Re: [PATCH 07/10] PM / OPP: Don't allocate OPP table from _opp_allocate()

On 07-12-16, 14:05, Stephen Boyd wrote:

Sorry I don't understand. After this patch it looks like dev is unused in the function because we delete the only user _add_opp_table().

Sorry, I misread your earlier comment :(

I haven't looked at the next round of patches. If the lock is still held across the notifier for OPP_EVENT_ADD then it would seem that we should get some sort of lockdep splat if the notified functions want to call back into the OPP code and that takes the same lock we held across the notifier.

Right.

Even if it would work for the other notifiers that aren't OPP_EVENT_ADD, lockdep wouldn't know that because of locking classes, hence the splat.

yes.

That's my only concern. Obviously if the locking is going away then it's just a bisection hole problem that I'm willing to ignore.

Yes it is surely going away and we wouldn't get the splat for now as well. I already confirmed that only devfreq uses OPP notifiers. I can also confirm that only two devfreq drivers (rk3399 and exynos) register the notifiers and they do that after adding the OPP table.

IOW, no one is listening to OPP_ADD event for now.

Here is the new version of the patch. I will send the complete series only after all the patches are reviewed now..

-------------------------8<-------------------------

Subject: [PATCH] PM / OPP: Don't allocate OPP table from _opp_allocate()

There is no point in trying to find/allocate the table for every OPP that is added for a device. It would be far more efficient to allocate the table only once and pass its pointer to the routines that add the OPP entry.

Locking is removed from _opp_add_static_v2() and _opp_add_v1() now as the callers call them with that lock already held.

Call to _remove_opp_table() routine is also removed from _opp_free() now, as opp_table isn't allocated from within _opp_allocate(). This is handled by the routines which created the OPP table in the first place.

Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- drivers/base/power/opp/core.c | 67 +++++++++++++++++++------------------- drivers/base/power/opp/of.c | 75 ++++++++++++++++++++++--------------------- drivers/base/power/opp/opp.h | 9 ++++-- 3 files changed, 78 insertions(+), 73 deletions(-)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c index b3a624a4af81..dde7dd099aa0 100644 --- a/drivers/base/power/opp/core.c +++ b/drivers/base/power/opp/core.c @@ -829,7 +829,7 @@ struct opp_device *_add_opp_dev(const struct device *dev, * * Return: valid opp_table pointer if success, else NULL. */ -static struct opp_table *_add_opp_table(struct device *dev) +struct opp_table *_add_opp_table(struct device *dev) { struct opp_table *opp_table; struct opp_device *opp_dev; @@ -929,10 +929,9 @@ static void _remove_opp_table(struct opp_table *opp_table) _kfree_device_rcu); }

-void _opp_free(struct dev_pm_opp *opp, struct opp_table *opp_table) +void _opp_free(struct dev_pm_opp *opp) { kfree(opp); - _remove_opp_table(opp_table); }

/** @@ -1016,16 +1015,10 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq) } EXPORT_SYMBOL_GPL(dev_pm_opp_remove);

-struct dev_pm_opp *_opp_allocate(struct device *dev, - struct opp_table **opp_table) +struct dev_pm_opp *_opp_allocate(struct opp_table *table) { struct dev_pm_opp *opp; int count, supply_size; - struct opp_table *table; - - table = _add_opp_table(dev); - if (!table) - return NULL;

/* Allocate space for at least one supply */ count = table->regulator_count ? table->regulator_count : 1; @@ -1033,17 +1026,13 @@ struct dev_pm_opp *_opp_allocate(struct device *dev,

/* allocate new OPP node and supplies structures */ opp = kzalloc(sizeof(*opp) + supply_size, GFP_KERNEL); - if (!opp) { - kfree(table); + if (!opp) return NULL; - }

/* Put the supplies at the end of the OPP structure as an empty array */ opp->supplies = (struct dev_pm_opp_supply *)(opp + 1); INIT_LIST_HEAD(&opp->node);

