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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);
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