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authorJonas Meurer <jonas@freesources.org>2020-01-16 12:53:54 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-01-16 21:47:03 +0100
commitc052bf82c6b00ca27aab0859addc4b3159dfd3a4 (patch)
tree5d705708933306bc2c9600133255c8110869bd3a /include/linux/suspend.h
parent5c0e9de06577ba7599b75f97a8bb8cc63f6cb2ad (diff)
PM: suspend: Add sysfs attribute to control the "sync on suspend" behavior
The sysfs attribute `/sys/power/sync_on_suspend` controls, whether or not filesystems are synced by the kernel before system suspend. Congruously, the behaviour of build-time switch CONFIG_SUSPEND_SKIP_SYNC is slightly changed: It now defines the run-tim default for the new sysfs attribute `/sys/power/sync_on_suspend`. The run-time attribute is added because the existing corresponding build-time Kconfig flag for (`CONFIG_SUSPEND_SKIP_SYNC`) is not flexible enough. E.g. Linux distributions that provide pre-compiled kernels usually want to stick with the default (sync filesystems before suspend) but under special conditions this needs to be changed. One example for such a special condition is user-space handling of suspending block devices (e.g. using `cryptsetup luksSuspend` or `dmsetup suspend`) before system suspend. The Kernel trying to sync filesystems after the underlying block device already got suspended obviously leads to dead-locks. Be aware that you have to take care of the filesystem sync yourself before suspending the system in those scenarios. Signed-off-by: Jonas Meurer <jonas@freesources.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'include/linux/suspend.h')
-rw-r--r--include/linux/suspend.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 6fc8843f1c9e..4a230c2f1c31 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -329,6 +329,7 @@ extern void arch_suspend_disable_irqs(void);
extern void arch_suspend_enable_irqs(void);
extern int pm_suspend(suspend_state_t state);
+extern bool sync_on_suspend_enabled;
#else /* !CONFIG_SUSPEND */
#define suspend_valid_only_mem NULL
@@ -342,6 +343,7 @@ static inline bool pm_suspend_default_s2idle(void) { return false; }
static inline void suspend_set_ops(const struct platform_suspend_ops *ops) {}
static inline int pm_suspend(suspend_state_t state) { return -ENOSYS; }
+static inline bool sync_on_suspend_enabled(void) { return true; }
static inline bool idle_should_enter_s2idle(void) { return false; }
static inline void __init pm_states_init(void) {}
static inline void s2idle_set_ops(const struct platform_s2idle_ops *ops) {}