, hw_end, pmem_start, pmem_end;
                struct nd_label_ent *label_ent;

                lockdep_assert_held(&nd_mapping->lock);
                list_for_each_entry(label_ent, &nd_mapping->labels, list) {
-                       nd_label = label_ent->label;
-                       if (!nd_label)
+                       lsa_label = label_ent->label;
+                       if (!lsa_label)
                                continue;
+
+                       nd_label = &lsa_label->ns_label;
                        if (nsl_uuid_equal(ndd, nd_label, pmem_id))
                                break;
+                       lsa_label = NULL;
                        nd_label = NULL;
                }

@@ -1746,19 +1754,21 @@ static struct device *create_namespace_pmem(struct 
nd_region *nd_region,

        /* Calculate total size and populate namespace properties from label0 */
        for (i = 0; i < nd_region->ndr_mappings; i++) {
+               struct nd_lsa_label *lsa_label;
                struct nd_namespace_label *label0;
                struct nvdimm_drvdata *ndd;

                nd_mapping = &nd_region->mapping[i];
                label_ent = list_first_entry_or_null(&nd_mapping->labels,
                                typeof(*label_ent), list);
-               label0 = label_ent ? label_ent->label : NULL;
+               lsa_label = label_ent ? label_ent->label : NULL;

-               if (!label0) {
+               if (!lsa_label) {
                        WARN_ON(1);
                        continue;
                }

+               label0 = &lsa_label->ns_label;
                ndd = to_ndd(nd_mapping);
                size += nsl_get_rawsize(ndd, label0);
                if (nsl_get_position(ndd, label0) != 0)
@@ -1943,12 +1953,15 @@ static struct device **scan_labels(struct nd_region 
*nd_region)

        /* "safe" because create_namespace_pmem() might list_move() label_ent */
        list_for_each_entry_safe(label_ent, e, &nd_mapping->labels, list) {
-               struct nd_namespace_label *nd_label = label_ent->label;
+               struct nd_lsa_label *lsa_label = label_ent->label;
+               struct nd_namespace_label *nd_label;
                struct device **__devs;

-               if (!nd_label)
+               if (!lsa_label)
                        continue;

+               nd_label = &lsa_label->ns_label;
+
                /* skip labels that describe extents outside of the region */
                if (nsl_get_dpa(ndd, nd_label) < nd_mapping->start ||
                    nsl_get_dpa(ndd, nd_label) > map_end)
@@ -2122,7 +2135,7 @@ static int init_active_labels(struct nd_region *nd_region)
                if (!count)
                        continue;
                for (j = 0; j < count; j++) {
-                       struct nd_namespace_label *label;
+                       struct nd_lsa_label *label;

                        label_ent = kzalloc(sizeof(*label_ent), GFP_KERNEL);
                        if (!label_ent)
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 1cc06cc58d14..61348dee687d 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -376,7 +376,7 @@ enum nd_label_flags {
 struct nd_label_ent {
        struct list_head list;
        unsigned long flags;
-       struct nd_namespace_label *label;
+       struct nd_lsa_label *label;


Looking at the series a bit more, I don't think creating 'struct nd_lsa_label' 
and making all the changes in this patch is necessary. I think an unamed union 
here of 'struct nd_namespace_label' and 'struct cxl_region_label' should be 
fine. Most of the CXL region handling should be quite different than namespace 
handling that the code paths will diverge. Adding a few helper functions should 
address some of the common code paths or creating separate cxl region based 
helpers to deal with the rest. i.e. slot_valid() can take a slot number rather 
than a label type. Being intentional in handling sepcific labeling may be 
better than trying to force a union between region and namespace labeling.

};


Thanks for your suggestion Dave. Yes using unnamed union here will be
helpful. I will fix the change in next patch-set.


Regards,
Neeraj

Re: [PATCH V2 02/20] nvdimm/label: Prep patch to accommodate cxl lsa 2.1 support

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