| Message ID | 1442623929-4507-4-git-send-email-sboyd@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 18-09-15, 17:52, Stephen Boyd wrote: > 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); Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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);
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(-)