Messages in this thread Patch in this message | | | From | Marek Szyprowski <> | Subject | [PATCH v7 1/2] drivers: base: add support for registering notifier about deferred probe | Date | Wed, 13 Apr 2016 11:35:59 +0200 |
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This patch adds code which allow other subsystems get a notification when deferred probe has been triggered. This way one can retry some actions, which earlier failed with -EPROBE_DEFER error code.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- drivers/base/dd.c | 31 +++++++++++++++++++++++++++++++ include/linux/device.h | 3 +++ 2 files changed, 34 insertions(+)
diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 16688f50729c..208466eb83fb 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -19,6 +19,7 @@ #include <linux/device.h> #include <linux/delay.h> +#include <linux/notifier.h> #include <linux/module.h> #include <linux/kthread.h> #include <linux/wait.h> @@ -53,6 +54,7 @@ static LIST_HEAD(deferred_probe_pending_list); static LIST_HEAD(deferred_probe_active_list); static struct workqueue_struct *deferred_wq; static atomic_t deferred_trigger_count = ATOMIC_INIT(0); +static BLOCKING_NOTIFIER_HEAD(deferred_notifier_head); /* * In some cases, like suspend to RAM or hibernation, It might be reasonable @@ -113,6 +115,9 @@ static void deferred_probe_work_func(struct work_struct *work) put_device(dev); } mutex_unlock(&deferred_probe_mutex); + + /* Notify any listeners about triggering deferred probe */ + blocking_notifier_call_chain(&deferred_notifier_head, 0, NULL); } static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func); @@ -224,6 +229,32 @@ static int deferred_probe_initcall(void) late_initcall(deferred_probe_initcall); /** + * deferred_probe_register_notifier - Register a notifier for deferred probe + * @nb: notifier block to signal + * + * This function allows caller to get a notification when deferred probe has + * been triggered. This lets it to retry some actions, which earlier failed + * with -EPROBE_DEFER error code. + */ +int deferred_probe_register_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&deferred_notifier_head, nb); +} +EXPORT_SYMBOL_GPL(deferred_probe_register_notifier); + +/** + * deferred_probe_unregister_notifier - Unregister a notifier + * @nb: notifier block to signal + * + * Unregister a previously registered deferred probe notifier. + */ +int deferred_probe_unregister_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&deferred_notifier_head, nb); +} +EXPORT_SYMBOL_GPL(deferred_probe_unregister_notifier); + +/** * device_is_bound() - Check if device is bound to a driver * @dev: device to check * diff --git a/include/linux/device.h b/include/linux/device.h index 002c59728dbe..c6496d1db5de 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -1066,6 +1066,9 @@ extern int __must_check device_reprobe(struct device *dev); extern bool device_is_bound(struct device *dev); +extern int deferred_probe_register_notifier(struct notifier_block *nb); +extern int deferred_probe_unregister_notifier(struct notifier_block *nb); + /* * Easy functions for dynamically creating devices on the fly */ -- 1.9.2
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