[PATCH] [ndctl PATCH v2] ndctl/list: display region caps for any of BTT, PFN, DAX

[Donet Tom <donettom@linux.vnet.ibm.com>]

If any one of BTT, PFN, or DAX is not present, but the other two
are, then the region capabilities are not displayed in the
ndctl list -R -C command.

This is because util_region_capabilities_to_json() returns NULL
if any one of BTT, PFN, or DAX is not present.

In this patch, we have changed the logic to display all the region
capabilities that are present.

Test Results with CONFIG_BTT disabled
=====================================
Without this patch
------------------
 # ./ndctl list -R -C
 [
  {
    "dev":"region1",
    "size":12884901888,
    "align":16777216,
    "available_size":11257511936,
    "max_available_extent":9630121984,
    "type":"pmem",
    "iset_id":14748366918514061582,
    "persistence_domain":"unknown"
  },

With this patch
---------------
 # ./ndctl list -R -C
 [
  {
    "dev":"region1",
    "size":12884901888,
    "align":16777216,
    "available_size":11257511936,
    "max_available_extent":9630121984,
    "type":"pmem",
    "iset_id":14748366918514061582,
    "capabilities":[
      {
        "mode":"fsdax",
        "alignments":[
          65536,
          2097152,
          1073741824
        ]
      },
      {
        "mode":"devdax",
        "alignments":[
          65536,
          2097152,
          1073741824
        ]
      }
    ],
    "persistence_domain":"unknown"
  },

v1 -> v2:
Addressed the review comments from Jeff and Alison.

v1:
https://lore.kernel.org/all/20250219094049.5156-1-donettom@linux.ibm.com/

Fixes: 965fa02e372f ("util: Distribute 'filter' and 'json' helpers to per-tool objects")
Signed-off-by: Donet Tom <donettom@linux.vnet.ibm.com>
---
 ndctl/json.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ndctl/json.c b/ndctl/json.c
index 23bad7f..7646882 100644
--- a/ndctl/json.c
+++ b/ndctl/json.c
@@ -381,7 +381,7 @@ struct json_object *util_region_capabilities_to_json(struct ndctl_region *region
 	struct ndctl_pfn *pfn = ndctl_region_get_pfn_seed(region);
 	struct ndctl_dax *dax = ndctl_region_get_dax_seed(region);
 
-	if (!btt || !pfn || !dax)
+	if (!btt && !pfn && !dax)
 		return NULL;
 
 	jcaps = json_object_new_array();
-- 
2.47.1