libnvdimm, label: convert label tracking to a linked list

In preparation for enabling multiple namespaces per pmem region, convert
the label tracking to use a linked list.  In particular this will allow
select_pmem_id() to move labels from the unvalidated state to the
validated state.  Currently we only track one validated set per-region.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

5 files changed, 225 insertions, 120 deletions

diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index 96526dcfdd37..c37357210428 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -499,6 +499,7 @@ static int __pmem_label_update(struct nd_region *nd_region,
         struct nd_namespace_label *victim_label;
         struct nd_namespace_label *nd_label;
         struct nd_namespace_index *nsindex;
+        struct nd_label_ent *label_ent;
         unsigned long *free;
         u32 nslot, slot;
         size_t offset;
@@ -536,8 +537,13 @@ static int __pmem_label_update(struct nd_region *nd_region,
                 return rc;
 
         /* Garbage collect the previous label */
-        victim_label = nd_mapping->labels[0];
+        mutex_lock(&nd_mapping->lock);
+        label_ent = list_first_entry_or_null(&nd_mapping->labels,
+                        typeof(*label_ent), list);
+        WARN_ON(!label_ent);
+        victim_label = label_ent ? label_ent->label : NULL;
         if (victim_label) {
+                label_ent->label = NULL;
                 slot = to_slot(ndd, victim_label);
                 nd_label_free_slot(ndd, slot);
                 dev_dbg(ndd->dev, "%s: free: %d\n", __func__, slot);
@@ -546,28 +552,11 @@ static int __pmem_label_update(struct nd_region *nd_region,
         /* update index */
         rc = nd_label_write_index(ndd, ndd->ns_next,
                         nd_inc_seq(__le32_to_cpu(nsindex->seq)), 0);
-        if (rc < 0)
-                return rc;
-
-        nd_mapping->labels[0] = nd_label;
-
-        return 0;
-}
-
-static void del_label(struct nd_mapping *nd_mapping, int l)
-{
-        struct nd_namespace_label *next_label, *nd_label;
-        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
-        unsigned int slot;
-        int j;
+        if (rc == 0 && label_ent)
+                label_ent->label = nd_label;
+        mutex_unlock(&nd_mapping->lock);
 
-        nd_label = nd_mapping->labels[l];
-        slot = to_slot(ndd, nd_label);
-        dev_vdbg(ndd->dev, "%s: clear: %d\n", __func__, slot);
-
-        for (j = l; (next_label = nd_mapping->labels[j + 1]); j++)
-                nd_mapping->labels[j] = next_label;
-        nd_mapping->labels[j] = NULL;
+        return rc;
 }
 
 static bool is_old_resource(struct resource *res, struct resource **list, int n)
@@ -607,14 +596,16 @@ static int __blk_label_update(struct nd_region *nd_region,
                 struct nd_mapping *nd_mapping, struct nd_namespace_blk *nsblk,
                 int num_labels)
 {
-        int i, l, alloc, victims, nfree, old_num_resources, nlabel, rc = -ENXIO;
+        int i, alloc, victims, nfree, old_num_resources, nlabel, rc = -ENXIO;
         struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
         struct nd_namespace_label *nd_label;
+        struct nd_label_ent *label_ent, *e;
         struct nd_namespace_index *nsindex;
         unsigned long *free, *victim_map = NULL;
         struct resource *res, **old_res_list;
         struct nd_label_id label_id;
         u8 uuid[NSLABEL_UUID_LEN];
+        LIST_HEAD(list);
         u32 nslot, slot;
 
