From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752569Ab1GYU4b (ORCPT ); Mon, 25 Jul 2011 16:56:31 -0400 Received: from smtp-out.google.com ([216.239.44.51]:26793 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751578Ab1GYU43 (ORCPT ); Mon, 25 Jul 2011 16:56:29 -0400 From: Colin Cross To: linux-pm@lists.linux-foundation.org Cc: "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, Kevin Hilman , Nishanth Menon , Alan Stern , Colin Cross Subject: [PATCH v2] PM: runtime: add might_sleep to PM runtime functions Date: Mon, 25 Jul 2011 13:55:44 -0700 Message-Id: <1311627344-8097-1-git-send-email-ccross@android.com> X-Mailer: git-send-email 1.7.4.1 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some of the entry points to pm runtime are not safe to call in atomic context unless pm_runtime_irq_safe() has been called. Inspecting the code, it is not immediately obvious that the functions sleep at all, as they run inside a spin_lock_irqsave, but under some conditions they can drop the lock and turn on irqs. If a driver incorrectly calls the pm_runtime apis, it can cause sleeping and irq processing when it expects to stay in atomic context. Add might_sleep_if to all the __pm_runtime_* entry points to enforce correct usage. Add pm_runtime_put_sync_autosuspend to the list of functions that can be called in atomic context. Signed-off-by: Colin Cross --- Documentation/power/runtime_pm.txt | 1 + drivers/base/power/runtime.c | 15 ++++++++++++--- 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index c291233..1ad507c 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -469,6 +469,7 @@ pm_runtime_resume() pm_runtime_get_sync() pm_runtime_put_sync() pm_runtime_put_sync_suspend() +pm_runtime_put_sync_autosuspend() 5. Run-time PM Initialization, Device Probing and Removal diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 2e746f8..f3d8583 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -731,13 +731,16 @@ EXPORT_SYMBOL_GPL(pm_schedule_suspend); * return immediately if it is larger than zero. 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. + * This routine may be called in atomic context if the RPM_ASYNC flag is set, + * or if pm_runtime_irq_safe() has been called. */ int __pm_runtime_idle(struct device *dev, int rpmflags) { unsigned long flags; int retval; + might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe); + if (rpmflags & RPM_GET_PUT) { if (!atomic_dec_and_test(&dev->power.usage_count)) return 0; @@ -760,13 +763,16 @@ EXPORT_SYMBOL_GPL(__pm_runtime_idle); * return immediately if it is larger than zero. Then carry out a suspend, * either synchronous or asynchronous. * - * This routine may be called in atomic context if the RPM_ASYNC flag is set. + * This routine may be called in atomic context if the RPM_ASYNC flag is set, + * or if pm_runtime_irq_safe() has been called. */ int __pm_runtime_suspend(struct device *dev, int rpmflags) { unsigned long flags; int retval; + might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe); + if (rpmflags & RPM_GET_PUT) { if (!atomic_dec_and_test(&dev->power.usage_count)) return 0; @@ -788,13 +794,16 @@ EXPORT_SYMBOL_GPL(__pm_runtime_suspend); * If the RPM_GET_PUT flag is set, increment the device's usage count. Then * carry out a resume, either synchronous or asynchronous. * - * This routine may be called in atomic context if the RPM_ASYNC flag is set. + * This routine may be called in atomic context if the RPM_ASYNC flag is set, + * or if pm_runtime_irq_safe() has been called. */ int __pm_runtime_resume(struct device *dev, int rpmflags) { unsigned long flags; int retval; + might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe); + if (rpmflags & RPM_GET_PUT) atomic_inc(&dev->power.usage_count); -- 1.7.4.1