- *opp_table = table; - return opp; }

@@ -1133,6 +1122,7 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,

/** * _opp_add_v1() - Allocate a OPP based on v1 bindings. + * @opp_table: OPP table * @dev: device for which we do this operation * @freq: Frequency in Hz for this OPP * @u_volt: Voltage in uVolts for this OPP @@ -1158,22 +1148,18 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, * Duplicate OPPs (both freq and volt are same) and !opp->available * -ENOMEM Memory allocation failure */ -int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt, - bool dynamic) +int _opp_add_v1(struct opp_table *opp_table, struct device *dev, + unsigned long freq, long u_volt, bool dynamic) { - struct opp_table *opp_table; struct dev_pm_opp *new_opp; unsigned long tol; int ret;

- /* Hold our table modification lock here */ - mutex_lock(&opp_table_lock); + opp_rcu_lockdep_assert();

- new_opp = _opp_allocate(dev, &opp_table); - if (!new_opp) { - ret = -ENOMEM; - goto unlock; - } + new_opp = _opp_allocate(opp_table); + if (!new_opp) + return -ENOMEM;

/* populate the opp table */ new_opp->rate = freq; @@ -1192,8 +1178,6 @@ int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt, goto free_opp; }

- mutex_unlock(&opp_table_lock); - /* * Notify the changes in the availability of the operable * frequency/voltage list. @@ -1202,9 +1186,8 @@ int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt, return 0;

free_opp: - _opp_free(new_opp, opp_table); -unlock: - mutex_unlock(&opp_table_lock); + _opp_free(new_opp); + return ret; }

@@ -1722,7 +1705,25 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_register_put_opp_helper); */ int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt) { - return _opp_add_v1(dev, freq, u_volt, true); + struct opp_table *opp_table; + int ret; + + /* Hold our table modification lock here */ + mutex_lock(&opp_table_lock); + + opp_table = _add_opp_table(dev); + if (!opp_table) { + ret = -ENOMEM; + goto unlock; + } + + ret = _opp_add_v1(opp_table, dev, freq, u_volt, true); + if (ret) + _remove_opp_table(opp_table); + +unlock: + mutex_unlock(&opp_table_lock); + return ret; } EXPORT_SYMBOL_GPL(dev_pm_opp_add);

@@ -1888,8 +1889,8 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_notifier); * Free OPPs either created using static entries present in DT or even the * dynamically added entries based on remove_all param. */ -static void _dev_pm_opp_remove_table(struct opp_table *opp_table, - struct device *dev, bool remove_all) +void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev, + bool remove_all) { struct dev_pm_opp *opp, *tmp;

diff --git a/drivers/base/power/opp/of.c b/drivers/base/power/opp/of.c index 442fa46c4f5c..cdbf733ac9b1 100644 --- a/drivers/base/power/opp/of.c +++ b/drivers/base/power/opp/of.c @@ -255,6 +255,7 @@ static struct device_node *_of_get_opp_desc_node(struct device *dev)

/** * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings) + * @opp_table: OPP table * @dev: device for which we do this operation * @np: device node * @@ -276,22 +277,17 @@ static struct device_node *_of_get_opp_desc_node(struct device *dev) * -ENOMEM Memory allocation failure * -EINVAL Failed parsing the OPP node */ -static int _opp_add_static_v2(struct device *dev, struct device_node *np) +static int _opp_add_static_v2(struct opp_table *opp_table, struct device *dev, + struct device_node *np) { - struct opp_table *opp_table; struct dev_pm_opp *new_opp; u64 rate; u32 val; int ret;

- /* Hold our table modification lock here */ - mutex_lock(&opp_table_lock); - - new_opp = _opp_allocate(dev, &opp_table); - if (!new_opp) { - ret = -ENOMEM; - goto unlock; - } + new_opp = _opp_allocate(opp_table); + if (!new_opp) + return -ENOMEM;

ret = of_property_read_u64(np, "opp-hz", &rate); if (ret < 0) { @@ -347,8 +343,6 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np) if (new_opp->clock_latency_ns > opp_table->clock_latency_ns_max) opp_table->clock_latency_ns_max = new_opp->clock_latency_ns;

- mutex_unlock(&opp_table_lock); - pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu\n", __func__, new_opp->turbo, new_opp->rate, new_opp->supplies[0].u_volt, new_opp->supplies[0].u_volt_min, @@ -362,9 +356,8 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np) return 0;

free_opp: - _opp_free(new_opp, opp_table); -unlock: - mutex_unlock(&opp_table_lock); + _opp_free(new_opp); + return ret; }

