[ndctl PATCH v2 08/18] cxl/list: Skip emitting pmem_size when it is zero

[Dan Williams]

The typical case is that CXL devices are pure ram devices. Only emit
capacity sizes when they are non-zero to avoid confusion around whether
pmem is available via partitioning or not.

The confusion being that a user may assign more meaning to the zero size
value than it actually deserves. A zero value for either pmem or ram,
doesn't indicate the devices capability for either mode.  Use the -I
option to cxl list to include paritition info in the memdev listing.
That will explicitly show the ram and pmem capabilities of the device.

Do the same for ram_size on the odd case that someone builds a pure pmem
device.

Cc: Alison Schofield <alison.schofi...@intel.com>
[alison: clarify changelog]
Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
---
 Documentation/cxl/cxl-list.txt |    5 -----
 cxl/json.c                     |   20 +++++++++++++-------
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/Documentation/cxl/cxl-list.txt b/Documentation/cxl/cxl-list.txt
index 14a2b4bb5c2a..56229abcb053 100644
--- a/Documentation/cxl/cxl-list.txt
+++ b/Documentation/cxl/cxl-list.txt
@@ -70,7 +70,6 @@ configured.
 {
   "memdev":"mem0",
   "pmem_size":"256.00 MiB (268.44 MB)",
-  "ram_size":0,
   "serial":"0",
   "host":"0000:35:00.0"
 }
@@ -88,7 +87,6 @@ EXAMPLE
   {
     "memdev":"mem0",
     "pmem_size":268435456,
-    "ram_size":0,
     "serial":0,
     "host":"0000:35:00.0"
   }
@@ -101,7 +99,6 @@ EXAMPLE
       {
         "memdev":"mem0",
         "pmem_size":"256.00 MiB (268.44 MB)",
-        "ram_size":0,
         "serial":"0"
       }
     ]
@@ -129,7 +126,6 @@ OPTIONS
   {
     "memdev":"mem0",
     "pmem_size":268435456,
-    "ram_size":0,
     "serial":0
   },
   {
@@ -204,7 +200,6 @@ OPTIONS
 [
   {
     "memdev":"mem0",
-    "pmem_size":0,
     "ram_size":273535729664,
     "partition_info":{
       "total_size":273535729664,
diff --git a/cxl/json.c b/cxl/json.c
index 2f3639ede2f8..292e8428ccee 100644
--- a/cxl/json.c
+++ b/cxl/json.c
@@ -305,7 +305,7 @@ struct json_object *util_cxl_memdev_to_json(struct 
cxl_memdev *memdev,
 {
        const char *devname = cxl_memdev_get_devname(memdev);
        struct json_object *jdev, *jobj;
-       unsigned long long serial;
+       unsigned long long serial, size;
        int numa_node;
 
        jdev = json_object_new_object();
@@ -316,13 +316,19 @@ struct json_object *util_cxl_memdev_to_json(struct 
cxl_memdev *memdev,
        if (jobj)
                json_object_object_add(jdev, "memdev", jobj);
 
-       jobj = util_json_object_size(cxl_memdev_get_pmem_size(memdev), flags);
-       if (jobj)
-               json_object_object_add(jdev, "pmem_size", jobj);
+       size = cxl_memdev_get_pmem_size(memdev);
+       if (size) {
+               jobj = util_json_object_size(size, flags);
+               if (jobj)
+                       json_object_object_add(jdev, "pmem_size", jobj);
+       }
 
-       jobj = util_json_object_size(cxl_memdev_get_ram_size(memdev), flags);
-       if (jobj)
-               json_object_object_add(jdev, "ram_size", jobj);
+       size = cxl_memdev_get_ram_size(memdev);
+       if (size) {
+               jobj = util_json_object_size(size, flags);
+               if (jobj)
+                       json_object_object_add(jdev, "ram_size", jobj);
+       }
 
        if (flags & UTIL_JSON_HEALTH) {
                jobj = util_cxl_memdev_health_to_json(memdev, flags);