[PATCH v6 14/18] fs/resctrl: Control visibility of global per-CPU kernel mode group files

[Babu Moger]

The kmode_cpus and kmode_cpus_list files are specific to the
RESCTRL_GLOBAL_ENABLE_PER_CPU kernel mode. These files are created in a
hidden state when an rdtgroup is created.

Introduce resctrl_kmode_global_files_show() to manage the visibility of
these files based on whether the global per-CPU kernel mode is enabled or
disabled.

Suggested-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v6: Helper named for the global per-CPU files instead of unhiding every
    hidden file on the group.
    https://lore.kernel.org/lkml/34aa4824-810b-4c81-8188-f2f37e1dc277@xxxxxxxxx/
---
 fs/resctrl/rdtgroup.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 0cdc868a55b1..98451b417fe3 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1125,6 +1125,24 @@ static int resctrl_kernel_mode_show(struct kernfs_open_file *of,
 	return 0;
 }
 
+/* Show or hide kmode_cpus and kmode_cpus_list on @kn. */
+static void resctrl_kmode_global_files_show(struct kernfs_node *kn, bool show)
+{
+	struct kernfs_node *kn_file;
+
+	kn_file = kernfs_find_and_get(kn, "kmode_cpus");
+	if (kn_file) {
+		kernfs_show(kn_file, show);
+		kernfs_put(kn_file);
+	}
+
+	kn_file = kernfs_find_and_get(kn, "kmode_cpus_list");
+	if (kn_file) {
+		kernfs_show(kn_file, show);
+		kernfs_put(kn_file);
+	}
+}
+
 /*
  * resctrl_kmode_global_online_cpu() - Program kernel mode association for @cpu
  * @cpu: CPU that has just been brought online
@@ -1175,6 +1193,7 @@ static void rdtgroup_kmode_global_deactivate(struct rdtgroup *rdtgrp)
 {
 	resctrl_configure_kmode_global(&rdtgrp->kmode_cpu_mask, rdtgrp, false);
 	cpumask_clear(&rdtgrp->kmode_cpu_mask);
+	resctrl_kmode_global_files_show(rdtgrp->kn, false);
 }
 
 /*
-- 
2.43.0