@@ -382,16 +375,20 @@ static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np) /* OPPs are already managed */ if (!_add_opp_dev(dev, opp_table)) ret = -ENOMEM; - mutex_unlock(&opp_table_lock); - return ret; + goto unlock; + } + + opp_table = _add_opp_table(dev); + if (!opp_table) { + ret = -ENOMEM; + goto unlock; } - mutex_unlock(&opp_table_lock);

/* We have opp-table node now, iterate over it and add OPPs */ for_each_available_child_of_node(opp_np, np) { count++;

- ret = _opp_add_static_v2(dev, np); + ret = _opp_add_static_v2(opp_table, dev, np); if (ret) { dev_err(dev, "%s: Failed to add OPP, %d\n", __func__, ret); @@ -400,15 +397,8 @@ static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np) }

/* There should be one of more OPP defined */ - if (WARN_ON(!count)) - return -ENOENT; - - mutex_lock(&opp_table_lock); - - opp_table = _find_opp_table(dev); - if (WARN_ON(IS_ERR(opp_table))) { - ret = PTR_ERR(opp_table); - mutex_unlock(&opp_table_lock); + if (WARN_ON(!count)) { + ret = -ENOENT; goto free_table; }

@@ -418,12 +408,12 @@ static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np) else opp_table->shared_opp = OPP_TABLE_ACCESS_EXCLUSIVE;

- mutex_unlock(&opp_table_lock); - - return 0; + goto unlock;

free_table: - dev_pm_opp_of_remove_table(dev); + _dev_pm_opp_remove_table(opp_table, dev, false); +unlock: + mutex_unlock(&opp_table_lock);

return ret; } @@ -431,9 +421,10 @@ static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np) /* Initializes OPP tables based on old-deprecated bindings */ static int _of_add_opp_table_v1(struct device *dev) { + struct opp_table *opp_table; const struct property *prop; const __be32 *val; - int nr, ret; + int nr, ret = 0;

prop = of_find_property(dev->of_node, "operating-points", NULL); if (!prop) @@ -451,22 +442,32 @@ static int _of_add_opp_table_v1(struct device *dev) return -EINVAL; }

+ mutex_lock(&opp_table_lock); + + opp_table = _add_opp_table(dev); + if (!opp_table) { + ret = -ENOMEM; + goto unlock; + } + val = prop->value; while (nr) { unsigned long freq = be32_to_cpup(val++) * 1000; unsigned long volt = be32_to_cpup(val++);

- ret = _opp_add_v1(dev, freq, volt, false); + ret = _opp_add_v1(opp_table, dev, freq, volt, false); if (ret) { dev_err(dev, "%s: Failed to add OPP %ld (%d)\n", __func__, freq, ret); - dev_pm_opp_of_remove_table(dev); - return ret; + _dev_pm_opp_remove_table(opp_table, dev, false); + break; } nr -= 2; }

- return 0; +unlock: + mutex_unlock(&opp_table_lock); + return ret; }

/** diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h index c4b539a8533a..0a5eb4d1e8f7 100644 --- a/drivers/base/power/opp/opp.h +++ b/drivers/base/power/opp/opp.h @@ -191,13 +191,16 @@ struct opp_table {

/* Routines internal to opp core */ struct opp_table *_find_opp_table(struct device *dev); +struct opp_table *_add_opp_table(struct device *dev); struct opp_device *_add_opp_dev(const struct device *dev, struct opp_table *opp_table); +void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev, bool remove_all); void _dev_pm_opp_find_and_remove_table(struct device *dev, bool remove_all); -struct dev_pm_opp *_opp_allocate(struct device *dev, struct opp_table **opp_table); -void _opp_free(struct dev_pm_opp *opp, struct opp_table *opp_table); +struct dev_pm_opp *_opp_allocate(struct opp_table *opp_table); +void _opp_free(struct dev_pm_opp *opp); int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, struct opp_table *opp_table); -int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt, bool dynamic); +int _opp_add_v1(struct opp_table *opp_table, struct device *dev, unsigned long freq, long u_volt, bool dynamic); void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask, bool of); +struct opp_table *_add_opp_table(struct device *dev);

#ifdef CONFIG_OF void _of_init_opp_table(struct opp_table *opp_table, struct device *dev);