[PATCH ndctl RESEND 2/2] cxl/region: Fix memory device teardown in disable-region

[Ira Weiny]

When a region is requested to be disabled, memory devices are normally
automatically torn down.  Commit 9399aa667ab0 prevents tear down if
memory is online without a force flag.  However, daxctl_dev_get_memory()
may return NULL if the memory device in question is not system-ram
capable as is the case for a region with only devdax devices.  Such
devices do not need to be off-lined explicitly.

Skip non-system-ram devices rather than error the operation.

Fixes: 9399aa667ab0 ("cxl/region: Add -f option for disable-region")
Cc: Dave Jiang <dave.ji...@intel.com>
Signed-off-by: Ira Weiny <ira.we...@intel.com>
---
 cxl/region.c             | 3 +++
 daxctl/lib/libdaxctl.c   | 4 ++--
 daxctl/lib/libdaxctl.sym | 5 +++++
 daxctl/libdaxctl.h       | 1 +
 4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/cxl/region.c b/cxl/region.c
index 5cbbf2749e2d..44ac76b001e9 100644
--- a/cxl/region.c
+++ b/cxl/region.c
@@ -805,6 +805,9 @@ static int disable_region(struct cxl_region *region)
                goto out;
 
        daxctl_dev_foreach(dax_region, dev) {
+               if (!daxctl_dev_is_system_ram_capable(dev))
+                       continue;
+
                mem = daxctl_dev_get_memory(dev);
                if (!mem)
                        return -ENXIO;
diff --git a/daxctl/lib/libdaxctl.c b/daxctl/lib/libdaxctl.c
index 4f9aba0b09f2..9fbefe2e8329 100644
--- a/daxctl/lib/libdaxctl.c
+++ b/daxctl/lib/libdaxctl.c
@@ -385,7 +385,7 @@ static bool device_model_is_dax_bus(struct daxctl_dev *dev)
        return false;
 }
 
-static int dev_is_system_ram_capable(struct daxctl_dev *dev)
+DAXCTL_EXPORT int daxctl_dev_is_system_ram_capable(struct daxctl_dev *dev)
 {
        const char *devname = daxctl_dev_get_devname(dev);
        struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
@@ -432,7 +432,7 @@ static struct daxctl_memory *daxctl_dev_alloc_mem(struct 
daxctl_dev *dev)
        char buf[SYSFS_ATTR_SIZE];
        int node_num;
 
-       if (!dev_is_system_ram_capable(dev))
+       if (!daxctl_dev_is_system_ram_capable(dev))
                return NULL;
 
        mem = calloc(1, sizeof(*mem));
diff --git a/daxctl/lib/libdaxctl.sym b/daxctl/lib/libdaxctl.sym
index fe68fd0a9cde..309881196c86 100644
--- a/daxctl/lib/libdaxctl.sym
+++ b/daxctl/lib/libdaxctl.sym
@@ -99,3 +99,8 @@ global:
        daxctl_set_config_path;
        daxctl_get_config_path;
 } LIBDAXCTL_8;
+
+LIBDAXCTL_10 {
+global:
+       daxctl_dev_is_system_ram_capable;
+} LIBDAXCTL_9;
diff --git a/daxctl/libdaxctl.h b/daxctl/libdaxctl.h
index 6876037a9427..53c6bbdae5c3 100644
--- a/daxctl/libdaxctl.h
+++ b/daxctl/libdaxctl.h
@@ -77,6 +77,7 @@ int daxctl_dev_will_auto_online_memory(struct daxctl_dev 
*dev);
 int daxctl_dev_has_online_memory(struct daxctl_dev *dev);
 
 struct daxctl_memory;
+int daxctl_dev_is_system_ram_capable(struct daxctl_dev *dev);
 struct daxctl_memory *daxctl_dev_get_memory(struct daxctl_dev *dev);
 struct daxctl_dev *daxctl_memory_get_dev(struct daxctl_memory *mem);
 const char *daxctl_memory_get_node_path(struct daxctl_memory *mem);

-- 
2.42.0