| Message ID | 20141216005048.GA3802@dtor-ws (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On 16 December 2014 at 06:20, Dmitry Torokhov <dtor@chromium.org> wrote: > dev_pm_opp_get_opp_count() must be called with RCU lock held. > > Signed-off-by: Dmitry Torokhov <dtor@chromium.org> > --- > > Not tested at all... > > drivers/cpufreq/imx6q-cpufreq.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c > index 380a90d..851d4fd 100644 > --- a/drivers/cpufreq/imx6q-cpufreq.c > +++ b/drivers/cpufreq/imx6q-cpufreq.c > @@ -200,7 +200,9 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev) > * Just, incase the platform did not supply the OPP > * table, it will try to get it. > */ > + rcu_read_lock(); > num = dev_pm_opp_get_opp_count(cpu_dev); > + rcu_read_unlock(); > if (num < 0) { > ret = of_init_opp_table(cpu_dev); > if (ret < 0) { > @@ -211,7 +213,9 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev) > /* Because we have added the OPPs here, we must free them */ > free_opp = true; > > + rcu_read_lock(); > num = dev_pm_opp_get_opp_count(cpu_dev); > + rcu_read_unlock(); > if (num < 0) { > ret = num; > dev_err(cpu_dev, "no OPP table is found: %d\n", ret); This one looks fine for sure but I was wondering for the users which just need to call opp-count from under the locks, what about something like: dev_pm_opp_get_opp_count_locked() ? -- viresh -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Dec 15, 2014 at 9:33 PM, Viresh Kumar <viresh.kumar@linaro.org> wrote: > On 16 December 2014 at 06:20, Dmitry Torokhov <dtor@chromium.org> wrote: >> dev_pm_opp_get_opp_count() must be called with RCU lock held. >> >> Signed-off-by: Dmitry Torokhov <dtor@chromium.org> >> --- >> >> Not tested at all... >> >> drivers/cpufreq/imx6q-cpufreq.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c >> index 380a90d..851d4fd 100644 >> --- a/drivers/cpufreq/imx6q-cpufreq.c >> +++ b/drivers/cpufreq/imx6q-cpufreq.c >> @@ -200,7 +200,9 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev) >> * Just, incase the platform did not supply the OPP >> * table, it will try to get it. >> */ >> + rcu_read_lock(); >> num = dev_pm_opp_get_opp_count(cpu_dev); >> + rcu_read_unlock(); >> if (num < 0) { >> ret = of_init_opp_table(cpu_dev); >> if (ret < 0) { >> @@ -211,7 +213,9 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev) >> /* Because we have added the OPPs here, we must free them */ >> free_opp = true; >> >> + rcu_read_lock(); >> num = dev_pm_opp_get_opp_count(cpu_dev); >> + rcu_read_unlock(); >> if (num < 0) { >> ret = num; >> dev_err(cpu_dev, "no OPP table is found: %d\n", ret); > > This one looks fine for sure but I was wondering for the users which just > need to call opp-count from under the locks, what about something like: > > dev_pm_opp_get_opp_count_locked() ? Yeah, for the majority of callers taking the lock won't hurt as they call it in their init code. Thanks, Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c index 380a90d..851d4fd 100644 --- a/drivers/cpufreq/imx6q-cpufreq.c +++ b/drivers/cpufreq/imx6q-cpufreq.c @@ -200,7 +200,9 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev) * Just, incase the platform did not supply the OPP * table, it will try to get it. */ + rcu_read_lock(); num = dev_pm_opp_get_opp_count(cpu_dev); + rcu_read_unlock(); if (num < 0) { ret = of_init_opp_table(cpu_dev); if (ret < 0) { @@ -211,7 +213,9 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev) /* Because we have added the OPPs here, we must free them */ free_opp = true; + rcu_read_lock(); num = dev_pm_opp_get_opp_count(cpu_dev); + rcu_read_unlock(); if (num < 0) { ret = num; dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
dev_pm_opp_get_opp_count() must be called with RCU lock held. Signed-off-by: Dmitry Torokhov <dtor@chromium.org> --- Not tested at all... drivers/cpufreq/imx6q-cpufreq.c | 4 ++++ 1 file changed, 4 insertions(+)