From: Rafael J. Wysocki Date: Wed, 16 Jul 2025 19:31:23 +0000 (+0200) Subject: PM: sleep: Rearrange suspend/resume error handling in the core X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dbd4bccd96626563d1d811bc121484cd45f964a1;p=thirdparty%2Flinux.git PM: sleep: Rearrange suspend/resume error handling in the core Notice that device_suspend_noirq(), device_suspend_late() and device_suspend() all set async_error on errors, so they don't really need to return a value. Accordingly, make them all void and use async_error in their callers instead of their return values. Moreover, since async_error is updated concurrently without locking during asynchronous suspend and resume processing, use READ_ONCE() and WRITE_ONCE() for accessing it in those places to ensure that all of the accesses will be carried out as expected. Signed-off-by: Rafael J. Wysocki Reviewed-by: Saravana Kannan Link: https://patch.msgid.link/6198088.lOV4Wx5bFT@rjwysocki.net --- diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 5d9b3dc9011dc..8aa06d59a2eef 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -767,7 +767,7 @@ Out: TRACE_RESUME(error); if (error) { - async_error = error; + WRITE_ONCE(async_error, error); dpm_save_failed_dev(dev_name(dev)); pm_dev_err(dev, state, async ? " async noirq" : " noirq", error); } @@ -824,7 +824,7 @@ static void dpm_noirq_resume_devices(pm_message_t state) mutex_unlock(&dpm_list_mtx); async_synchronize_full(); dpm_show_time(starttime, state, 0, "noirq"); - if (async_error) + if (READ_ONCE(async_error)) dpm_save_failed_step(SUSPEND_RESUME_NOIRQ); trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, false); @@ -910,7 +910,7 @@ Out: complete_all(&dev->power.completion); if (error) { - async_error = error; + WRITE_ONCE(async_error, error); dpm_save_failed_dev(dev_name(dev)); pm_dev_err(dev, state, async ? " async early" : " early", error); } @@ -971,7 +971,7 @@ void dpm_resume_early(pm_message_t state) mutex_unlock(&dpm_list_mtx); async_synchronize_full(); dpm_show_time(starttime, state, 0, "early"); - if (async_error) + if (READ_ONCE(async_error)) dpm_save_failed_step(SUSPEND_RESUME_EARLY); trace_suspend_resume(TPS("dpm_resume_early"), state.event, false); @@ -1086,7 +1086,7 @@ static void device_resume(struct device *dev, pm_message_t state, bool async) TRACE_RESUME(error); if (error) { - async_error = error; + WRITE_ONCE(async_error, error); dpm_save_failed_dev(dev_name(dev)); pm_dev_err(dev, state, async ? " async" : "", error); } @@ -1150,7 +1150,7 @@ void dpm_resume(pm_message_t state) mutex_unlock(&dpm_list_mtx); async_synchronize_full(); dpm_show_time(starttime, state, 0, NULL); - if (async_error) + if (READ_ONCE(async_error)) dpm_save_failed_step(SUSPEND_RESUME); cpufreq_resume(); @@ -1387,7 +1387,7 @@ static void async_suspend_noirq(void *data, async_cookie_t cookie); * The driver of @dev will not receive interrupts while this function is being * executed. */ -static int device_suspend_noirq(struct device *dev, pm_message_t state, bool async) +static void device_suspend_noirq(struct device *dev, pm_message_t state, bool async) { pm_callback_t callback = NULL; const char *info = NULL; @@ -1398,7 +1398,7 @@ static int device_suspend_noirq(struct device *dev, pm_message_t state, bool asy dpm_wait_for_subordinate(dev, async); - if (async_error) + if (READ_ONCE(async_error)) goto Complete; if (dev->power.syscore || dev->power.direct_complete) @@ -1431,7 +1431,7 @@ static int device_suspend_noirq(struct device *dev, pm_message_t state, bool asy Run: error = dpm_run_callback(callback, dev, state, info); if (error) { - async_error = error; + WRITE_ONCE(async_error, error); dpm_save_failed_dev(dev_name(dev)); pm_dev_err(dev, state, async ? " async noirq" : " noirq", error); goto Complete; @@ -1457,12 +1457,10 @@ Complete: complete_all(&dev->power.completion); TRACE_SUSPEND(error); - if (error || async_error) - return error; + if (error || READ_ONCE(async_error)) + return; dpm_async_suspend_superior(dev, async_suspend_noirq); - - return 0; } static void async_suspend_noirq(void *data, async_cookie_t cookie) @@ -1477,7 +1475,7 @@ static int dpm_noirq_suspend_devices(pm_message_t state) { ktime_t starttime = ktime_get(); struct device *dev; - int error = 0; + int error; trace_suspend_resume(TPS("dpm_suspend_noirq"), state.event, true); @@ -1508,13 +1506,13 @@ static int dpm_noirq_suspend_devices(pm_message_t state) mutex_unlock(&dpm_list_mtx); - error = device_suspend_noirq(dev, state, false); + device_suspend_noirq(dev, state, false); put_device(dev); mutex_lock(&dpm_list_mtx); - if (error || async_error) { + if (READ_ONCE(async_error)) { dpm_async_suspend_complete_all(&dpm_late_early_list); /* * Move all devices to the target list to resume them @@ -1528,9 +1526,8 @@ static int dpm_noirq_suspend_devices(pm_message_t