From d330eae026b4a73e77ca0422f5cae5207d80f738 Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Mon, 1 Jun 2015 18:47:57 -0700 Subject: OPP: Allow notifiers to call dev_pm_opp_get_{voltage, freq} RCU-free We pass the dev_pm_opp structure to OPP notifiers but the users of the notifier need to surround calls to dev_pm_opp_get_*() with RCU read locks to avoid lockdep warnings. The notifier is already called with the dev_opp's srcu lock held, so it should be safe to assume the devm_pm_opp structure is already protected inside the notifier. Update the lockdep check for this. Cc: Krzysztof Kozlowski Signed-off-by: Stephen Boyd --- drivers/base/power/opp/core.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) --- a/drivers/base/power/opp/core.c +++ b/drivers/base/power/opp/core.c @@ -31,9 +31,10 @@ static LIST_HEAD(dev_opp_list); /* Lock to allow exclusive modification to the device and opp lists */ DEFINE_MUTEX(dev_opp_list_lock); -#define opp_rcu_lockdep_assert() \ +#define opp_rcu_lockdep_assert(s) \ do { \ RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \ + !(s && srcu_read_lock_held(s)) && \ !lockdep_is_held(&dev_opp_list_lock), \ "Missing rcu_read_lock() or " \ "dev_opp_list_lock protection"); \ @@ -91,7 +92,7 @@ struct device_opp *_find_device_opp(stru { struct device_opp *dev_opp; - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); if (IS_ERR_OR_NULL(dev)) { pr_err("%s: Invalid parameters\n", __func__); @@ -125,10 +126,11 @@ unsigned long dev_pm_opp_get_voltage(str struct dev_pm_opp *tmp_opp; unsigned long v = 0; - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(&opp->dev_opp->srcu_head.srcu); - tmp_opp = rcu_dereference(opp); - if (IS_ERR_OR_NULL(tmp_opp)) + tmp_opp = srcu_dereference_check(opp, &opp->dev_opp->srcu_head.srcu, + rcu_read_lock_held()); + if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) pr_err("%s: Invalid parameters\n", __func__); else v = tmp_opp->u_volt; @@ -157,9 +159,10 @@ unsigned long dev_pm_opp_get_freq(struct struct dev_pm_opp *tmp_opp; unsigned long f = 0; - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(&opp->dev_opp->srcu_head.srcu); - tmp_opp = rcu_dereference(opp); + tmp_opp = srcu_dereference_check(opp, &opp->dev_opp->srcu_head.srcu, + rcu_read_lock_held()); if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) pr_err("%s: Invalid parameters\n", __func__); else @@ -191,7 +194,7 @@ bool dev_pm_opp_is_turbo(struct dev_pm_o { struct dev_pm_opp *tmp_opp; - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(&opp->dev_opp->srcu_head.srcu); tmp_opp = rcu_dereference(opp); if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) { @@ -246,7 +249,7 @@ struct dev_pm_opp *dev_pm_opp_get_suspen { struct device_opp *dev_opp; - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); dev_opp = _find_device_opp(dev); if (IS_ERR(dev_opp) || !dev_opp->suspend_opp || @@ -326,7 +329,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ struct device_opp *dev_opp; struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); dev_opp = _find_device_opp(dev); if (IS_ERR(dev_opp)) { @@ -374,7 +377,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ struct device_opp *dev_opp; struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); if (!dev || !freq) { dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); @@ -424,7 +427,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ struct device_opp *dev_opp; struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); if (!dev || !freq) { dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);