libnvdimm: Simplify root read-only definition for the 'resource' attribute

Rather than update the permission in ->is_visible() set the permission
directly at declaration time.

Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Link: https://lore.kernel.org/r/157309905534.1582359.13927459228885931097.stgit@dwillia2-desk3.amr.corp.intel.com

drivers/nvdimm/namespace_devs.c

@@ -1303,7 +1303,7 @@ static ssize_t resource_show(struct device *dev,
 		return -ENXIO;
 	return sprintf(buf, "%#llx\n", (unsigned long long) res->start);
 }
-static DEVICE_ATTR_RO(resource);
+static DEVICE_ATTR(resource, 0400, resource_show, NULL);
 
 static const unsigned long blk_lbasize_supported[] = { 512, 520, 528,
 	4096, 4104, 4160, 4224, 0 };
@@ -1619,11 +1619,8 @@ static umode_t namespace_visible(struct kobject *kobj,
 {
 	struct device *dev = container_of(kobj, struct device, kobj);
 
-	if (a == &dev_attr_resource.attr) {
-		if (is_namespace_blk(dev))
-			return 0;
-		return 0400;
-	}
+	if (a == &dev_attr_resource.attr && is_namespace_blk(dev))
+		return 0;
 
 	if (is_namespace_pmem(dev) || is_namespace_blk(dev)) {
 		if (a == &dev_attr_size.attr)

drivers/nvdimm/pfn_devs.c

@@ -218,7 +218,7 @@ static ssize_t resource_show(struct device *dev,
 
 	return rc;
 }
-static DEVICE_ATTR_RO(resource);
+static DEVICE_ATTR(resource, 0400, resource_show, NULL);
 
 static ssize_t size_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
@@ -269,16 +269,8 @@ static struct attribute *nd_pfn_attributes[] = {
 	NULL,
 };
 
-static umode_t pfn_visible(struct kobject *kobj, struct attribute *a, int n)
-{
-	if (a == &dev_attr_resource.attr)
-		return 0400;
-	return a->mode;
-}
-
 static struct attribute_group nd_pfn_attribute_group = {
 	.attrs = nd_pfn_attributes,
-	.is_visible = pfn_visible,
 };
 
 const struct attribute_group *nd_pfn_attribute_groups[] = {

drivers/nvdimm/region_devs.c

@@ -553,7 +553,7 @@ static ssize_t resource_show(struct device *dev,
 
 	return sprintf(buf, "%#llx\n", nd_region->ndr_start);
 }
-static DEVICE_ATTR_RO(resource);
+static DEVICE_ATTR(resource, 0400, resource_show, NULL);
 
 static ssize_t persistence_domain_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
@@ -605,12 +605,8 @@ static umode_t region_visible(struct kobject *kobj, struct attribute *a, int n)
 	if (!is_memory(dev) && a == &dev_attr_badblocks.attr)
 		return 0;
 
-	if (a == &dev_attr_resource.attr) {
-		if (is_memory(dev))
-			return 0400;
-		else
-			return 0;
-	}
+	if (a == &dev_attr_resource.attr && !is_memory(dev))
+		return 0;
 
 	if (a == &dev_attr_deep_flush.attr) {
 		int has_flush = nvdimm_has_flush(nd_region);