[ndctl,4/8] ndctl: use the pfn trimmed size for memory mode namespaces

Commit Message

Dan Williams March 8, 2016, 11:36 p.m. UTC

If the kernel reports the size of the namespace after the memmap
allocation is removed use that value, otherwise don't emit raw namespace
size since it is not accurate.

For the btt case, the effective size is further constrained by the
sector geometry, so userspace should just use the block device size.
Otherwise, the size and base address of the namespace is useful for
hypervisors that want to establish their own host-physical-address
mappings for a guest to consume.

Signed-off-by: Dan Williams <[e-mail]>
---
 util/json.c |   24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

Patch

diff --git a/util/json.c b/util/json.c
index b9a5e75164d8..288efee723ff 100644
--- a/util/json.c
+++ b/util/json.c
@@ -1,3 +1,4 @@ 
+#include <limits.h>
 #include <util/json.h>
 #include <uuid/uuid.h>
 #include <json-c/json.h>
@@ -76,6 +77,8 @@  bool util_namespace_active(struct ndctl_namespace *ndns)
 struct json_object *util_namespace_to_json(struct ndctl_namespace *ndns)
 {
 	struct json_object *jndns = json_object_new_object();
+	unsigned long long size = ULLONG_MAX;
+	enum ndctl_namespace_mode mode;
 	struct json_object *jobj;
 	const char *bdev = NULL;
 	struct ndctl_btt *btt;
@@ -91,14 +94,22 @@  struct json_object *util_namespace_to_json(struct ndctl_namespace *ndns)
 		goto err;
 	json_object_object_add(jndns, "dev", jobj);
 
-	switch (ndctl_namespace_get_mode(ndns)) {
+	btt = ndctl_namespace_get_btt(ndns);
+	pfn = ndctl_namespace_get_pfn(ndns);
+	mode = ndctl_namespace_get_mode(ndns);
+	switch (mode) {
 	case NDCTL_NS_MODE_MEMORY:
+		if (pfn) /* dynamic memory mode */
+			size = ndctl_pfn_get_size(pfn);
+		else /* native/static memory mode */
+			size = ndctl_namespace_get_size(ndns);
 		jobj = json_object_new_string("memory");
 		break;
 	case NDCTL_NS_MODE_SAFE:
 		jobj = json_object_new_string("sector");
 		break;
 	case NDCTL_NS_MODE_RAW:
+		size = ndctl_namespace_get_size(ndns);
 		jobj = json_object_new_string("raw");
 		break;
 	default:
@@ -107,13 +118,12 @@  struct json_object *util_namespace_to_json(struct ndctl_namespace *ndns)
 	if (jobj)
 		json_object_object_add(jndns, "mode", jobj);
 
-	jobj = json_object_new_int64(ndctl_namespace_get_size(ndns));
-	if (!jobj)
-		goto err;
-	json_object_object_add(jndns, "size", jobj);
+	if (size < ULLONG_MAX) {
+		jobj = json_object_new_int64(size);
+		if (jobj)
+			json_object_object_add(jndns, "size", jobj);
+	}
 
-	btt = ndctl_namespace_get_btt(ndns);
-	pfn = ndctl_namespace_get_pfn(ndns);
 	if (btt) {
 		ndctl_btt_get_uuid(btt, uuid);
 		uuid_unparse(uuid, buf);