From da997b22c40473b7db60bde6ea188d35565d10c8 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Thu, 8 Feb 2018 08:30:10 -0800 Subject: PM / wakeirq: Add wakeup name to dedicated wake irqs This makes it easy to grep :wakeup /proc/interrupts. Suggested-by: Jeffy Chen Signed-off-by: Tony Lindgren Reviewed-by: Andy Shevchenko Signed-off-by: Rafael J. Wysocki --- drivers/base/power/power.h | 1 + drivers/base/power/wakeirq.c | 13 +++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h index 21244c53e377..86e67e70b509 100644 --- a/drivers/base/power/power.h +++ b/drivers/base/power/power.h @@ -31,6 +31,7 @@ struct wake_irq { struct device *dev; unsigned int status; int irq; + const char *name; }; extern void dev_pm_arm_wake_irq(struct wake_irq *wirq); diff --git a/drivers/base/power/wakeirq.c b/drivers/base/power/wakeirq.c index 6637fc319269..b8fa5c0f2d13 100644 --- a/drivers/base/power/wakeirq.c +++ b/drivers/base/power/wakeirq.c @@ -112,6 +112,7 @@ void dev_pm_clear_wake_irq(struct device *dev) free_irq(wirq->irq, wirq); wirq->status &= ~WAKE_IRQ_DEDICATED_MASK; } + kfree(wirq->name); kfree(wirq); } EXPORT_SYMBOL_GPL(dev_pm_clear_wake_irq); @@ -184,6 +185,12 @@ int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq) if (!wirq) return -ENOMEM; + wirq->name = kasprintf(GFP_KERNEL, "%s:wakeup", dev_name(dev)); + if (!wirq->name) { + err = -ENOMEM; + goto err_free; + } + wirq->dev = dev; wirq->irq = irq; irq_set_status_flags(irq, IRQ_NOAUTOEN); @@ -196,9 +203,9 @@ int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq) * so we use a threaded irq. */ err = request_threaded_irq(irq, NULL, handle_threaded_wake_irq, - IRQF_ONESHOT, dev_name(dev), wirq); + IRQF_ONESHOT, wirq->name, wirq); if (err) - goto err_free; + goto err_free_name; err = dev_pm_attach_wake_irq(dev, irq, wirq); if (err) @@ -210,6 +217,8 @@ int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq) err_free_irq: free_irq(irq, wirq); +err_free_name: + kfree(wirq->name); err_free: kfree(wirq); -- cgit v1.2.3 From ead18c23c263374ed098a7d955b29b4a466d4573 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Sat, 10 Feb 2018 19:27:12 +0100 Subject: driver core: Introduce device links reference counting If device_link_add() is invoked multiple times with the same supplier and consumer combo, it will create the link on first addition and return a pointer to the already existing link on all subsequent additions. The semantics for device_link_del() are quite different, it deletes the link unconditionally, so multiple invocations are not allowed. In other words, this snippet ... struct device *dev1, *dev2; struct device_link *link1, *link2; link1 = device_link_add(dev1, dev2, 0); link2 = device_link_add(dev1, dev2, 0); device_link_del(link1); device_link_del(link2); ... causes the following crash: WARNING: CPU: 4 PID: 2686 at drivers/base/power/runtime.c:1611 pm_runtime_drop_link+0x40/0x50 [...] list_del corruption, 0000000039b800a4->prev is LIST_POISON2 (00000000ecf79852) kernel BUG at lib/list_debug.c:50! The issue isn't as arbitrary as it may seem: Imagine a device link which is added in both the supplier's and the consumer's ->probe hook. The two drivers can't just call device_link_del() in their ->remove hook without coordination. Fix by counting multiple additions and dropping the device link only when the last addition is unwound. Signed-off-by: Lukas Wunner [ rjw: Subject ] Signed-off-by: Rafael J. Wysocki --- drivers/base/core.c | 25 +++++++++++++++++-------- include/linux/device.h | 2 ++ 2 files changed, 19 insertions(+), 8 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/core.c b/drivers/base/core.c index 5847364f25d9..b610816eb887 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -196,8 +196,10 @@ struct device_link *device_link_add(struct device *consumer, } list_for_each_entry(link, &supplier->links.consumers, s_node) - if (link->consumer == consumer) + if (link->consumer == consumer) { + kref_get(&link->kref); goto out; + } link = kzalloc(sizeof(*link), GFP_KERNEL); if (!link) @@ -222,6 +224,7 @@ struct device_link *device_link_add(struct device *consumer, link->consumer = consumer; INIT_LIST_HEAD(&link->c_node); link->flags = flags; + kref_init(&link->kref); /* Determine the initial link state. */ if (flags & DL_FLAG_STATELESS) { @@ -292,8 +295,10 @@ static void __device_link_free_srcu(struct rcu_head *rhead) device_link_free(container_of(rhead, struct device_link, rcu_head)); } -static void __device_link_del(struct device_link *link) +static void __device_link_del(struct kref *kref) { + struct device_link *link = container_of(kref, struct device_link, kref); + dev_info(link->consumer, "Dropping the link to %s\n", dev_name(link->supplier)); @@ -305,8 +310,10 @@ static void __device_link_del(struct device_link *link) call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu); } #else /* !CONFIG_SRCU */ -static void __device_link_del(struct device_link *link) +static void __device_link_del(struct kref *kref) { + struct device_link *link = container_of(kref, struct device_link, kref); + dev_info(link->consumer, "Dropping the link to %s\n", dev_name(link->supplier)); @@ -324,13 +331,15 @@ static void __device_link_del(struct device_link *link) * @link: Device link to delete. * * The caller must ensure proper synchronization of this function with runtime - * PM. + * PM. If the link was added multiple times, it needs to be deleted as often. + * Care is required for hotplugged devices: Their links are purged on removal + * and calling device_link_del() is then no longer allowed. */ void device_link_del(struct device_link *link) { device_links_write_lock(); device_pm_lock(); - __device_link_del(link); + kref_put(&link->kref, __device_link_del); device_pm_unlock(); device_links_write_unlock(); } @@ -444,7 +453,7 @@ static void __device_links_no_driver(struct device *dev) continue; if (link->flags & DL_FLAG_AUTOREMOVE) - __device_link_del(link); + kref_put(&link->kref, __device_link_del); else if (link->status != DL_STATE_SUPPLIER_UNBIND) WRITE_ONCE(link->status, DL_STATE_AVAILABLE); } @@ -597,13 +606,13 @@ static void device_links_purge(struct device *dev) list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) { WARN_ON(link->status == DL_STATE_ACTIVE); - __device_link_del(link); + __device_link_del(&link->kref); } list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) { WARN_ON(link->status != DL_STATE_DORMANT && link->status != DL_STATE_NONE); - __device_link_del(link); + __device_link_del(&link->kref); } device_links_write_unlock(); diff --git a/include/linux/device.h b/include/linux/device.h index b093405ed525..abf952c82c6d 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -769,6 +769,7 @@ enum device_link_state { * @status: The state of the link (with respect to the presence of drivers). * @flags: Link flags. * @rpm_active: Whether or not the consumer device is runtime-PM-active. + * @kref: Count repeated addition of the same link. * @rcu_head: An RCU head to use for deferred execution of SRCU callbacks. */ struct device_link { @@ -779,6 +780,7 @@ struct device_link { enum device_link_state status; u32 flags; bool rpm_active; + struct kref kref; #ifdef CONFIG_SRCU struct rcu_head rcu_head; #endif -- cgit v1.2.3