[RFC,4/6] power: supply: core: add locking around extension access

Message ID	20240606-power-supply-extensions-v1-4-b45669290bdc@weissschuh.net (mailing list archive)
State	Handled Elsewhere, archived
Headers	show Received: from todd.t-8ch.de (todd.t-8ch.de [159.69.126.157]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7BF9A1A2550; Thu, 6 Jun 2024 14:51:06 +0000 (UTC) From: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= <linux@weissschuh.net> Date: Thu, 06 Jun 2024 16:50:58 +0200 Subject: [PATCH RFC 4/6] power: supply: core: add locking around extension access Precedence: bulk MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Message-Id: <20240606-power-supply-extensions-v1-4-b45669290bdc@weissschuh.net> References: <20240606-power-supply-extensions-v1-0-b45669290bdc@weissschuh.net> In-Reply-To: <20240606-power-supply-extensions-v1-0-b45669290bdc@weissschuh.net> To: Sebastian Reichel <sre@kernel.org>, Jeremy Soller <jeremy@system76.com>, System76 Product Development <productdev@system76.com>, Hans de Goede <hdegoede@redhat.com>, =?utf-8?q?Ilpo_J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com> Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org, =?utf-8?q?Thomas_Wei=C3=9Fschuh?= <linux@weissschuh.net>
Series	power: supply: extension API \| expand [RFC,0/6] power: supply: extension API [RFC,1/6] power: supply: sysfs: use power_supply_property_is_writeable() [RFC,2/6] power: supply: core: avoid iterating properties directly [RFC,3/6] power: supply: core: implement extension API [RFC,4/6] power: supply: core: add locking around extension access [RFC,5/6] power: supply: test-power: implement a power supply extension [RFC,6/6] platform/x86: system76: Use power_supply extension API

