diff options
| -rw-r--r-- | drivers/base/power/runtime.c | 44 |
1 files changed, 37 insertions, 7 deletions
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index d4059e6ffeae..23bea81160e5 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -263,7 +263,7 @@ static int rpm_check_suspend_allowed(struct device *dev) retval = -EINVAL; else if (dev->power.disable_depth > 0) retval = -EACCES; - else if (atomic_read(&dev->power.usage_count) > 0) + else if (atomic_read(&dev->power.usage_count)) retval = -EAGAIN; else if (!dev->power.ignore_children && atomic_read(&dev->power.child_count)) @@ -1039,13 +1039,33 @@ int pm_schedule_suspend(struct device *dev, unsigned int delay) } EXPORT_SYMBOL_GPL(pm_schedule_suspend); +static int rpm_drop_usage_count(struct device *dev) +{ + int ret; + + ret = atomic_sub_return(1, &dev->power.usage_count); + if (ret >= 0) + return ret; + + /* + * Because rpm_resume() does not check the usage counter, it will resume + * the device even if the usage counter is 0 or negative, so it is + * sufficient to increment the usage counter here to reverse the change + * made above. + */ + atomic_inc(&dev->power.usage_count); + dev_warn(dev, "Runtime PM usage count underflow!\n"); + return -EINVAL; +} + /** * __pm_runtime_idle - Entry point for runtime idle operations. * @dev: Device to send idle notification for. * @rpmflags: Flag bits. * * If the RPM_GET_PUT flag is set, decrement the device's usage count and - * return immediately if it is larger than zero. Then carry out an idle + * return immediately if it is larger than zero (if it becomes negative, log a + * warning, increment it, and return an error). Then carry out an idle * notification, either synchronous or asynchronous. * * This routine may be called in atomic context if the RPM_ASYNC flag is set, @@ -1057,7 +1077,10 @@ int __pm_runtime_idle(struct device *dev, int rpmflags) int retval; if (rpmflags & RPM_GET_PUT) { - if (!atomic_dec_and_test(&dev->power.usage_count)) { + retval = rpm_drop_usage_count(dev); + if (retval < 0) { + return retval; + } else if (retval > 0) { trace_rpm_usage_rcuidle(dev, rpmflags); return 0; } @@ -1079,7 +1102,8 @@ EXPORT_SYMBOL_GPL(__pm_runtime_idle); * @rpmflags: Flag bits. * * If the RPM_GET_PUT flag is set, decrement the device's usage count and - * return immediately if it is larger than zero. Then carry out a suspend, + * return immediately if it is larger than zero (if it becomes negative, log a + * warning, increment it, and return an error). Then carry out a suspend, * either synchronous or asynchronous. * * This routine may be called in atomic context if the RPM_ASYNC flag is set, @@ -1091,7 +1115,10 @@ int __pm_runtime_suspend(struct device *dev, int rpmflags) int retval; if (rpmflags & RPM_GET_PUT) { - if (!atomic_dec_and_test(&dev->power.usage_count)) { + retval = rpm_drop_usage_count(dev); + if (retval < 0) { + return retval; + } else if (retval > 0) { trace_rpm_usage_rcuidle(dev, rpmflags); return 0; } @@ -1527,14 +1554,17 @@ EXPORT_SYMBOL_GPL(pm_runtime_forbid); */ void pm_runtime_allow(struct device *dev) { + int ret; + spin_lock_irq(&dev->power.lock); if (dev->power.runtime_auto) goto out; dev->power.runtime_auto = true; - if (atomic_dec_and_test(&dev->power.usage_count)) + ret = rpm_drop_usage_count(dev); + if (ret == 0) rpm_idle(dev, RPM_AUTO | RPM_ASYNC); - else + else if (ret > 0) trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC); out: |