         if (!preamble_next(ndd, &nsindex, &free, &nslot))
@@ -736,15 +727,22 @@ static int __blk_label_update(struct nd_region *nd_region,
          * entries in nd_mapping->labels
          */
         nlabel = 0;
-        for_each_label(l, nd_label, nd_mapping->labels) {
+        mutex_lock(&nd_mapping->lock);
+        list_for_each_entry_safe(label_ent, e, &nd_mapping->labels, list) {
+                nd_label = label_ent->label;
+                if (!nd_label)
+                        continue;
                 nlabel++;
                 memcpy(uuid, nd_label->uuid, NSLABEL_UUID_LEN);
                 if (memcmp(uuid, nsblk->uuid, NSLABEL_UUID_LEN) != 0)
                         continue;
                 nlabel--;
-                del_label(nd_mapping, l);
-                l--; /* retry with the new label at this index */
+                list_move(&label_ent->list, &list);
+                label_ent->label = NULL;
         }
+        list_splice_tail_init(&list, &nd_mapping->labels);
+        mutex_unlock(&nd_mapping->lock);
+
         if (nlabel + nsblk->num_resources > num_labels) {
                 /*
                  * Bug, we can't end up with more resources than
@@ -755,6 +753,15 @@ static int __blk_label_update(struct nd_region *nd_region,
                 goto out;
         }
 
+        mutex_lock(&nd_mapping->lock);
+        label_ent = list_first_entry_or_null(&nd_mapping->labels,
+                        typeof(*label_ent), list);
+        if (!label_ent) {
+                WARN_ON(1);
+                mutex_unlock(&nd_mapping->lock);
+                rc = -ENXIO;
+                goto out;
+        }
         for_each_clear_bit_le(slot, free, nslot) {
                 nd_label = nd_label_base(ndd) + slot;
                 memcpy(uuid, nd_label->uuid, NSLABEL_UUID_LEN);
@@ -762,11 +769,19 @@ static int __blk_label_update(struct nd_region *nd_region,
                         continue;
                 res = to_resource(ndd, nd_label);
                 res->flags &= ~DPA_RESOURCE_ADJUSTED;
-                dev_vdbg(&nsblk->common.dev, "assign label[%d] slot: %d\n",
-                                l, slot);
-                nd_mapping->labels[l++] = nd_label;
+                dev_vdbg(&nsblk->common.dev, "assign label slot: %d\n", slot);
+                list_for_each_entry_from(label_ent, &nd_mapping->labels, list) {
+                        if (label_ent->label)
+                                continue;
+                        label_ent->label = nd_label;
+                        nd_label = NULL;
+                        break;
+                }
+                if (nd_label)
+                        dev_WARN(&nsblk->common.dev,
+                                        "failed to track label slot%d\n", slot);
         }
-        nd_mapping->labels[l] = NULL;
+        mutex_unlock(&nd_mapping->lock);
 
  out:
         kfree(old_res_list);
@@ -788,32 +803,28 @@ static int __blk_label_update(struct nd_region *nd_region,
 
 static int init_labels(struct nd_mapping *nd_mapping, int num_labels)
 {
-        int i, l, old_num_labels = 0;
+        int i, old_num_labels = 0;
+        struct nd_label_ent *label_ent;
         struct nd_namespace_index *nsindex;
-        struct nd_namespace_label *nd_label;
         struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
-        size_t size = (num_labels + 1) * sizeof(struct nd_namespace_label *);
 
-        for_each_label(l, nd_label, nd_mapping->labels)
+        mutex_lock(&nd_mapping->lock);
+        list_for_each_entry(label_ent, &nd_mapping->labels, list)
                 old_num_labels++;
+        mutex_unlock(&nd_mapping->lock);
 
         /*
          * We need to preserve all the old labels for the mapping so
          * they can be garbage collected after writing the new labels.
          */
-        if (num_labels > old_num_labels) {
-                struct nd_namespace_label **labels;
-
-                labels = krealloc(nd_mapping->labels, size, GFP_KERNEL);
-                if (!labels)
+        for (i = old_num_labels; i < num_labels; i++) {
+                label_ent = kzalloc(sizeof(*label_ent), GFP_KERNEL);
+                if (!label_ent)
                         return -ENOMEM;
-                nd_mapping->labels = labels;
+                mutex_lock(&nd_mapping->lock);
+                list_add_tail(&label_ent->list, &nd_mapping->labels);
+                mutex_unlock(&nd_mapping->lock);
         }
-        if (!nd_mapping->labels)
-                return -ENOMEM;
-
-        for (i = old_num_labels; i <= num_labels; i++)
-                nd_mapping->labels[i] = NULL;
 
