Messages in this thread Patch in this message | | | Date | Mon, 11 Nov 2019 17:01:17 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH] opp: Reinitialize the list_kref before adding the static OPPs again |
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On 11-11-19, 13:51, Viresh Kumar wrote: > On 30-10-19, 07:33, Stephen Boyd wrote: > > I agree a simple refcount_t makes more sense here instead of using a > > kref. That would be clearer. > > I was using kref as I wanted to call the cleanup routine when kref > reaches 0. A refcount_t will have the same problem as the warning in > this came from refcount mechanism only (which is used by kref). You > can't increment a refcount_t if it is zero :) > > Any other suggestions other than local counting ?
i.e. something like this, untested.
--- drivers/opp/core.c | 26 ++++++++------------------ drivers/opp/of.c | 14 +++++--------- drivers/opp/opp.h | 6 ++---- 3 files changed, 15 insertions(+), 31 deletions(-)
diff --git a/drivers/opp/core.c b/drivers/opp/core.c index 467b2348a289..ea1d89177511 100644 --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -988,7 +988,6 @@ static struct opp_table *_allocate_opp_table(struct device *dev, int index) BLOCKING_INIT_NOTIFIER_HEAD(&opp_table->head); INIT_LIST_HEAD(&opp_table->opp_list); kref_init(&opp_table->kref); - kref_init(&opp_table->list_kref); /* Secure the device table modification */ list_add(&opp_table->node, &opp_tables); @@ -1076,27 +1075,18 @@ static void _opp_remove_all_static(struct opp_table *opp_table) { struct dev_pm_opp *opp, *tmp; + mutex_lock(&opp_table->lock); + + if (!opp_table->parsed_static_opps || --opp_table->parsed_static_opps) + goto unlock; + list_for_each_entry_safe(opp, tmp, &opp_table->opp_list, node) { if (!opp->dynamic) dev_pm_opp_put(opp); } - opp_table->parsed_static_opps = false; -} - -static void _opp_table_list_kref_release(struct kref *kref) -{ - struct opp_table *opp_table = container_of(kref, struct opp_table, - list_kref); - - _opp_remove_all_static(opp_table); - mutex_unlock(&opp_table_lock); -} - -void _put_opp_list_kref(struct opp_table *opp_table) -{ - kref_put_mutex(&opp_table->list_kref, _opp_table_list_kref_release, - &opp_table_lock); +unlock: + mutex_unlock(&opp_table->lock); } void dev_pm_opp_put_opp_table(struct opp_table *opp_table) @@ -2276,7 +2266,7 @@ void _dev_pm_opp_find_and_remove_table(struct device *dev) return; } - _put_opp_list_kref(opp_table); + _opp_remove_all_static(opp_table); /* Drop reference taken by _find_opp_table() */ dev_pm_opp_put_opp_table(opp_table); diff --git a/drivers/opp/of.c b/drivers/opp/of.c index 1cbb58240b80..2c433e9f9223 100644 --- a/drivers/opp/of.c +++ b/drivers/opp/of.c @@ -658,17 +658,15 @@ static int _of_add_opp_table_v2(struct device *dev, struct opp_table *opp_table) struct dev_pm_opp *opp; /* OPP table is already initialized for the device */ + mutex_lock(&opp_table->lock); if (opp_table->parsed_static_opps) { - kref_get(&opp_table->list_kref); + opp_table->parsed_static_opps++; + mutex_unlock(&opp_table->lock); return 0; } - /* - * Re-initialize list_kref every time we add static OPPs to the OPP - * table as the reference count may be 0 after the last tie static OPPs - * were removed. - */ - kref_init(&opp_table->list_kref); + opp_table->parsed_static_opps = 1; + mutex_unlock(&opp_table->lock); /* We have opp-table node now, iterate over it and add OPPs */ for_each_available_child_of_node(opp_table->np, np) { @@ -701,8 +699,6 @@ static int _of_add_opp_table_v2(struct device *dev, struct opp_table *opp_table) if (pstate_count) opp_table->genpd_performance_state = true; - opp_table->parsed_static_opps = true; - return 0; } diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h index 51ad942d1b6b..4e69b855a6a0 100644 --- a/drivers/opp/opp.h +++ b/drivers/opp/opp.h @@ -127,11 +127,10 @@ enum opp_table_access { * @dev_list: list of devices that share these OPPs * @opp_list: table of opps * @kref: for reference count of the table. - * @list_kref: for reference count of the OPP list. * @lock: mutex protecting the opp_list and dev_list. * @np: struct device_node pointer for opp's DT node. * @clock_latency_ns_max: Max clock latency in nanoseconds. - * @parsed_static_opps: True if OPPs are initialized from DT. + * @parsed_static_opps: Count of devices for which OPPs are initialized from DT. * @shared_opp: OPP is shared between multiple devices. * @suspend_opp: Pointer to OPP to be used during device suspend. * @genpd_virt_dev_lock: Mutex protecting the genpd virtual device pointers. @@ -167,7 +166,6 @@ struct opp_table { struct list_head dev_list; struct list_head opp_list; struct kref kref; - struct kref list_kref; struct mutex lock; struct device_node *np; @@ -176,7 +174,7 @@ struct opp_table { /* For backward compatibility with v1 bindings */ unsigned int voltage_tolerance_v1; - bool parsed_static_opps; + unsigned int parsed_static_opps; enum opp_table_access shared_opp; struct dev_pm_opp *suspend_opp;
-- viresh
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