state) mutex_unlock(&dpm_list_mtx); async_synchronize_full(); - if (!error) - error = async_error; + error = READ_ONCE(async_error); if (error) dpm_save_failed_step(SUSPEND_SUSPEND_NOIRQ); @@ -1585,7 +1582,7 @@ static void async_suspend_late(void *data, async_cookie_t cookie); * * Runtime PM is disabled for @dev while this function is being executed. */ -static int device_suspend_late(struct device *dev, pm_message_t state, bool async) +static void device_suspend_late(struct device *dev, pm_message_t state, bool async) { pm_callback_t callback = NULL; const char *info = NULL; @@ -1602,11 +1599,11 @@ static int device_suspend_late(struct device *dev, pm_message_t state, bool asyn dpm_wait_for_subordinate(dev, async); - if (async_error) + if (READ_ONCE(async_error)) goto Complete; if (pm_wakeup_pending()) { - async_error = -EBUSY; + WRITE_ONCE(async_error, -EBUSY); goto Complete; } @@ -1640,7 +1637,7 @@ static int device_suspend_late(struct device *dev, pm_message_t state, bool asyn Run: error = dpm_run_callback(callback, dev, state, info); if (error) { - async_error = error; + WRITE_ONCE(async_error, error); dpm_save_failed_dev(dev_name(dev)); pm_dev_err(dev, state, async ? " async late" : " late", error); goto Complete; @@ -1654,12 +1651,10 @@ Complete: TRACE_SUSPEND(error); complete_all(&dev->power.completion); - if (error || async_error) - return error; + if (error || READ_ONCE(async_error)) + return; dpm_async_suspend_superior(dev, async_suspend_late); - - return 0; } static void async_suspend_late(void *data, async_cookie_t cookie) @@ -1678,7 +1673,7 @@ int dpm_suspend_late(pm_message_t state) { ktime_t starttime = ktime_get(); struct device *dev; - int error = 0; + int error; trace_suspend_resume(TPS("dpm_suspend_late"), state.event, true); @@ -1711,13 +1706,13 @@ int dpm_suspend_late(pm_message_t state) mutex_unlock(&dpm_list_mtx); - error = device_suspend_late(dev, state, false); + device_suspend_late(dev, state, false); put_device(dev); mutex_lock(&dpm_list_mtx); - if (error || async_error) { + if (READ_ONCE(async_error)) { dpm_async_suspend_complete_all(&dpm_suspended_list); /* * Move all devices to the target list to resume them @@ -1731,9 +1726,8 @@ int dpm_suspend_late(pm_message_t state) mutex_unlock(&dpm_list_mtx); async_synchronize_full(); - if (!error) - error = async_error; + error = READ_ONCE(async_error); if (error) { dpm_save_failed_step(SUSPEND_SUSPEND_LATE); dpm_resume_early(resume_event(state)); @@ -1822,7 +1816,7 @@ static void async_suspend(void *data, async_cookie_t cookie); * @state: PM transition of the system being carried out. * @async: If true, the device is being suspended asynchronously. */ -static int device_suspend(struct device *dev, pm_message_t state, bool async) +static void device_suspend(struct device *dev, pm_message_t state, bool async) { pm_callback_t callback = NULL; const char *info = NULL; @@ -1834,7 +1828,7 @@ static int device_suspend(struct device *dev, pm_message_t state, bool async) dpm_wait_for_subordinate(dev, async); - if (async_error) { + if (READ_ONCE(async_error)) { dev->power.direct_complete = false; goto Complete; } @@ -1854,7 +1848,7 @@ static int device_suspend(struct device *dev, pm_message_t state, bool async) if (pm_wakeup_pending()) { dev->power.direct_complete = false; - async_error = -EBUSY; + WRITE_ONCE(async_error, -EBUSY); goto Complete; } @@ -1938,7 +1932,7 @@ static int device_suspend(struct device *dev, pm_message_t state, bool async) Complete: if (error) { - async_error = error; + WRITE_ONCE(async_error, error); dpm_save_failed_dev(dev_name(dev)); pm_dev_err(dev, state, async ? " async" : "", error); } @@ -1946,12 +1940,10 @@ static int device_suspend(struct device *dev, pm_message_t state, bool async) complete_all(&dev->power.completion); TRACE_SUSPEND(error); - if (error || async_error) - return error; + if (error || READ_ONCE(async_error)) + return; dpm_async_suspend_superior(dev, async_suspend); - - return 0; } static void async_suspend(void *data, async_cookie_t cookie) @@ -1970,7 +1962,7 @@ int dpm_suspend(pm_message_t state) { ktime_t starttime = ktime_get(); struct device *dev; - int error = 0; + int error; trace_suspend_resume(TPS("dpm_suspend"), state.event, true); might_sleep(); @@ -2005,13 +1997,13 @@ int dpm_suspend(pm_message_t state) mutex_unlock(&dpm_list_mtx); - error = device_suspend(dev, state, false); + device_suspend(dev, state, false); put_device(dev); mutex_lock(&dpm_list_mtx); - if (error || async_error) { + if (READ_ONCE(async_error)) { dpm_async_suspend_complete_all(&dpm_prepared_list); /* * Move all devices to the target list to resume them @@ -2025,9 +2017,8 @@ int dpm_suspend(pm_message_t state) mutex_unlock(&dpm_list_mtx); async_synchronize_full(); - if (!error) - error = async_error; + error = READ_ONCE(async_error); if (error) dpm_save_failed_step(SUSPEND_SUSPEND);