[PATCH v3 14/38] x86/resctrl: Add a resctrl helper to reset all the resources

[James Morse]

On umount(), resctrl resets each resource back to its default
configuration. It only ever does this for all resources in one go.

reset_all_ctrls() is architecture specific as it works with struct
rdt_hw_resource.

Add an architecture helper to reset all resources.

Co-developed-by: Dave Martin <Dave.Martin@xxxxxxx>
Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>
Signed-off-by: James Morse <james.morse@xxxxxxx>
Tested-by: Peter Newman <peternewman@xxxxxxxxxx>
Tested-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
---
Changes since v1:
 * Rename the for_each_capable_rdt_resource() introduced in the new
   function resctrl_arch_reset_resources(), back to
   for_each_alloc_capable_rdt_resource() as it was in the original code.

   The change looked unintentional; and presumably a resource that does
   not support resource allocation doesn't have any properties to
   reset...
---
 arch/x86/include/asm/resctrl.h         |  2 ++
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 16 +++++++++++-----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/resctrl.h b/arch/x86/include/asm/resctrl.h
index f61382258743..5f6a5375bb4a 100644
--- a/arch/x86/include/asm/resctrl.h
+++ b/arch/x86/include/asm/resctrl.h
@@ -15,6 +15,8 @@
  */
 #define X86_RESCTRL_EMPTY_CLOSID         ((u32)~0)
 
+void resctrl_arch_reset_resources(void);
+
 /**
  * struct resctrl_pqr_state - State cache for the PQR MSR
  * @cur_rmid:		The cached Resource Monitoring ID
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 1574f5afd0e8..82d64885c6c0 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2886,6 +2886,14 @@ static int reset_all_ctrls(struct rdt_resource *r)
 	return 0;
 }
 
+void resctrl_arch_reset_resources(void)
+{
+	struct rdt_resource *r;
+
+	for_each_alloc_capable_rdt_resource(r)
+		reset_all_ctrls(r);
+}
+
 /*
  * Move tasks from one to the other group. If @from is NULL, then all tasks
  * in the systems are moved unconditionally (used for teardown).
@@ -2995,16 +3003,14 @@ static void rmdir_all_sub(void)
 
 static void rdt_kill_sb(struct super_block *sb)
 {
-	struct rdt_resource *r;
-
 	cpus_read_lock();
 	mutex_lock(&rdtgroup_mutex);
 
 	rdt_disable_ctx();
 
-	/*Put everything back to default values. */
-	for_each_alloc_capable_rdt_resource(r)
-		reset_all_ctrls(r);
+	/* Put everything back to default values. */
+	resctrl_arch_reset_resources();
+
 	rmdir_all_sub();
 	rdt_pseudo_lock_release();
 	rdtgroup_default.mode = RDT_MODE_SHAREABLE;
-- 
2.39.2