Re: [PATCH] ndctl: json: Region capabilities are not displayed if any of the BTT, PFN, or DAX are not present

[Donet Tom]

On 2/19/25 22:10, Jeff Moyer wrote:

Donet Tom <donet...@linux.ibm.com> writes:

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
------------------
  # ./build/ndctl/ndctl  list -R -C
  [
   {
     "dev":"region1",
     "size":549755813888,
     "align":16777216,
     "available_size":549755813888,
     "max_available_extent":549755813888,
     "type":"pmem",
     "iset_id":11510624209454722969,
     "persistence_domain":"memory_controller"
   },

With this patch
---------------
  # ./build/ndctl/ndctl  list -R -C
  [
   {
     "dev":"region1",
     "size":549755813888,
     "align":16777216,
     "available_size":549755813888,
     "max_available_extent":549755813888,
     "type":"pmem",
     "iset_id":11510624209454722969,
     "capabilities":[
       {
         "mode":"fsdax",
         "alignments":[
           65536,
           16777216
         ]
       },
       {
         "mode":"devdax",
         "alignments":[
           65536,
           16777216
         ]
       }
     ],
     "persistence_domain":"memory_controller"
   },

Signed-off-by: Donet Tom <donet...@linux.ibm.com>
---
  ndctl/json.c | 6 ++----
  1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/ndctl/json.c b/ndctl/json.c
index 23bad7f..3df3bc4 100644
--- a/ndctl/json.c
+++ b/ndctl/json.c
@@ -381,9 +381,6 @@ 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)

-               return NULL;
-

I think this was meant to be:

        if (!btt && !pfn && !dax)
                return NULL;

I think that would be the more appropriate fix.

Yes. I will add it and send V2.

Cheers,
Jeff

        jcaps = json_object_new_array();
        if (!jcaps)
                return NULL;
@@ -436,7 +433,8 @@ struct json_object *util_region_capabilities_to_json(struct 
ndctl_region *region
                json_object_object_add(jcap, "alignments", jobj);
        }

- return jcaps;

+       if (btt || pfn || dax)
+               return jcaps;
  err:
        json_object_put(jcaps);
        return NULL;