Commit 942f4015 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

PM / hibernate / memory hotplug: Rework mutual exclusion 



Since all of the memory hotplug operations have to be carried out
under device_hotplug_lock, they won't need to acquire pm_mutex if
device_hotplug_lock is held around hibernation.

For this reason, make the hibernation code acquire
device_hotplug_lock after freezing user space processes and
release it before thawing them.  At the same tim drop the
lock_system_sleep() and unlock_system_sleep() calls from
lock_memory_hotplug() and unlock_memory_hotplug(), respectively.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: default avatarToshi Kani <toshi.kani@hp.com>
parent 8fd37a4c

kernel/power/hibernate.c

+4 −0
Original line number Diff line number Diff line
@@ -652,6 +652,7 @@ int hibernate(void) 
	if (error)

		goto Exit;



	lock_device_hotplug();

	/* Allocate memory management structures */

	error = create_basic_memory_bitmaps();

	if (error)
@@ -685,6 +686,7 @@ int hibernate(void) 
 Free_bitmaps:

	free_basic_memory_bitmaps();

 Thaw:

	unlock_device_hotplug();

	thaw_processes();



	/* Don't bother checking whether freezer_test_done is true */
@@ -814,6 +816,7 @@ static int software_resume(void) 


	pr_debug("PM: Loading hibernation image.\n");



	lock_device_hotplug();

	error = create_basic_memory_bitmaps();

	if (error)

		goto Thaw;
@@ -827,6 +830,7 @@ static int software_resume(void) 
	swsusp_free();

	free_basic_memory_bitmaps();

 Thaw:

	unlock_device_hotplug();

	thaw_processes();

 Finish:

	pm_notifier_call_chain(PM_POST_RESTORE);

kernel/power/user.c

+2 −0
Original line number Diff line number Diff line
@@ -201,6 +201,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, 
	if (!mutex_trylock(&pm_mutex))

		return -EBUSY;



	lock_device_hotplug();

	data = filp->private_data;



	switch (cmd) {
@@ -373,6 +374,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, 


	}



	unlock_device_hotplug();

	mutex_unlock(&pm_mutex);



	return error;

mm/memory_hotplug.c

+0 −4
Original line number Diff line number Diff line
@@ -51,14 +51,10 @@ DEFINE_MUTEX(mem_hotplug_mutex); 
void lock_memory_hotplug(void)

{

	mutex_lock(&mem_hotplug_mutex);



	/* for exclusive hibernation if CONFIG_HIBERNATION=y */

	lock_system_sleep();

}



void unlock_memory_hotplug(void)

{

	unlock_system_sleep();

	mutex_unlock(&mem_hotplug_mutex);

}

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