diff --git a/drivers/power/supply/power_supply.h b/drivers/power/supply/power_supply.h index 7f9e139064cc..b469a9719045 100644 --- a/drivers/power/supply/power_supply.h +++ b/drivers/power/supply/power_supply.h @@ -13,10 +13,14 @@ struct device; struct device_type; struct power_supply; -bool power_supply_has_property(const struct power_supply *psy, +bool power_supply_has_property(struct power_supply *psy, enum power_supply_property psp); +bool power_supply_has_property_nolock(struct power_supply *psy, + enum power_supply_property psp); bool power_supply_ext_has_property(const struct power_supply_ext *psy_ext, enum power_supply_property psp); +int power_supply_property_is_writeable_nolock(struct power_supply *psy, + enum power_supply_property psp); #ifdef CONFIG_SYSFS diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c index b32bbca9a848..ded9748be550 100644 --- a/drivers/power/supply/power_supply_core.c +++ b/drivers/power/supply/power_supply_core.c @@ -1218,14 +1218,26 @@ bool power_supply_ext_has_property(const struct power_supply_ext *psy_ext, return found; } -bool power_supply_has_property(const struct power_supply *psy, - enum power_supply_property psp) +bool power_supply_has_property_nolock(struct power_supply *psy, + enum power_supply_property psp) { + lockdep_assert_held(&psy->ext_lock); + if (power_supply_ext_has_property(psy->ext, psp)) return true; return psy_desc_has_property(psy->desc, psp); } +bool power_supply_has_property(struct power_supply *psy, + enum power_supply_property psp) +{ + scoped_guard(rwsem_read, &psy->ext_lock) { + if (power_supply_ext_has_property(psy->ext, psp)) + return true; + } + return psy_desc_has_property(psy->desc, psp); +} + int power_supply_get_property(struct power_supply *psy, enum power_supply_property psp, union power_supply_propval *val) @@ -1236,9 +1248,12 @@ int power_supply_get_property(struct power_supply *psy, return -ENODEV; } - if (power_supply_ext_has_property(psy->ext, psp)) - return psy->ext->get_property(psy, psp, val); - else if (psy_desc_has_property(psy->desc, psp)) + scoped_guard(rwsem_read, &psy->ext_lock) { + if (power_supply_ext_has_property(psy->ext, psp)) + return psy->ext->get_property(psy, psp, val); + } + + if (psy_desc_has_property(psy->desc, psp)) return psy->desc->get_property(psy, psp, val); else if (power_supply_battery_info_has_prop(psy->battery_info, psp)) return power_supply_battery_info_get_prop(psy->battery_info, psp, val); @@ -1254,11 +1269,13 @@ int power_supply_set_property(struct power_supply *psy, if (atomic_read(&psy->use_cnt) <= 0) return -ENODEV; - if (power_supply_ext_has_property(psy->ext, psp)) { - if (psy->ext->set_property) - return psy->ext->set_property(psy, psp, val); - else - return -ENODEV; + scoped_guard(rwsem_read, &psy->ext_lock) { + if (power_supply_ext_has_property(psy->ext, psp)) { + if (psy->ext->set_property) + return psy->ext->set_property(psy, psp, val); + else + return -ENODEV; + } } if (!psy->desc->set_property) @@ -1274,6 +1291,28 @@ int power_supply_property_is_writeable(struct power_supply *psy, if (atomic_read(&psy->use_cnt) <= 0) return -ENODEV; + scoped_guard(rwsem_read, &psy->ext_lock) { + if (power_supply_ext_has_property(psy->ext, psp)) { + if (psy->ext->property_is_writeable) + return psy->ext->property_is_writeable(psy, psp); + else + return -ENODEV; + } + } + + if (!psy->desc->property_is_writeable) + return -ENODEV; + + return psy->desc->property_is_writeable(psy, psp); +} +EXPORT_SYMBOL_GPL(power_supply_property_is_writeable); + +int power_supply_property_is_writeable_nolock(struct power_supply *psy, + enum power_supply_property psp) +{ + if (atomic_read(&psy->use_cnt) <= 0) + return -ENODEV; + if (power_supply_ext_has_property(psy->ext, psp)) { if (psy->ext->property_is_writeable) return psy->ext->property_is_writeable(psy, psp); @@ -1286,7 +1325,6 @@ int power_supply_property_is_writeable(struct power_supply *psy, return psy->desc->property_is_writeable(psy, psp); } -EXPORT_SYMBOL_GPL(power_supply_property_is_writeable); void power_supply_external_power_changed(struct power_supply *psy) { @@ -1315,6 +1353,8 @@ static int power_supply_update_groups(struct power_supply *psy) int power_supply_register_extension(struct power_supply *psy, const struct power_supply_ext *ext) { + guard(rwsem_write)(&psy->ext_lock); + if (psy->ext) return -EEXIST; @@ -1325,6 +1365,8 @@ EXPORT_SYMBOL_GPL(power_supply_register_extension); void power_supply_unregister_extension(struct power_supply *psy, const struct power_supply_ext *ext) { + guard(rwsem_write)(&psy->ext_lock); + if (psy->ext != ext) dev_warn(&psy->dev, "Trying to unregister invalid extension"); @@ -1492,6 +1534,7 @@ __power_supply_register(struct device *parent, } spin_lock_init(&psy->changed_lock); + init_rwsem(&psy->ext_lock); rc = device_add(dev); if (rc) goto device_add_failed; diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c index 3487f161e9bf..d47804cbb500 100644 --- a/drivers/power/supply/power_supply_sysfs.c +++ b/drivers/power/supply/power_supply_sysfs.c @@ -378,8 +378,8 @@ static umode_t power_supply_attr_is_visible(struct kobject *kobj, if (attrno == POWER_SUPPLY_PROP_TYPE) return mode; - if (power_supply_has_property(psy, attrno)) { - if (power_supply_property_is_writeable(psy, attrno) > 0) + if (power_supply_has_property_nolock(psy, attrno)) { + if (power_supply_property_is_writeable_nolock(psy, attrno) > 0) mode |= S_IWUSR; return mode; } @@ -458,7 +458,7 @@ static int add_prop_uevent(const struct device *dev, struct kobj_uevent_env *env int power_supply_uevent(const struct device *dev, struct kobj_uevent_env *env) { - const struct power_supply *psy = dev_get_drvdata(dev); + struct power_supply *psy = dev_get_drvdata(dev); const enum power_supply_property *battery_props = power_supply_battery_info_properties; unsigned long psy_drv_properties[POWER_SUPPLY_ATTR_CNT / @@ -490,13 +490,15 @@ int power_supply_uevent(const struct device *dev, struct kobj_uevent_env *env) if (ret) goto out; - if (psy->ext) { - for (j = 0; j < psy->ext->num_properties; j++) { - set_bit(psy->ext->properties[j], psy_drv_properties); - ret = add_prop_uevent(dev, env, psy->ext->properties[j], - prop_buf); - if (ret) - goto out; + scoped_guard(rwsem_read, &psy->ext_lock) { + if (psy->ext) { + for (j = 0; j < psy->ext->num_properties; j++) { + set_bit(psy->ext->properties[j], psy_drv_properties); + ret = add_prop_uevent(dev, env, psy->ext->properties[j], + prop_buf); + if (ret) + goto out; + } } } diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h index 0c1e23081d2a..6bba7e6ab161 100644 --- a/include/linux/power_supply.h +++ b/include/linux/power_supply.h @@ -15,6 +15,7 @@ #include <linux/device.h> #include <linux/workqueue.h> #include <linux/leds.h> +#include <linux/rwsem.h> #include <linux/spinlock.h> #include <linux/notifier.h> @@ -306,6 +307,7 @@ struct power_supply { size_t num_supplies; struct device_node *of_node; + struct rw_semaphore ext_lock; const struct power_supply_ext *ext; /* Driver private data */

[RFC,4/6] power: supply: core: add locking around extension access

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Patch