         if (ndd->ns_current == -1 || ndd->ns_next == -1)
                 /* pass */;
@@ -837,42 +848,45 @@ static int init_labels(struct nd_mapping *nd_mapping, int num_labels)
 static int del_labels(struct nd_mapping *nd_mapping, u8 *uuid)
 {
         struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
-        struct nd_namespace_label *nd_label;
+        struct nd_label_ent *label_ent, *e;
         struct nd_namespace_index *nsindex;
         u8 label_uuid[NSLABEL_UUID_LEN];
-        int l, num_freed = 0;
         unsigned long *free;
+        LIST_HEAD(list);
         u32 nslot, slot;
+        int active = 0;
 
         if (!uuid)
                 return 0;
 
         /* no index || no labels == nothing to delete */
-        if (!preamble_next(ndd, &nsindex, &free, &nslot)
-                        || !nd_mapping->labels)
+        if (!preamble_next(ndd, &nsindex, &free, &nslot))
                 return 0;
 
-        for_each_label(l, nd_label, nd_mapping->labels) {
+        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;
+
+                if (!nd_label)
+                        continue;
+                active++;
                 memcpy(label_uuid, nd_label->uuid, NSLABEL_UUID_LEN);
                 if (memcmp(label_uuid, uuid, NSLABEL_UUID_LEN) != 0)
                         continue;
+                active--;
                 slot = to_slot(ndd, nd_label);
                 nd_label_free_slot(ndd, slot);
                 dev_dbg(ndd->dev, "%s: free: %d\n", __func__, slot);
-                del_label(nd_mapping, l);
-                num_freed++;
-                l--; /* retry with new label at this index */
+                list_move_tail(&label_ent->list, &list);
+                label_ent->label = NULL;
         }
+        list_splice_tail_init(&list, &nd_mapping->labels);
 
-        if (num_freed > l) {
-                /*
-                 * num_freed will only ever be > l when we delete the last
-                 * label
-                 */
-                kfree(nd_mapping->labels);
-                nd_mapping->labels = NULL;
-                dev_dbg(ndd->dev, "%s: no more labels\n", __func__);
+        if (active == 0) {
+                nd_mapping_free_labels(nd_mapping);
+                dev_dbg(ndd->dev, "%s: no more active labels\n", __func__);
         }
+        mutex_unlock(&nd_mapping->lock);
 
         return nd_label_write_index(ndd, ndd->ns_next,
                         nd_inc_seq(__le32_to_cpu(nsindex->seq)), 0);
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 4f0a21308417..9f4188c78120 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -14,6 +14,7 @@
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/pmem.h>
+#include <linux/list.h>
 #include <linux/nd.h>
 #include "nd-core.h"
 #include "nd.h"
@@ -1089,7 +1090,7 @@ static int namespace_update_uuid(struct nd_region *nd_region,
                  *
                  * FIXME: can we delete uuid with zero dpa allocated?
                  */
-                if (nd_mapping->labels)
+                if (list_empty(&nd_mapping->labels))
                         return -EBUSY;
         }
 
@@ -1491,14 +1492,19 @@ static bool has_uuid_at_pos(struct nd_region *nd_region, u8 *uuid,
 
         for (i = 0; i < nd_region->ndr_mappings; i++) {
                 struct nd_mapping *nd_mapping = &nd_region->mapping[i];
-                struct nd_namespace_label *nd_label;
+                struct nd_label_ent *label_ent;
                 bool found_uuid = false;
-                int l;
 
