diff options
Diffstat (limited to 'target/linux/ipq806x/patches-4.4/170-OPP-Allow-notifiers-to-call-dev_pm_opp_get_voltage-freq-RCU-free.patch')
| -rw-r--r-- | target/linux/ipq806x/patches-4.4/170-OPP-Allow-notifiers-to-call-dev_pm_opp_get_voltage-freq-RCU-free.patch | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/target/linux/ipq806x/patches-4.4/170-OPP-Allow-notifiers-to-call-dev_pm_opp_get_voltage-freq-RCU-free.patch b/target/linux/ipq806x/patches-4.4/170-OPP-Allow-notifiers-to-call-dev_pm_opp_get_voltage-freq-RCU-free.patch new file mode 100644 index 0000000000..7be47a3509 --- /dev/null +++ b/target/linux/ipq806x/patches-4.4/170-OPP-Allow-notifiers-to-call-dev_pm_opp_get_voltage-freq-RCU-free.patch @@ -0,0 +1,114 @@ +From d330eae026b4a73e77ca0422f5cae5207d80f738 Mon Sep 17 00:00:00 2001 +From: Stephen Boyd <sboyd@codeaurora.org> +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 <k.kozlowski@samsung.com> +Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> +--- + 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); |