From 5ab699810d46011ad2195c5916f3cbc684bfe3ee Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Thu, 16 Nov 2006 15:42:07 +0100 Subject: [PATCH] driver core: Introduce device_find_child(). Introduce device_find_child() to match device_for_each_child(). Signed-off-by: Cornelia Huck Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 33 +++++++++++++++++++++++++++++++++ include/linux/device.h | 2 ++ 2 files changed, 35 insertions(+) diff --git a/drivers/base/core.c b/drivers/base/core.c index 5d11bbdfbd2f..a29e68545462 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -750,12 +750,45 @@ int device_for_each_child(struct device * parent, void * data, return error; } +/** + * device_find_child - device iterator for locating a particular device. + * @parent: parent struct device + * @data: Data to pass to match function + * @match: Callback function to check device + * + * This is similar to the device_for_each_child() function above, but it + * returns a reference to a device that is 'found' for later use, as + * determined by the @match callback. + * + * The callback should return 0 if the device doesn't match and non-zero + * if it does. If the callback returns non-zero and a reference to the + * current device can be obtained, this function will return to the caller + * and not iterate over any more devices. + */ +struct device * device_find_child(struct device *parent, void *data, + int (*match)(struct device *, void *)) +{ + struct klist_iter i; + struct device *child; + + if (!parent) + return NULL; + + klist_iter_init(&parent->klist_children, &i); + while ((child = next_device(&i))) + if (match(child, data) && get_device(child)) + break; + klist_iter_exit(&i); + return child; +} + int __init devices_init(void) { return subsystem_register(&devices_subsys); } EXPORT_SYMBOL_GPL(device_for_each_child); +EXPORT_SYMBOL_GPL(device_find_child); EXPORT_SYMBOL_GPL(device_initialize); EXPORT_SYMBOL_GPL(device_add); diff --git a/include/linux/device.h b/include/linux/device.h index 2d9dc358c027..0a0370c74181 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -421,6 +421,8 @@ extern int __must_check device_add(struct device * dev); extern void device_del(struct device * dev); extern int device_for_each_child(struct device *, void *, int (*fn)(struct device *, void *)); +extern struct device *device_find_child(struct device *, void *data, + int (*match)(struct device *, void *)); extern int device_rename(struct device *dev, char *new_name); /* -- 2.20.1