[PATCH v6 08/10] fs/resctrl: Call architecture hooks for every mount/unmount

[Tony Luck <tony.luck@intel.com>]

Architecture code for AET needs to acquire INTEL_PMT_TELEMETRY module
references on mount and release them on unmount.

Add hooks for every mount/unmount of the resctrl file system so that
architecture code can allocate on mount and free on unmount.

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 include/linux/resctrl.h | 7 +++++--
 fs/resctrl/rdtgroup.c   | 9 +++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 9534d42e0c57..e8a87c3664db 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -552,12 +552,15 @@ void resctrl_online_cpu(unsigned int cpu);
 void resctrl_offline_cpu(unsigned int cpu);
 
 /*
- * Architecture hook called at beginning of first file system mount attempt.
+ * Architecture hook called before attempting to mount the file system.
  * No locks are held.
  */
 void resctrl_arch_pre_mount(void);
 
-/* Called to report unmount. */
+/*
+ * Architecture hook called when mount fails, or on unmount.
+ * No locks are held.
+ */
 void resctrl_arch_unmount(void);
 
 /**
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 2e31ff753114..134ad69de194 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -18,7 +18,6 @@
 #include <linux/fs_parser.h>
 #include <linux/sysfs.h>
 #include <linux/kernfs.h>
-#include <linux/once.h>
 #include <linux/resctrl.h>
 #include <linux/seq_buf.h>
 #include <linux/seq_file.h>
@@ -2790,7 +2789,7 @@ static int rdt_get_tree(struct fs_context *fc)
 	struct rdt_resource *r;
 	int ret;
 
-	DO_ONCE_SLEEPABLE(resctrl_arch_pre_mount);
+	resctrl_arch_pre_mount();
 
 	cpus_read_lock();
 	mutex_lock(&rdtgroup_mutex);
@@ -2899,6 +2898,10 @@ static int rdt_get_tree(struct fs_context *fc)
 	rdt_last_cmd_clear();
 	mutex_unlock(&rdtgroup_mutex);
 	cpus_read_unlock();
+
+	if (ret)
+		resctrl_arch_unmount();
+
 	return ret;
 }
 
@@ -3191,6 +3194,8 @@ static void rdt_kill_sb(struct super_block *sb)
 	kernfs_kill_sb(sb);
 	mutex_unlock(&rdtgroup_mutex);
 	cpus_read_unlock();
+
+	resctrl_arch_unmount();
 }
 
 static struct file_system_type rdt_fs_type = {
-- 
2.53.0