From d5dcce0c414fcbfe4c2037b66ac69ea5f9b3f75c Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Thu, 22 Oct 2020 21:40:59 +0300 Subject: device property: Keep secondary firmware node secondary by type Behind primary and secondary we understand the type of the nodes which might define their ordering. However, if primary node gone, we can't maintain the ordering by definition of the linked list. Thus, by ordering secondary node becomes first in the list. But in this case the meaning of it is still secondary (or auxiliary). The type of the node is maintained by the secondary pointer in it: secondary pointer Meaning NULL or valid primary node ERR_PTR(-ENODEV) secondary node So, if by some reason we do the following sequence of calls set_primary_fwnode(dev, NULL); set_primary_fwnode(dev, primary); we should preserve secondary node. This concept is supported by the description of set_primary_fwnode() along with implementation of set_secondary_fwnode(). Hence, fix the commit c15e1bdda436 to follow this as well. Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()") Cc: Ferry Toth Signed-off-by: Andy Shevchenko Reviewed-by: Heikki Krogerus Tested-by: Ferry Toth Cc: 5.9+ # 5.9+ Signed-off-by: Rafael J. Wysocki --- drivers/base/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/base/core.c') diff --git a/drivers/base/core.c b/drivers/base/core.c index c852f16c111b..41feab679fa1 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -4278,7 +4278,7 @@ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode) } else { if (fwnode_is_primary(fn)) { dev->fwnode = fn->secondary; - fn->secondary = NULL; + fn->secondary = ERR_PTR(-ENODEV); } else { dev->fwnode = NULL; } -- cgit From 99aed9227073fb34ce2880cbc7063e04185a65e1 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Thu, 22 Oct 2020 21:41:00 +0300 Subject: device property: Don't clear secondary pointer for shared primary firmware node It appears that firmware nodes can be shared between devices. In such case when a (child) device is about to be deleted, its firmware node may be shared and ACPI_COMPANION_SET(..., NULL) call for it breaks the secondary link of the shared primary firmware node. In order to prevent that, check, if the device has a parent and parent's firmware node is shared with its child, and avoid crashing the link. Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()") Reported-by: Ferry Toth Signed-off-by: Andy Shevchenko Reviewed-by: Heikki Krogerus Tested-by: Ferry Toth Cc: 5.9+ # 5.9+ Signed-off-by: Rafael J. Wysocki --- drivers/base/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/base/core.c') diff --git a/drivers/base/core.c b/drivers/base/core.c index 41feab679fa1..78114ddac755 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -4264,6 +4264,7 @@ static inline bool fwnode_is_primary(struct fwnode_handle *fwnode) */ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode) { + struct device *parent = dev->parent; struct fwnode_handle *fn = dev->fwnode; if (fwnode) { @@ -4278,7 +4279,8 @@ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode) } else { if (fwnode_is_primary(fn)) { dev->fwnode = fn->secondary; - fn->secondary = ERR_PTR(-ENODEV); + if (!(parent && fn == parent->fwnode)) + fn->secondary = ERR_PTR(-ENODEV); } else { dev->fwnode = NULL; } -- cgit From e0e398e204634db8fb71bd89cf2f6e3e5bd09b51 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 21 Oct 2020 21:12:15 +0200 Subject: PM: runtime: Drop runtime PM references to supplier on link removal While removing a device link, drop the supplier device's runtime PM usage counter as many times as needed to drop all of the runtime PM references to it from the consumer in addition to dropping the consumer's link count. Fixes: baa8809f6097 ("PM / runtime: Optimize the use of device links") Signed-off-by: Rafael J. Wysocki Cc: 5.1+ # 5.1+ Tested-by: Xiang Chen Reviewed-by: Greg Kroah-Hartman --- drivers/base/core.c | 6 ++---- drivers/base/power/runtime.c | 21 ++++++++++++++++++++- include/linux/pm_runtime.h | 4 ++-- 3 files changed, 24 insertions(+), 7 deletions(-) (limited to 'drivers/base/core.c') diff --git a/drivers/base/core.c b/drivers/base/core.c index 78114ddac755..d661ada1518f 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -773,8 +773,7 @@ static void __device_link_del(struct kref *kref) dev_dbg(link->consumer, "Dropping the link to %s\n", dev_name(link->supplier)); - if (link->flags & DL_FLAG_PM_RUNTIME) - pm_runtime_drop_link(link->consumer); + pm_runtime_drop_link(link); list_del_rcu(&link->s_node); list_del_rcu(&link->c_node); @@ -788,8 +787,7 @@ static void __device_link_del(struct kref *kref) dev_info(link->consumer, "Dropping the link to %s\n", dev_name(link->supplier)); - if (link->flags & DL_FLAG_PM_RUNTIME) - pm_runtime_drop_link(link->consumer); + pm_runtime_drop_link(link); list_del(&link->s_node); list_del(&link->c_node); diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 6f605f7820bb..6919f7fc226b 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -1729,7 +1729,7 @@ void pm_runtime_new_link(struct device *dev) spin_unlock_irq(&dev->power.lock); } -void pm_runtime_drop_link(struct device *dev) +static void pm_runtime_drop_link_count(struct device *dev) { spin_lock_irq(&dev->power.lock); WARN_ON(dev->power.links_count == 0); @@ -1737,6 +1737,25 @@ void pm_runtime_drop_link(struct device *dev) spin_unlock_irq(&dev->power.lock); } +/** + * pm_runtime_drop_link - Prepare for device link removal. + * @link: Device link going away. + * + * Drop the link count of the consumer end of @link and decrement the supplier + * device's runtime PM usage counter as many times as needed to drop all of the + * PM runtime reference to it from the consumer. + */ +void pm_runtime_drop_link(struct device_link *link) +{ + if (!(link->flags & DL_FLAG_PM_RUNTIME)) + return; + + pm_runtime_drop_link_count(link->consumer); + + while (refcount_dec_not_one(&link->rpm_active)) + pm_runtime_put(link->supplier); +} + static bool pm_runtime_need_not_resume(struct device *dev) { return atomic_read(&dev->power.usage_count) <= 1 && diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index 18b02dcc168e..eadc1fdebce6 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -58,7 +58,7 @@ extern void pm_runtime_clean_up_links(struct device *dev); extern void pm_runtime_get_suppliers(struct device *dev); extern void pm_runtime_put_suppliers(struct device *dev); extern void pm_runtime_new_link(struct device *dev); -extern void pm_runtime_drop_link(struct device *dev); +extern void pm_runtime_drop_link(struct device_link *link); /** * pm_runtime_get_if_in_use - Conditionally bump up runtime PM usage counter. @@ -280,7 +280,7 @@ static inline void pm_runtime_clean_up_links(struct device *dev) {} static inline void pm_runtime_get_suppliers(struct device *dev) {} static inline void pm_runtime_put_suppliers(struct device *dev) {} static inline void pm_runtime_new_link(struct device *dev) {} -static inline void pm_runtime_drop_link(struct device *dev) {} +static inline void pm_runtime_drop_link(struct device_link *link) {} #endif /* !CONFIG_PM */ -- cgit