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authorDmitry Torokhov <dmitry.torokhov@gmail.com>2013-02-23 13:11:14 -0800
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2013-02-25 23:02:42 -0800
commitd6b0c58048d2c8c6f4955c37f670125b2792cd14 (patch)
treea22d3680ebcaca7681f647ac0ab050ef1f51c968 /drivers/base
parent7241443f67bb352183bcfd7e3b807b87f2777b5d (diff)
downloadop-kernel-dev-d6b0c58048d2c8c6f4955c37f670125b2792cd14.zip
op-kernel-dev-d6b0c58048d2c8c6f4955c37f670125b2792cd14.tar.gz
devres: allow adding custom actions to the stack
Sometimes drivers need to execute one-off actions in their error handling or device teardown paths. An example would be toggling a GPIO line to reset the controlled device into predefined state. To allow performing such actions when using managed resources let's allow adding them to stack/group of devres resources. Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/devres.c74
1 files changed, 74 insertions, 0 deletions
diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index 8731979..724957a 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -671,6 +671,80 @@ int devres_release_group(struct device *dev, void *id)
EXPORT_SYMBOL_GPL(devres_release_group);
/*
+ * Custom devres actions allow inserting a simple function call
+ * into the teadown sequence.
+ */
+
+struct action_devres {
+ void *data;
+ void (*action)(void *);
+};
+
+static int devm_action_match(struct device *dev, void *res, void *p)
+{
+ struct action_devres *devres = res;
+ struct action_devres *target = p;
+
+ return devres->action == target->action &&
+ devres->data == target->data;
+}
+
+static void devm_action_release(struct device *dev, void *res)
+{
+ struct action_devres *devres = res;
+
+ devres->action(devres->data);
+}
+
+/**
+ * devm_add_action() - add a custom action to list of managed resources
+ * @dev: Device that owns the action
+ * @action: Function that should be called
+ * @data: Pointer to data passed to @action implementation
+ *
+ * This adds a custom action to the list of managed resources so that
+ * it gets executed as part of standard resource unwinding.
+ */
+int devm_add_action(struct device *dev, void (*action)(void *), void *data)
+{
+ struct action_devres *devres;
+
+ devres = devres_alloc(devm_action_release,
+ sizeof(struct action_devres), GFP_KERNEL);
+ if (!devres)
+ return -ENOMEM;
+
+ devres->data = data;
+ devres->action = action;
+
+ devres_add(dev, devres);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(devm_add_action);
+
+/**
+ * devm_remove_action() - removes previously added custom action
+ * @dev: Device that owns the action
+ * @action: Function implementing the action
+ * @data: Pointer to data passed to @action implementation
+ *
+ * Removes instance of @action previously added by devm_add_action().
+ * Both action and data should match one of the existing entries.
+ */
+void devm_remove_action(struct device *dev, void (*action)(void *), void *data)
+{
+ struct action_devres devres = {
+ .data = data,
+ .action = action,
+ };
+
+ WARN_ON(devres_destroy(dev, devm_action_release, devm_action_match,
+ &devres));
+
+}
+EXPORT_SYMBOL_GPL(devm_remove_action);
+
+/*
* Managed kzalloc/kfree
*/
static void devm_kzalloc_release(struct device *dev, void *res)
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