[PATCH 5/8] pseries/plpks: hide wrapping_features when unsupported

[Srish Srinivasan <ssrish@linux.ibm.com>]

The PLPKS wrapping features config is only valid on systems that support
the "Key Wrapping" feature. Currently the config is always exposed, even
when the feature is unavailable.

Add is_visible attribute_group callback to suppress the wrapping features
sysfs attribute when the "Key Wrapping" feature is not supported. Declare
the attribute group static const, as it is not modified after
initialization.

Fixes: 447eb1d5ef00 ("pseries/plpks: expose PowerVM wrapping features via the sysfs")
Signed-off-by: Srish Srinivasan <ssrish@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/plpks-sysfs.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/plpks-sysfs.c b/arch/powerpc/platforms/pseries/plpks-sysfs.c
index c2ebcbb41ae3..f2436229f323 100644
--- a/arch/powerpc/platforms/pseries/plpks-sysfs.c
+++ b/arch/powerpc/platforms/pseries/plpks-sysfs.c
@@ -45,6 +45,16 @@ static const struct attribute *config_attrs[] = {
 
 static struct kobject *plpks_kobj, *plpks_config_kobj;
 
+static umode_t plpks_config_attr_is_visible(struct kobject *kobj,
+					    struct attribute *attr, int n)
+{
+	if (attr == &attr_wrapping_features.attr &&
+	    !plpks_wrapping_is_supported())
+		return 0;
+
+	return attr->mode;
+}
+
 int plpks_config_create_softlink(struct kobject *from)
 {
 	if (!plpks_config_kobj)
@@ -52,13 +62,13 @@ int plpks_config_create_softlink(struct kobject *from)
 	return sysfs_create_link(from, plpks_config_kobj, "config");
 }
 
+static const struct attribute_group config_group = {
+	.attrs = (struct attribute **)config_attrs,
+	.is_visible = plpks_config_attr_is_visible,
+};
+
 static __init int plpks_sysfs_config(struct kobject *kobj)
 {
-	struct attribute_group config_group = {
-		.name = NULL,
-		.attrs = (struct attribute **)config_attrs,
-	};
-
 	return sysfs_create_group(kobj, &config_group);
 }
 
-- 
2.52.0