-                for_each_label(l, nd_label, nd_mapping->labels) {
-                        u64 isetcookie = __le64_to_cpu(nd_label->isetcookie);
-                        u16 position = __le16_to_cpu(nd_label->position);
-                        u16 nlabel = __le16_to_cpu(nd_label->nlabel);
+                list_for_each_entry(label_ent, &nd_mapping->labels, list) {
+                        struct nd_namespace_label *nd_label = label_ent->label;
+                        u16 position, nlabel;
+                        u64 isetcookie;
+
+                        if (!nd_label)
+                                continue;
+                        isetcookie = __le64_to_cpu(nd_label->isetcookie);
+                        position = __le16_to_cpu(nd_label->position);
+                        nlabel = __le16_to_cpu(nd_label->nlabel);
 
                         if (isetcookie != cookie)
                                 continue;
@@ -1528,7 +1534,6 @@ static bool has_uuid_at_pos(struct nd_region *nd_region, u8 *uuid,
 
 static int select_pmem_id(struct nd_region *nd_region, u8 *pmem_id)
 {
-        struct nd_namespace_label *select = NULL;
         int i;
 
         if (!pmem_id)
@@ -1536,35 +1541,47 @@ static int select_pmem_id(struct nd_region *nd_region, u8 *pmem_id)
 
         for (i = 0; i < nd_region->ndr_mappings; i++) {
                 struct nd_mapping *nd_mapping = &nd_region->mapping[i];
-                struct nd_namespace_label *nd_label;
+                struct nd_namespace_label *nd_label = NULL;
                 u64 hw_start, hw_end, pmem_start, pmem_end;
-                int l;
+                struct nd_label_ent *label_ent;
 
-                for_each_label(l, nd_label, nd_mapping->labels)
+                mutex_lock(&nd_mapping->lock);
+                list_for_each_entry(label_ent, &nd_mapping->labels, list) {
+                        nd_label = label_ent->label;
+                        if (!nd_label)
+                                continue;
                         if (memcmp(nd_label->uuid, pmem_id, NSLABEL_UUID_LEN) == 0)
                                 break;
+                        nd_label = NULL;
+                }
+                mutex_unlock(&nd_mapping->lock);
 
                 if (!nd_label) {
                         WARN_ON(1);
                         return -EINVAL;
                 }
 
-                select = nd_label;
                 /*
                  * Check that this label is compliant with the dpa
                  * range published in NFIT
                  */
                 hw_start = nd_mapping->start;
                 hw_end = hw_start + nd_mapping->size;
-                pmem_start = __le64_to_cpu(select->dpa);
-                pmem_end = pmem_start + __le64_to_cpu(select->rawsize);
+                pmem_start = __le64_to_cpu(nd_label->dpa);
+                pmem_end = pmem_start + __le64_to_cpu(nd_label->rawsize);
                 if (pmem_start == hw_start && pmem_end <= hw_end)
                         /* pass */;
                 else
                         return -EINVAL;
 
-                nd_mapping->labels[0] = select;
-                nd_mapping->labels[1] = NULL;
+                mutex_lock(&nd_mapping->lock);
+                label_ent = list_first_entry(&nd_mapping->labels,
+                                typeof(*label_ent), list);
+                label_ent->label = nd_label;
+                list_del(&label_ent->list);
+                nd_mapping_free_labels(nd_mapping);
+                list_add(&label_ent->list, &nd_mapping->labels);
+                mutex_unlock(&nd_mapping->lock);
         }
         return 0;
 }
@@ -1577,11 +1594,12 @@ static int find_pmem_label_set(struct nd_region *nd_region,
                 struct nd_namespace_pmem *nspm)
 {
         u64 cookie = nd_region_interleave_set_cookie(nd_region);
-        struct nd_namespace_label *nd_label;
         u8 select_id[NSLABEL_UUID_LEN];
+        struct nd_label_ent *label_ent;
+        struct nd_mapping *nd_mapping;
         resource_size_t size = 0;
         u8 *pmem_id = NULL;
-        int rc = -ENODEV, l;
+        int rc = 0;
         u16 i;
 
