From 44cc89f764646b2f1f2ea5d1a08b230131707851 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 25 Feb 2021 19:23:27 +0100 Subject: PM: runtime: Update device status before letting suppliers suspend Because the PM-runtime status of the device is not updated in __rpm_callback(), attempts to suspend the suppliers of the given device triggered by rpm_put_suppliers() called by it may fail. Fix this by making __rpm_callback() update the device's status to RPM_SUSPENDED before calling rpm_put_suppliers() if the current status of the device is RPM_SUSPENDING and the callback just invoked by it has returned 0 (success). While at it, modify the code in __rpm_callback() to always check the device's PM-runtime status under its PM lock. Link: https://lore.kernel.org/linux-pm/CAPDyKFqm06KDw_p8WXsM4dijDbho4bb6T4k50UqqvR1_COsp8g@mail.gmail.com/ Fixes: 21d5c57b3726 ("PM / runtime: Use device links") Reported-by: Elaine Zhang Diagnosed-by: Ulf Hansson Signed-off-by: Rafael J. Wysocki Tested-by: Elaine Zhang Reviewed-by: Ulf Hansson Cc: 4.10+ # 4.10+ Signed-off-by: Rafael J. Wysocki --- drivers/base/power/runtime.c | 62 ++++++++++++++++++++++++++------------------ 1 file changed, 37 insertions(+), 25 deletions(-) diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index a46a7e30881b..18b82427d0cb 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) { - int retval, idx; bool use_links = dev->power.links_count > 0; + bool get = false; + int retval, idx; + bool put; 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. - * - * 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) { + /* Resume suppliers if necessary. */ + if (get) { idx = device_links_read_lock(); retval = rpm_get_suppliers(dev); @@ -355,24 +355,36 @@ static int __rpm_callback(int (*cb)(struct device *), struct device *dev) if (dev->power.irq_safe) { spin_lock(&dev->power.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(); + return retval; + } - fail: - rpm_put_suppliers(dev); + spin_lock_irq(&dev->power.lock); - device_links_read_unlock(idx); - } + 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(); + +fail: + rpm_put_suppliers(dev); + + device_links_read_unlock(idx); spin_lock_irq(&dev->power.lock); } -- cgit v1.2.3 From f3c141057976120148ca32d9d030a2256a5ffb7b Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Wed, 24 Feb 2021 19:30:21 +0100 Subject: powercap/drivers/dtpm: Fix root node initialization The root node is not set to NULL when the dtpm root node is removed. Consequently, it is not possible to create a new root as it is already set. Set the root node to NULL when the last node is removed. Signed-off-by: Daniel Lezcano Signed-off-by: Rafael J. Wysocki --- drivers/powercap/dtpm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/powercap/dtpm.c b/drivers/powercap/dtpm.c index 5a51cd34a7e8..c2185ec5f887 100644 --- a/drivers/powercap/dtpm.c +++ b/drivers/powercap/dtpm.c @@ -207,6 +207,9 @@ int dtpm_release_zone(struct powercap_zone *pcz) if (dtpm->ops) dtpm->ops->release(dtpm); + if (root == dtpm) + root = NULL; + kfree(dtpm); return 0; -- cgit v1.2.3 From 9e2be308f023a741a0d4024bef508ef88dfb3a43 Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Wed, 24 Feb 2021 19:30:22 +0100 Subject: powercap/drivers/dtpm: Add the experimental label to the option description The DTPM framework will evolve in the next cycles. Let's add a temporary EXPERIMENTAL tag to the option so users will be aware the API may change over time. Signed-off-by: Daniel Lezcano Signed-off-by: Rafael J. Wysocki --- drivers/powercap/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/powercap/Kconfig b/drivers/powercap/Kconfig index 20b4325c6161..8242e8c5ed77 100644 --- a/drivers/powercap/Kconfig +++ b/drivers/powercap/Kconfig @@ -45,7 +45,7 @@ config IDLE_INJECT on a per CPU basis. config DTPM - bool "Power capping for Dynamic Thermal Power Management" + bool "Power capping for Dynamic Thermal Power Management (EXPERIMENTAL)" help This enables support for the power capping for the dynamic thermal power management userspace engine. -- cgit v1.2.3