[PATCH 7/9] libnvdimm, label: add v1.2 label checksum support

[Dan Williams]

The v1.2 namespace label specification adds a fletcher checksum to each
label instance. Add generation and validation support for the new field.

Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
---
 drivers/nvdimm/label.c |   39 +++++++++++++++++++++++++++++++++++----
 1 file changed, 35 insertions(+), 4 deletions(-)

diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index d7f9916c6ed5..c503362a03c7 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -326,7 +326,8 @@ static bool preamble_next(struct nvdimm_drvdata *ndd,
                        free, nslot);
 }
 
-static bool slot_valid(struct nd_namespace_label *nd_label, u32 slot)
+static bool slot_valid(struct nvdimm_drvdata *ndd,
+               struct nd_namespace_label *nd_label, u32 slot)
 {
        /* check that we are written where we expect to be written */
        if (slot != __le32_to_cpu(nd_label->slot))
@@ -337,6 +338,21 @@ static bool slot_valid(struct nd_namespace_label 
*nd_label, u32 slot)
                                | __le64_to_cpu(nd_label->rawsize)) % SZ_4K)
                return false;
 
+       /* check checksum */
+       if (namespace_label_has(ndd, checksum)) {
+               u64 sum, sum_save;
+
+               sum_save = __le64_to_cpu(nd_label->checksum);
+               nd_label->checksum = __cpu_to_le64(0);
+               sum = nd_fletcher64(nd_label, sizeof_namespace_label(ndd), 1);
+               nd_label->checksum = __cpu_to_le64(sum_save);
+               if (sum != sum_save) {
+                       dev_dbg(ndd->dev, "%s fail checksum. slot: %d expect: 
%#llx\n",
+                               __func__, slot, sum);
+                       return false;
+               }
+       }
+
        return true;
 }
 
@@ -359,7 +375,7 @@ int nd_label_reserve_dpa(struct nvdimm_drvdata *ndd)
 
                nd_label = to_label(ndd, slot);
 
-               if (!slot_valid(nd_label, slot))
+               if (!slot_valid(ndd, nd_label, slot))
                        continue;
 
                memcpy(label_uuid, nd_label->uuid, NSLABEL_UUID_LEN);
@@ -391,7 +407,7 @@ int nd_label_active_count(struct nvdimm_drvdata *ndd)
 
                nd_label = to_label(ndd, slot);
 
-               if (!slot_valid(nd_label, slot)) {
+               if (!slot_valid(ndd, nd_label, slot)) {
                        u32 label_slot = __le32_to_cpu(nd_label->slot);
                        u64 size = __le64_to_cpu(nd_label->rawsize);
                        u64 dpa = __le64_to_cpu(nd_label->dpa);
@@ -419,7 +435,7 @@ struct nd_namespace_label *nd_label_active(struct 
nvdimm_drvdata *ndd, int n)
                struct nd_namespace_label *nd_label;
 
                nd_label = to_label(ndd, slot);
-               if (!slot_valid(nd_label, slot))
+               if (!slot_valid(ndd, nd_label, slot))
                        continue;
 
                if (n-- == 0)
@@ -600,6 +616,13 @@ static int __pmem_label_update(struct nd_region *nd_region,
        nd_label->slot = __cpu_to_le32(slot);
        if (namespace_label_has(ndd, type_guid))
                guid_copy(&nd_label->type_guid, &nd_set->type_guid);
+       if (namespace_label_has(ndd, checksum)) {
+               u64 sum;
+
+               nd_label->checksum = __cpu_to_le64(0);
+               sum = nd_fletcher64(nd_label, sizeof_namespace_label(ndd), 1);
+               nd_label->checksum = __cpu_to_le64(sum);
+       }
        nd_dbg_dpa(nd_region, ndd, res, "%s\n", __func__);
 
        /* update label */
@@ -825,6 +848,14 @@ static int __blk_label_update(struct nd_region *nd_region,
                nd_label->slot = __cpu_to_le32(slot);
                if (namespace_label_has(ndd, type_guid))
                        guid_copy(&nd_label->type_guid, &nd_set->type_guid);
+               if (namespace_label_has(ndd, checksum)) {
+                       u64 sum;
+
+                       nd_label->checksum = __cpu_to_le64(0);
+                       sum = nd_fletcher64(nd_label,
+                                       sizeof_namespace_label(ndd), 1);
+                       nd_label->checksum = __cpu_to_le64(sum);
+               }
 
                /* update label */
                offset = nd_label_offset(ndd, nd_label);