         if (cookie == 0) {
@@ -1593,13 +1611,19 @@ static int find_pmem_label_set(struct nd_region *nd_region,
          * Find a complete set of labels by uuid.  By definition we can start
          * with any mapping as the reference label
          */
-        for_each_label(l, nd_label, nd_region->mapping[0].labels) {
-                u64 isetcookie = __le64_to_cpu(nd_label->isetcookie);
+        for (i = 0; i < nd_region->ndr_mappings; i++) {
+                nd_mapping = &nd_region->mapping[i];
+                mutex_lock_nested(&nd_mapping->lock, i);
+        }
+        list_for_each_entry(label_ent, &nd_region->mapping[0].labels, list) {
+                struct nd_namespace_label *nd_label = label_ent->label;
 
-                if (isetcookie != cookie)
+                if (!nd_label)
+                        continue;
+                if (__le64_to_cpu(nd_label->isetcookie) != cookie)
                         continue;
 
-                for (i = 0; nd_region->ndr_mappings; i++)
+                for (i = 0; i < nd_region->ndr_mappings; i++)
                         if (!has_uuid_at_pos(nd_region, nd_label->uuid,
                                                 cookie, i))
                                 break;
@@ -1611,18 +1635,27 @@ static int find_pmem_label_set(struct nd_region *nd_region,
                          * dimm with two instances of the same uuid.
                          */
                         rc = -EINVAL;
-                        goto err;
+                        break;
                 } else if (pmem_id) {
                         /*
                          * If there is more than one valid uuid set, we
                          * need userspace to clean this up.
                          */
                         rc = -EBUSY;
-                        goto err;
+                        break;
                 }
                 memcpy(select_id, nd_label->uuid, NSLABEL_UUID_LEN);
                 pmem_id = select_id;
         }
+        for (i = 0; i < nd_region->ndr_mappings; i++) {
+                int reverse = nd_region->ndr_mappings - 1 - i;
+
+                nd_mapping = &nd_region->mapping[reverse];
+                mutex_unlock(&nd_mapping->lock);
+        }
+
+        if (rc)
+                goto err;
 
         /*
          * Fix up each mapping's 'labels' to have the validated pmem label for
@@ -1638,8 +1671,19 @@ static int find_pmem_label_set(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_mapping *nd_mapping = &nd_region->mapping[i];
-                struct nd_namespace_label *label0 = nd_mapping->labels[0];
+                struct nd_namespace_label *label0;
+
+                nd_mapping = &nd_region->mapping[i];
+                mutex_lock(&nd_mapping->lock);
+                label_ent = list_first_entry_or_null(&nd_mapping->labels,
+                                typeof(*label_ent), list);
+                label0 = label_ent ? label_ent->label : 0;
+                mutex_unlock(&nd_mapping->lock);
+
+                if (!label0) {
+                        WARN_ON(1);
+                        continue;
+                }
 
                 size += __le64_to_cpu(label0->rawsize);
                 if (__le16_to_cpu(label0->position) != 0)
@@ -1700,8 +1744,9 @@ static struct device **create_namespace_pmem(struct nd_region *nd_region)
                 for (i = 0; i < nd_region->ndr_mappings; i++) {
                         struct nd_mapping *nd_mapping = &nd_region->mapping[i];
 
-                        kfree(nd_mapping->labels);
-                        nd_mapping->labels = NULL;
+                        mutex_lock(&nd_mapping->lock);
+                        nd_mapping_free_labels(nd_mapping);
+                        mutex_unlock(&nd_mapping->lock);
                 }
 
                 /* Publish a zero-sized namespace for userspace to configure. */
@@ -1822,25 +1867,25 @@ void nd_region_create_btt_seed(struct nd_region *nd_region)
                 dev_err(&nd_region->dev, "failed to create btt namespace\n");
 }
 
