[PATCH 09/12] 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 an is_visible() 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")
Cc: stable@vger.kernel.org # 7.0
Signed-off-by: Srish Srinivasan <ssrish@linux.ibm.com>
Tested-by: R Nageswara Sastry <rnsastry@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