From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756952AbcJ3QVn (ORCPT ); Sun, 30 Oct 2016 12:21:43 -0400 Received: from cloudserver094114.home.net.pl ([79.96.170.134]:46036 "HELO cloudserver094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1756710AbcJ3QVk (ORCPT ); Sun, 30 Oct 2016 12:21:40 -0400 From: "Rafael J. Wysocki" To: Linux PM list , Greg Kroah-Hartman Cc: Alan Stern , Linux Kernel Mailing List , Tomeu Vizoso , Mark Brown , Marek Szyprowski , Lukas Wunner , Kevin Hilman , Ulf Hansson , "Luis R. Rodriguez" Subject: [Resend][PATCH v6 3/5] PM / sleep: Make async suspend/resume of devices use device links Date: Sun, 30 Oct 2016 17:28:49 +0100 Message-ID: <15248345.83kz8ia4Vc@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/4.9.0-rc2+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <11468990.WB1J8sxXpS@vostro.rjw.lan> References: <27296716.H9VWo8ShOm@vostro.rjw.lan> <11468990.WB1J8sxXpS@vostro.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki Make the device suspend/resume part of the core system suspend/resume code use device links to ensure that supplier and consumer devices will be suspended and resumed in the right order in case of async suspend/resume. The idea, roughly, is to use dpm_wait() to wait for all consumers before a supplier device suspend and to wait for all suppliers before a consumer device resume. Signed-off-by: Rafael J. Wysocki Tested-by: Marek Szyprowski --- drivers/base/power/main.c | 85 ++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 79 insertions(+), 6 deletions(-) Index: linux-pm/drivers/base/power/main.c =================================================================== --- linux-pm.orig/drivers/base/power/main.c +++ linux-pm/drivers/base/power/main.c @@ -246,6 +246,62 @@ static void dpm_wait_for_children(struct device_for_each_child(dev, &async, dpm_wait_fn); } +static void dpm_wait_for_suppliers(struct device *dev, bool async) +{ + struct device_link *link; + int idx; + + idx = device_links_read_lock(); + + /* + * If the supplier goes away right after we've checked the link to it, + * we'll wait for its completion to change the state, but that's fine, + * because the only things that will block as a result are the SRCU + * callbacks freeing the link objects for the links in the list we're + * walking. + */ + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) + if (READ_ONCE(link->status) != DL_STATE_DORMANT) + dpm_wait(link->supplier, async); + + device_links_read_unlock(idx); +} + +static void dpm_wait_for_superior(struct device *dev, bool async) +{ + dpm_wait(dev->parent, async); + dpm_wait_for_suppliers(dev, async); +} + +static void dpm_wait_for_consumers(struct device *dev, bool async) +{ + struct device_link *link; + int idx; + + idx = device_links_read_lock(); + + /* + * The status of a device link can only be changed from "dormant" by a + * probe, but that cannot happen during system suspend/resume. In + * theory it can change to "dormant" at that time, but then it is + * reasonable to wait for the target device anyway (eg. if it goes + * away, it's better to wait for it to go away completely and then + * continue instead of trying to continue in parallel with its + * unregistration). + */ + list_for_each_entry_rcu(link, &dev->links.consumers, s_node) + if (READ_ONCE(link->status) != DL_STATE_DORMANT) + dpm_wait(link->consumer, async); + + device_links_read_unlock(idx); +} + +static void dpm_wait_for_subordinate(struct device *dev, bool async) +{ + dpm_wait_for_children(dev, async); + dpm_wait_for_consumers(dev, async); +} + /** * pm_op - Return the PM operation appropriate for given PM event. * @ops: PM operations to choose from. @@ -490,7 +546,7 @@ static int device_resume_noirq(struct de if (!dev->power.is_noirq_suspended) goto Out; - dpm_wait(dev->parent, async); + dpm_wait_for_superior(dev, async); if (dev->pm_domain) { info = "noirq power domain "; @@ -620,7 +676,7 @@ static int device_resume_early(struct de if (!dev->power.is_late_suspended) goto Out; - dpm_wait(dev->parent, async); + dpm_wait_for_superior(dev, async); if (dev->pm_domain) { info = "early power domain "; @@ -752,7 +808,7 @@ static int device_resume(struct device * goto Complete; } - dpm_wait(dev->parent, async); + dpm_wait_for_superior(dev, async); dpm_watchdog_set(&wd, dev); device_lock(dev); @@ -1040,7 +1096,7 @@ static int __device_suspend_noirq(struct if (dev->power.syscore || dev->power.direct_complete) goto Complete; - dpm_wait_for_children(dev, async); + dpm_wait_for_subordinate(dev, async); if (dev->pm_domain) { info = "noirq power domain "; @@ -1187,7 +1243,7 @@ static int __device_suspend_late(struct if (dev->power.syscore || dev->power.direct_complete) goto Complete; - dpm_wait_for_children(dev, async); + dpm_wait_for_subordinate(dev, async); if (dev->pm_domain) { info = "late power domain "; @@ -1344,6 +1400,22 @@ static int legacy_suspend(struct device return error; } +static void dpm_clear_suppliers_direct_complete(struct device *dev) +{ + struct device_link *link; + int idx; + + idx = device_links_read_lock(); + + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) { + spin_lock_irq(&link->supplier->power.lock); + link->supplier->power.direct_complete = false; + spin_unlock_irq(&link->supplier->power.lock); + } + + device_links_read_unlock(idx); +} + /** * device_suspend - Execute "suspend" callbacks for given device. * @dev: Device to handle. @@ -1360,7 +1432,7 @@ static int __device_suspend(struct devic TRACE_DEVICE(dev); TRACE_SUSPEND(0); - dpm_wait_for_children(dev, async); + dpm_wait_for_subordinate(dev, async); if (async_error) goto Complete; @@ -1456,6 +1528,7 @@ static int __device_suspend(struct devic spin_unlock_irq(&parent->power.lock); } + dpm_clear_suppliers_direct_complete(dev); } device_unlock(dev);