-static struct device **create_namespace_blk(struct nd_region *nd_region)
+static struct device **scan_labels(struct nd_region *nd_region,
+                struct nd_mapping *nd_mapping)
 {
-        struct nd_mapping *nd_mapping = &nd_region->mapping[0];
-        struct nd_namespace_label *nd_label;
+        struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
         struct device *dev, **devs = NULL;
         struct nd_namespace_blk *nsblk;
-        struct nvdimm_drvdata *ndd;
-        int i, l, count = 0;
-        struct resource *res;
-
-        if (nd_region->ndr_mappings == 0)
-                return NULL;
+        struct nd_label_ent *label_ent;
+        int i, count = 0;
 
-        ndd = to_ndd(nd_mapping);
-        for_each_label(l, nd_label, nd_mapping->labels) {
-                u32 flags = __le32_to_cpu(nd_label->flags);
+        list_for_each_entry(label_ent, &nd_mapping->labels, list) {
+                struct nd_namespace_label *nd_label = label_ent->label;
                 char *name[NSLABEL_NAME_LEN];
                 struct device **__devs;
+                struct resource *res;
+                u32 flags;
 
+                if (!nd_label)
+                        continue;
+                flags = __le32_to_cpu(nd_label->flags);
                 if (flags & NSLABEL_FLAG_LOCAL)
                         /* pass */;
                 else
@@ -1899,12 +1944,7 @@ static struct device **create_namespace_blk(struct nd_region *nd_region)
 
         if (count == 0) {
                 /* Publish a zero-sized namespace for userspace to configure. */
-                for (i = 0; i < nd_region->ndr_mappings; i++) {
-                        struct nd_mapping *nd_mapping = &nd_region->mapping[i];
-
-                        kfree(nd_mapping->labels);
-                        nd_mapping->labels = NULL;
-                }
+                nd_mapping_free_labels(nd_mapping);
 
                 devs = kcalloc(2, sizeof(dev), GFP_KERNEL);
                 if (!devs)
@@ -1920,8 +1960,8 @@ static struct device **create_namespace_blk(struct nd_region *nd_region)
 
         return devs;
 
-err:
-        for (i = 0; i < count; i++) {
+ err:
+        for (i = 0; devs[i]; i++) {
                 nsblk = to_nd_namespace_blk(devs[i]);
                 namespace_blk_release(&nsblk->common.dev);
         }
@@ -1929,6 +1969,21 @@ err:
         return NULL;
 }
 
+static struct device **create_namespace_blk(struct nd_region *nd_region)
+{
+        struct nd_mapping *nd_mapping = &nd_region->mapping[0];
+        struct device **devs;
+
+        if (nd_region->ndr_mappings == 0)
+                return NULL;
+
+        mutex_lock(&nd_mapping->lock);
+        devs = scan_labels(nd_region, nd_mapping);
+        mutex_unlock(&nd_mapping->lock);
+
+        return devs;
+}
+
 static int init_active_labels(struct nd_region *nd_region)
 {
         int i;
@@ -1937,6 +1992,7 @@ static int init_active_labels(struct nd_region *nd_region)
                 struct nd_mapping *nd_mapping = &nd_region->mapping[i];
                 struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
                 struct nvdimm *nvdimm = nd_mapping->nvdimm;
+                struct nd_label_ent *label_ent;
                 int count, j;
 
                 /*
@@ -1958,16 +2014,27 @@ static int init_active_labels(struct nd_region *nd_region)
                 dev_dbg(ndd->dev, "%s: %d\n", __func__, count);
                 if (!count)
                         continue;
-                nd_mapping->labels = kcalloc(count + 1, sizeof(void *),
-                                GFP_KERNEL);
-                if (!nd_mapping->labels)
-                        return -ENOMEM;
                 for (j = 0; j < count; j++) {
                         struct nd_namespace_label *label;
 
