linux-kernel - [PATCH v2 08/10] PM: sleep: Move some assignments from under a lock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3750318.MHq7AAxBmi@kreacher>
Date: Mon, 29 Jan 2024 17:27:33 +0100
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>, Ulf Hansson <ulf.hansson@...aro.org>, Stanislaw Gruszka <stanislaw.gruszka@...ux.intel.com>
Subject: [PATCH v2 08/10] PM: sleep: Move some assignments from under a lock

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

The async_error and pm_transition variables are set under dpm_list_mtx
in multiple places in the system-wide device PM core code, which is
unnecessary and confusing, so rearrange the code so that the variables
in question are set before acquiring the lock.

While at it, add some empty code lines around locking to improve the
consistency of the code.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---

v1 -> v2: No changes.

---
 drivers/base/power/main.c |   28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

Index: linux-pm/drivers/base/power/main.c
===================================================================
--- linux-pm.orig/drivers/base/power/main.c
+++ linux-pm/drivers/base/power/main.c
@@ -707,9 +707,9 @@ static void dpm_noirq_resume_devices(pm_
 	trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, true);
 
 	async_error = 0;
+	pm_transition = state;
 
 	mutex_lock(&dpm_list_mtx);
-	pm_transition = state;
 
 	/*
 	 * Trigger the resume of "async" devices upfront so they don't have to
@@ -847,9 +847,9 @@ void dpm_resume_early(pm_message_t state
 	trace_suspend_resume(TPS("dpm_resume_early"), state.event, true);
 
 	async_error = 0;
+	pm_transition = state;
 
 	mutex_lock(&dpm_list_mtx);
-	pm_transition = state;
 
 	/*
 	 * Trigger the resume of "async" devices upfront so they don't have to
@@ -1012,10 +1012,11 @@ void dpm_resume(pm_message_t state)
 	trace_suspend_resume(TPS("dpm_resume"), state.event, true);
 	might_sleep();
 
-	mutex_lock(&dpm_list_mtx);
 	pm_transition = state;
 	async_error = 0;
 
+	mutex_lock(&dpm_list_mtx);
+
 	/*
 	 * Trigger the resume of "async" devices upfront so they don't have to
 	 * wait for the "non-async" ones they don't depend on.
@@ -1294,10 +1295,12 @@ static int dpm_noirq_suspend_devices(pm_
 	int error = 0;
 
 	trace_suspend_resume(TPS("dpm_suspend_noirq"), state.event, true);
-	mutex_lock(&dpm_list_mtx);
+
 	pm_transition = state;
 	async_error = 0;
 
+	mutex_lock(&dpm_list_mtx);
+
 	while (!list_empty(&dpm_late_early_list)) {
 		struct device *dev = to_device(dpm_late_early_list.prev);
 
@@ -1320,7 +1323,9 @@ static int dpm_noirq_suspend_devices(pm_
 		if (error || async_error)
 			break;
 	}
+
 	mutex_unlock(&dpm_list_mtx);
+
 	async_synchronize_full();
 	if (!error)
 		error = async_error;
@@ -1470,11 +1475,14 @@ int dpm_suspend_late(pm_message_t state)
 	int error = 0;
 
 	trace_suspend_resume(TPS("dpm_suspend_late"), state.event, true);
-	wake_up_all_idle_cpus();
-	mutex_lock(&dpm_list_mtx);
+
 	pm_transition = state;
 	async_error = 0;
 
+	wake_up_all_idle_cpus();
+
+	mutex_lock(&dpm_list_mtx);
+
 	while (!list_empty(&dpm_suspended_list)) {
 		struct device *dev = to_device(dpm_suspended_list.prev);
 
@@ -1498,7 +1506,9 @@ int dpm_suspend_late(pm_message_t state)
 		if (error || async_error)
 			break;
 	}
+
 	mutex_unlock(&dpm_list_mtx);
+
 	async_synchronize_full();
 	if (!error)
 		error = async_error;
@@ -1745,9 +1755,11 @@ int dpm_suspend(pm_message_t state)
 	devfreq_suspend();
 	cpufreq_suspend();
 
-	mutex_lock(&dpm_list_mtx);
 	pm_transition = state;
 	async_error = 0;
+
+	mutex_lock(&dpm_list_mtx);
+
 	while (!list_empty(&dpm_prepared_list)) {
 		struct device *dev = to_device(dpm_prepared_list.prev);
 
@@ -1771,7 +1783,9 @@ int dpm_suspend(pm_message_t state)
 		if (error || async_error)
 			break;
 	}
+
 	mutex_unlock(&dpm_list_mtx);
+
 	async_synchronize_full();
 	if (!error)
 		error = async_error;