linux-kernel - [PATCH v1] PM: suspend: clean up redundant filesystems

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Message-Id: <20250712030824.81474-1-zhangzihuan@kylinos.cn>
Date: Sat, 12 Jul 2025 11:08:24 +0800
From: Zihuan Zhang <zhangzihuan@...inos.cn>
To: "Rafael J . Wysocki" <rafael@...nel.org>,
	Christian Brauner <brauner@...nel.org>
Cc: Len Brown <len.brown@...el.com>,
	Pavel Machek <pavel@...nel.org>,
	linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Zihuan Zhang <zhangzihuan@...inos.cn>
Subject: [PATCH v1] PM: suspend: clean up redundant filesystems_freeze/thaw handling

The recently introduced support for freezing filesystems during system
suspend included calls to filesystems_freeze() in both suspend_prepare()
and enter_state(), as well as calls to filesystems_thaw() in both
suspend_finish() and the Unlock path in enter_state(). These are
redundant.

- filesystems_freeze() is already called in suspend_prepare(), which is
  the proper and consistent place to handle pre-suspend operations. The
second call in enter_state() is unnecessary and removed.

- filesystems_thaw() is invoked in suspend_finish(), which covers
  successful suspend/resume paths. In the failure case , we add a call
to filesystems_thaw() only when needed, avoiding the duplicate call in
the general Unlock path.

This change simplifies the suspend code and avoids repeated freeze/thaw
calls, while preserving correct ordering and behavior.

Fixes: eacfbf74196f91e4c26d9f8c78e1576c1225cd8c ("power: freeze filesystems during suspend/resume")
Signed-off-by: Zihuan Zhang <zhangzihuan@...inos.cn>
---
 kernel/power/suspend.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index bb608b68fb30..8f3e4c48d5cd 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -384,6 +384,7 @@ static int suspend_prepare(suspend_state_t state)
 		return 0;
 
 	dpm_save_failed_step(SUSPEND_FREEZE);
+	filesystems_thaw();
 	pm_notifier_call_chain(PM_POST_SUSPEND);
  Restore:
 	pm_restore_console();
@@ -593,8 +594,6 @@ static int enter_state(suspend_state_t state)
 		ksys_sync_helper();
 		trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 	}
-	if (filesystem_freeze_enabled)
-		filesystems_freeze();
 
 	pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
 	pm_suspend_clear_flags();
@@ -614,7 +613,6 @@ static int enter_state(suspend_state_t state)
 	pm_pr_dbg("Finishing wakeup.\n");
 	suspend_finish();
  Unlock:
-	filesystems_thaw();
 	mutex_unlock(&system_transition_mutex);
 	return error;
 }
-- 
2.25.1