From: Rafael J. Wysocki <rafael.j.wyso...@intel.com> 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_cos...@mail.gmail.com/ Fixes: 21d5c57b3726 ("PM / runtime: Use device links") Reported-by: elaine.zhang <zhangq...@rock-chips.com> Diagnosed-by: Ulf Hansson <ulf.hans...@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com> --- This is different from the previously posted tentative patch, please retest. --- drivers/base/power/runtime.c | 61 +++++++++++++++++++++++++------------------ 1 file changed, 36 insertions(+), 25 deletions(-) Index: linux-pm/drivers/base/power/runtime.c =================================================================== --- linux-pm.orig/drivers/base/power/runtime.c +++ linux-pm/drivers/base/power/runtime.c @@ -325,22 +325,21 @@ static void rpm_put_suppliers(struct 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; + int retval, idx; + bool get, 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 +354,36 @@ static int __rpm_callback(int (*cb)(stru 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); }
