[PATCH v7 2/2] PM: Call pm_sleep_fs_sync() instead of ksys_sync_helper()

[Samuel Wu <wusamuel@google.com>]

Replace the direct calls to ksys_sync_helper() with the new
pm_sleep_fs_sync() in suspend, hibernation, and snapshot code paths.
This enables the new polling mechanism that allows for the filesystem
sync phase to be interrupted.

Suggested-by: Saravana Kannan <saravanak@google.com>
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Samuel Wu <wusamuel@google.com>
---
 kernel/power/hibernate.c | 6 +++++-
 kernel/power/suspend.c   | 6 +++++-
 kernel/power/user.c      | 4 +++-
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 26e45f86b955..af8d07bafe02 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -820,7 +820,10 @@ int hibernate(void)
 	if (error)
 		goto Restore;
 
-	ksys_sync_helper();
+	error = pm_sleep_fs_sync();
+	if (error)
+		goto Notify;
+
 	filesystems_freeze(filesystem_freeze_enabled);
 
 	error = freeze_processes();
@@ -891,6 +894,7 @@ int hibernate(void)
 	freezer_test_done = false;
  Exit:
 	filesystems_thaw();
+ Notify:
 	pm_notifier_call_chain(PM_POST_HIBERNATION);
  Restore:
 	pm_restore_console();
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index d9461447e37b..2da4482bb6eb 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -593,7 +593,11 @@ static int enter_state(suspend_state_t state)
 
 	if (sync_on_suspend_enabled) {
 		trace_suspend_resume(TPS("sync_filesystems"), 0, true);
-		ksys_sync_helper();
+
+		error = pm_sleep_fs_sync();
+		if (error)
+			goto Unlock;
+
 		trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 	}
 
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 3f9e3efb9f6e..4401cfe26e5c 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -278,7 +278,9 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 		if (data->frozen)
 			break;
 
-		ksys_sync_helper();
+		error = pm_sleep_fs_sync();
+		if (error)
+			break;
 
 		error = freeze_processes();
 		if (error)
-- 
2.52.0.rc1.455.g30608eb744-goog