[PATCH 1/3] libnvdimm: Introduce locked DIMM capacity support

From: Dan Williams
Date: Thu Jun 14 2018 - 20:47:24 EST


When a DIMM is locked its namespace label area may not be. Introduce the
distinction of locked namespaces to allow namespace enumeration while
the capacity is locked.

Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/nvdimm/dimm.c | 24 ++++++++++++++++++++++--
drivers/nvdimm/namespace_devs.c | 23 +++++++++++++++++++++++
drivers/nvdimm/nd.h | 1 +
3 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
index 233907889f96..6c8fb7590838 100644
--- a/drivers/nvdimm/dimm.c
+++ b/drivers/nvdimm/dimm.c
@@ -34,6 +34,9 @@ static int nvdimm_probe(struct device *dev)
return rc;
}

+ /* reset locked, to be validated below... */
+ nvdimm_clear_locked(dev);
+
ndd = kzalloc(sizeof(*ndd), GFP_KERNEL);
if (!ndd)
return -ENOMEM;
@@ -48,12 +51,30 @@ static int nvdimm_probe(struct device *dev)
get_device(dev);
kref_init(&ndd->kref);

+ /*
+ * EACCES failures reading the namespace label-area-properties
+ * are interpreted as the DIMM capacity being locked but the
+ * namespace labels themselves being accessible.
+ */
rc = nvdimm_init_nsarea(ndd);
- if (rc == -EACCES)
+ if (rc == -EACCES) {
+ /*
+ * See nvdimm_namespace_common_probe() where we fail to
+ * allow namespaces to probe while the DIMM is locked,
+ * but we do allow for namespace enumeration.
+ */
nvdimm_set_locked(dev);
+ rc = 0;
+ }
if (rc)
goto err;

+ /*
+ * EACCES failures reading the namespace label-data are
+ * interpreted as the label area being locked in addition to the
+ * DIMM capacity. We fail the dimm probe to prevent regions from
+ * attempting to parse the label area.
+ */
rc = nvdimm_init_config_data(ndd);
if (rc == -EACCES)
nvdimm_set_locked(dev);
@@ -72,7 +93,6 @@ static int nvdimm_probe(struct device *dev)
if (rc == 0)
nvdimm_set_aliasing(dev);
}
- nvdimm_clear_locked(dev);
nvdimm_bus_unlock(dev);

if (rc)
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 28afdd668905..cb322f2bc605 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -1144,6 +1144,26 @@ resource_size_t nvdimm_namespace_capacity(struct nd_namespace_common *ndns)
}
EXPORT_SYMBOL(nvdimm_namespace_capacity);

+bool nvdimm_namespace_locked(struct nd_namespace_common *ndns)
+{
+ int i;
+ bool locked = false;
+ struct device *dev = &ndns->dev;
+ struct nd_region *nd_region = to_nd_region(dev->parent);
+
+ for (i = 0; i < nd_region->ndr_mappings; i++) {
+ struct nd_mapping *nd_mapping = &nd_region->mapping[i];
+ struct nvdimm *nvdimm = nd_mapping->nvdimm;
+
+ if (test_bit(NDD_LOCKED, &nvdimm->flags)) {
+ dev_dbg(dev, "%s locked\n", nvdimm_name(nvdimm));
+ locked = true;
+ }
+ }
+ return locked;
+}
+EXPORT_SYMBOL(nvdimm_namespace_locked);
+
static ssize_t size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -1695,6 +1715,9 @@ struct nd_namespace_common *nvdimm_namespace_common_probe(struct device *dev)
}
}

+ if (nvdimm_namespace_locked(ndns))
+ return ERR_PTR(-EACCES);
+
size = nvdimm_namespace_capacity(ndns);
if (size < ND_MIN_NAMESPACE_SIZE) {
dev_dbg(&ndns->dev, "%pa, too small must be at least %#x\n",
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 32e0364b48b9..9d17abd9f8d0 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -357,6 +357,7 @@ struct resource *nvdimm_allocate_dpa(struct nvdimm_drvdata *ndd,
struct nd_label_id *label_id, resource_size_t start,
resource_size_t n);
resource_size_t nvdimm_namespace_capacity(struct nd_namespace_common *ndns);
+bool nvdimm_namespace_locked(struct nd_namespace_common *ndns);
struct nd_namespace_common *nvdimm_namespace_common_probe(struct device *dev);
int nvdimm_namespace_attach_btt(struct nd_namespace_common *ndns);
int nvdimm_namespace_detach_btt(struct nd_btt *nd_btt);