projects/linux·commit ec857209

Merge tag 'pm-5.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

ec857209 · Linus Torvalds <[email protected]> · 2021-03-19 10:00:10 -07:00

Pull power management fixes from Rafael Wysocki:
 "Revert two problematic commits.

  Specifics:

   - Revert ACPI PM commit that attempted to improve reboot handling on
     some systems, but it caused other systems to panic() during reboot
     (Josef Bacik)

   - Revert PM-runtime commit that attempted to improve the handling of
     suppliers during PM-runtime suspend of a consumer device, but it
     introduced a race condition potentially leading to unexpected
     behavior (Rafael Wysocki)"

* tag 'pm-5.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "PM: runtime: Update device status before letting suppliers suspend"
  Revert "PM: ACPI: reboot: Use S5 for reboot"
Commit
ec85720933863015b1c26bc19cf4e044da139bc5
Parents
65a10374 · 49cb71a7

Merge commit. Changes below are compared with the first parent: 65a10374.

Changes

2 files changed · +25 −39

FileStatusAddDelContent
drivers/base/power/runtime.cmodified+25−37View file
kernel/reboot.cmodified+0−2View file

drivers/base/power/runtime.c

View file
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 18b8242..a46a7e3 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -325,22 +325,22 @@ static void rpm_put_suppliers(struct device *dev)
static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
__releases(&dev->power.lock) __acquires(&dev->power.lock)
{
- bool use_links = dev->power.links_count > 0;
- bool get = false;
int retval, idx;
- bool put;
+ bool use_links = dev->power.links_count > 0;
if (dev->power.irq_safe) {
spin_unlock(&dev->power.lock);
- } else if (!use_links) {
- spin_unlock_irq(&dev->power.lock);
} else {
- get = dev->power.runtime_status == RPM_RESUMING;
-
spin_unlock_irq(&dev->power.lock);
- /* Resume suppliers if necessary. */
- if (get) {
+ /*
+ * Resume suppliers if necessary.
+ *
+ * The device's runtime PM status cannot change until this
+ * routine returns, so it is safe to read the status outside of
+ * the lock.
+ */
+ if (use_links && dev->power.runtime_status == RPM_RESUMING) {
idx = device_links_read_lock();
retval = rpm_get_suppliers(dev);
@@ -355,36 +355,24 @@ static int __rpm_callback(int (*cb)(struct device *), struct device *dev)
if (dev->power.irq_safe) {
spin_lock(&dev->power.lock);
- return retval;
- }
-
- spin_lock_irq(&dev->power.lock);
-
- if (!use_links)
- return retval;
-
- /*
- * If the device is suspending and the callback has returned success,
- * drop the usage counters of the suppliers that have been reference
- * counted on its resume.
- *
- * Do that if the resume fails too.
- */
- put = dev->power.runtime_status == RPM_SUSPENDING && !retval;
- if (put)
- __update_runtime_status(dev, RPM_SUSPENDED);
- else
- put = get && retval;
-
- if (put) {
- spin_unlock_irq(&dev->power.lock);
-
- idx = device_links_read_lock();
+ } else {
+ /*
+ * If the device is suspending and the callback has returned
+ * success, drop the usage counters of the suppliers that have
+ * been reference counted on its resume.
+ *
+ * Do that if resume fails too.
+ */
+ if (use_links
+ && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)
+ || (dev->power.runtime_status == RPM_RESUMING && retval))) {
+ idx = device_links_read_lock();
-fail:
- rpm_put_suppliers(dev);
+ fail:
+ rpm_put_suppliers(dev);
- device_links_read_unlock(idx);
+ device_links_read_unlock(idx);
+ }
spin_lock_irq(&dev->power.lock);
}

kernel/reboot.c

View file
diff --git a/kernel/reboot.c b/kernel/reboot.c
index eb1b158..a6ad5eb 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -244,8 +244,6 @@ void migrate_to_reboot_cpu(void)
void kernel_restart(char *cmd)
{
kernel_restart_prepare(cmd);
- if (pm_power_off_prepare)
- pm_power_off_prepare();
migrate_to_reboot_cpu();
syscore_shutdown();
if (!cmd)