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From: Stephen Boyd <sboyd@codeaurora.org>
To: linux-arm-msm@vger.kernel.org
Cc: Nishanth Menon <nm@ti.com>,
	Krzysztof Kozlowski <k.kozlowski@samsung.com>,
	David Collins <collinsd@codeaurora.org>,
	linux-pm@vger.kernel.org, Viresh Kumar <viresh.kumar@linaro.org>,
	linux-kernel@vger.kernel.org, Mark Brown <broonie@kernel.org>,
	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	Andy Gross <agross@codeaurora.org>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 3/5] OPP: Allow notifiers to call dev_pm_opp_get_{voltage, freq} RCU-free
Date: Fri, 18 Sep 2015 17:52:07 -0700	[thread overview]
Message-ID: <1442623929-4507-4-git-send-email-sboyd@codeaurora.org> (raw)
In-Reply-To: <1442623929-4507-1-git-send-email-sboyd@codeaurora.org>

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.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 35b66c46dcb7..1d8c45e53245 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -146,9 +146,10 @@ static LIST_HEAD(dev_opp_list);
 /* Lock to allow exclusive modification to the device and opp lists */
 static 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");		\
@@ -236,9 +237,10 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
 	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);
+	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
@@ -268,9 +270,10 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
 	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
@@ -437,7 +440,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
 	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)) {
@@ -485,7 +488,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
 	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);
@@ -535,7 +538,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
 	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);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

WARNING: multiple messages have this Message-ID (diff)
From: Stephen Boyd <sboyd@codeaurora.org>
To: linux-arm-msm@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Nishanth Menon <nm@ti.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	Andy Gross <agross@codeaurora.org>,
	linux-pm@vger.kernel.org, Mark Brown <broonie@kernel.org>,
	David Collins <collinsd@codeaurora.org>,
	Krzysztof Kozlowski <k.kozlowski@samsung.com>
Subject: [PATCH v2 3/5] OPP: Allow notifiers to call dev_pm_opp_get_{voltage,freq} RCU-free
Date: Fri, 18 Sep 2015 17:52:07 -0700	[thread overview]
Message-ID: <1442623929-4507-4-git-send-email-sboyd@codeaurora.org> (raw)
In-Reply-To: <1442623929-4507-1-git-send-email-sboyd@codeaurora.org>

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.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 35b66c46dcb7..1d8c45e53245 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -146,9 +146,10 @@ static LIST_HEAD(dev_opp_list);
 /* Lock to allow exclusive modification to the device and opp lists */
 static 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");		\
@@ -236,9 +237,10 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
 	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);
+	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
@@ -268,9 +270,10 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
 	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
@@ -437,7 +440,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
 	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)) {
@@ -485,7 +488,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
 	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);
@@ -535,7 +538,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
 	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);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


WARNING: multiple messages have this Message-ID (diff)
From: sboyd@codeaurora.org (Stephen Boyd)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 3/5] OPP: Allow notifiers to call dev_pm_opp_get_{voltage, freq} RCU-free
Date: Fri, 18 Sep 2015 17:52:07 -0700	[thread overview]
Message-ID: <1442623929-4507-4-git-send-email-sboyd@codeaurora.org> (raw)
In-Reply-To: <1442623929-4507-1-git-send-email-sboyd@codeaurora.org>

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.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 35b66c46dcb7..1d8c45e53245 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -146,9 +146,10 @@ static LIST_HEAD(dev_opp_list);
 /* Lock to allow exclusive modification to the device and opp lists */
 static 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");		\
@@ -236,9 +237,10 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
 	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);
+	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
@@ -268,9 +270,10 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
 	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
@@ -437,7 +440,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
 	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)) {
@@ -485,7 +488,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
 	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);
@@ -535,7 +538,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
 	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);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

  parent reply	other threads:[~2015-09-19  0:52 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-19  0:52 [PATCH v2 0/5] Support CPR on MSM8916 Stephen Boyd
2015-09-19  0:52 ` Stephen Boyd
2015-09-19  0:52 ` [PATCH v2 1/5] regulator: smd: Add floor and corner operations Stephen Boyd
2015-09-19  0:52   ` Stephen Boyd
2015-09-19 16:57   ` Mark Brown
2015-09-19 16:57     ` Mark Brown
2015-09-19 16:57     ` Mark Brown
2015-09-22 16:39     ` Stephen Boyd
2015-09-22 16:39       ` Stephen Boyd
2015-09-19  0:52 ` [PATCH v2 2/5] PM / OPP: Support adjusting OPP voltages at runtime Stephen Boyd
2015-09-19  0:52   ` Stephen Boyd
2015-09-22 16:50   ` Viresh Kumar
2015-09-22 16:50     ` Viresh Kumar
2015-09-22 16:50     ` Viresh Kumar
2015-09-22 17:46     ` Stephen Boyd
2015-09-22 17:46       ` Stephen Boyd
2015-09-19  0:52 ` Stephen Boyd [this message]
2015-09-19  0:52   ` [PATCH v2 3/5] OPP: Allow notifiers to call dev_pm_opp_get_{voltage, freq} RCU-free Stephen Boyd
2015-09-19  0:52   ` [PATCH v2 3/5] OPP: Allow notifiers to call dev_pm_opp_get_{voltage,freq} RCU-free Stephen Boyd
2015-09-22 17:10   ` Viresh Kumar
2015-09-22 17:10     ` Viresh Kumar
2015-09-19  0:52 ` [PATCH v2 4/5] cpufreq-dt: Handle OPP voltage adjust events Stephen Boyd
2015-09-19  0:52   ` Stephen Boyd
2015-09-22 17:36   ` Viresh Kumar
2015-09-22 17:36     ` Viresh Kumar
2015-09-19  0:52 ` [PATCH v2 5/5] power: avs: Add support for CPR (Core Power Reduction) Stephen Boyd
2015-09-19  0:52   ` Stephen Boyd
2015-09-19 13:46 ` [PATCH v2 0/5] Support CPR on MSM8916 Mark Brown
2015-09-19 13:46   ` Mark Brown
2015-09-25 22:03 ` Rafael J. Wysocki
2015-09-25 22:03   ` Rafael J. Wysocki
2015-09-28 18:48   ` Stephen Boyd
2015-09-28 18:48     ` Stephen Boyd

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