+                        label_ent = kzalloc(sizeof(*label_ent), GFP_KERNEL);
+                        if (!label_ent)
+                                break;
                         label = nd_label_active(ndd, j);
-                        nd_mapping->labels[j] = label;
+                        label_ent->label = label;
+
+                        mutex_lock(&nd_mapping->lock);
+                        list_add_tail(&label_ent->list, &nd_mapping->labels);
+                        mutex_unlock(&nd_mapping->lock);
                 }
+
+                if (j >= count)
+                        continue;
+
+                mutex_lock(&nd_mapping->lock);
+                nd_mapping_free_labels(nd_mapping);
+                mutex_unlock(&nd_mapping->lock);
+                return -ENOMEM;
         }
 
         return 0;
diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index 1414784c6c2b..fb3ade0d4a83 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -73,6 +73,7 @@ bool nd_is_uuid_unique(struct device *dev, u8 *uuid);
 struct nd_region;
 struct nvdimm_drvdata;
 struct nd_mapping;
+void nd_mapping_free_labels(struct nd_mapping *nd_mapping);
 resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
                 struct nd_mapping *nd_mapping, resource_size_t *overlap);
 resource_size_t nd_blk_available_dpa(struct nd_mapping *nd_mapping);
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index e58c40824e1f..f67c61f1a8a4 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -83,9 +83,6 @@ static inline struct nd_namespace_index *to_next_namespace_index(
                 (unsigned long long) (res ? resource_size(res) : 0), \
                 (unsigned long long) (res ? res->start : 0), ##arg)
 
-#define for_each_label(l, label, labels) \
-        for (l = 0; (label = labels ? labels[l] : NULL); l++)
-
 #define for_each_dpa_resource(ndd, res) \
         for (res = (ndd)->dpa.child; res; res = res->sibling)
 
@@ -98,11 +95,22 @@ struct nd_percpu_lane {
         spinlock_t lock;
 };
 
+struct nd_label_ent {
+        struct list_head list;
+        struct nd_namespace_label *label;
+};
+
+enum nd_mapping_lock_class {
+        ND_MAPPING_CLASS0,
+        ND_MAPPING_UUID_SCAN,
+};
+
 struct nd_mapping {
         struct nvdimm *nvdimm;
-        struct nd_namespace_label **labels;
         u64 start;
         u64 size;
+        struct list_head labels;
+        struct mutex lock;
         /*
          * @ndd is for private use at region enable / disable time for
          * get_ndd() + put_ndd(), all other nd_mapping to ndd
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 0ff43cbb15e3..19bcd68c4141 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -487,6 +487,17 @@ u64 nd_region_interleave_set_cookie(struct nd_region *nd_region)
         return 0;
 }
 
+void nd_mapping_free_labels(struct nd_mapping *nd_mapping)
+{
+        struct nd_label_ent *label_ent, *e;
+
+        WARN_ON(!mutex_is_locked(&nd_mapping->lock));
+        list_for_each_entry_safe(label_ent, e, &nd_mapping->labels, list) {
+                list_del(&label_ent->list);
+                kfree(label_ent);
+        }
+}
+
 /*
  * Upon successful probe/remove, take/release a reference on the
  * associated interleave set (if present), and plant new btt + namespace
@@ -507,8 +518,10 @@ static void nd_region_notify_driver_action(struct nvdimm_bus *nvdimm_bus,
                         struct nvdimm_drvdata *ndd = nd_mapping->ndd;
                         struct nvdimm *nvdimm = nd_mapping->nvdimm;
 
-                        kfree(nd_mapping->labels);
-                        nd_mapping->labels = NULL;
+                        mutex_lock(&nd_mapping->lock);
+                        nd_mapping_free_labels(nd_mapping);
+                        mutex_unlock(&nd_mapping->lock);
+
                         put_ndd(ndd);
                         nd_mapping->ndd = NULL;
                         if (ndd)
@@ -816,6 +829,8 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
                 nd_region->mapping[i].nvdimm = nvdimm;
                 nd_region->mapping[i].start = mapping->start;
                 nd_region->mapping[i].size = mapping->size;
+                INIT_LIST_HEAD(&nd_region->mapping[i].labels);
+                mutex_init(&nd_region->mapping[i].lock);
 
                 get_device(&nvdimm->dev);
         }