From 4a17bbfcf72c94b37079e39a7c1e1e8653f7fe92 Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Fri, 18 Sep 2015 17:52:07 -0700 Subject: [PATCH 50/69] 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 Acked-by: Viresh Kumar Signed-off-by: Georgi Djakov --- drivers/base/power/opp/core.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) --- a/drivers/base/power/opp/core.c +++ b/drivers/base/power/opp/core.c @@ -32,9 +32,10 @@ LIST_HEAD(opp_tables); /* Lock to allow exclusive modification to the device and opp lists */ DEFINE_MUTEX(opp_table_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(&opp_table_lock), \ "Missing rcu_read_lock() or " \ "opp_table_lock protection"); \ @@ -72,7 +73,7 @@ struct opp_table *_find_opp_table(struct { struct opp_table *opp_table; - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); if (IS_ERR_OR_NULL(dev)) { pr_err("%s: Invalid parameters\n", __func__); @@ -106,7 +107,7 @@ 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(NULL); tmp_opp = rcu_dereference(opp); if (IS_ERR_OR_NULL(tmp_opp)) @@ -138,7 +139,7 @@ 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(NULL); tmp_opp = rcu_dereference(opp); if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) @@ -172,7 +173,7 @@ bool dev_pm_opp_is_turbo(struct dev_pm_o { struct dev_pm_opp *tmp_opp; - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); tmp_opp = rcu_dereference(opp); if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) { @@ -300,7 +301,7 @@ struct dev_pm_opp *dev_pm_opp_get_suspen { struct opp_table *opp_table; - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); opp_table = _find_opp_table(dev); if (IS_ERR(opp_table) || !opp_table->suspend_opp || @@ -380,7 +381,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ struct opp_table *opp_table; struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); opp_table = _find_opp_table(dev); if (IS_ERR(opp_table)) { @@ -444,7 +445,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ { struct opp_table *opp_table; - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); if (!dev || !freq) { dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); @@ -486,7 +487,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ struct opp_table *opp_table; 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);