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: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index d4e54053d009faf3ad1acd663f022e7daeed8e4e..0b78f72ad39d3ccb3629af5c9d2aafb85ed8a78f 100644 (file)
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -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);

diff --git a/kernel/power/user.c b/kernel/power/user.c
index 63368163e98d06bc542b40911e365e9d226f9b35..72e8f4fd616dee0cec880d442e33127602601f6c 100644 (file)
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -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;

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index ca1dd3aa5eee89a924da879735d59b26cd96387f..53ad1325d7a7632fa0acf6835998a9ec58ed5aad 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -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);
 }