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
......@@ -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);
......
......@@ -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;
......
......@@ -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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