[RFC PATCH 1/7] drivers: base: Add resource managed version of delayed work init

[Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>]

A few drivers which need a delayed work-queue must cancel work at exit.
Some of those implement remove solely for this purpose. Help drivers
to avoid unnecessary remove and error-branch implementation by adding
managed verision of delayed work initialization

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
---
 drivers/base/devres.c  | 33 +++++++++++++++++++++++++++++++++
 include/linux/device.h |  5 +++++
 2 files changed, 38 insertions(+)

diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index fb9d5289a620..2879595bb5a4 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -1231,3 +1231,36 @@ void devm_free_percpu(struct device *dev, void __percpu *pdata)
 			       (void *)pdata));
 }
 EXPORT_SYMBOL_GPL(devm_free_percpu);
+
+static void dev_delayed_work_drop(struct device *dev, void *res)
+{
+	cancel_delayed_work_sync(*(struct delayed_work **)res);
+}
+
+/**
+ * devm_delayed_work_autocancel - Resource-managed work allocation
+ * @dev: Device which lifetime work is bound to
+ * @pdata: work to be cancelled when device exits
+ *
+ * Initialize work which is automatically cancelled when device exits.
+ * A few drivers need delayed work which must be cancelled before driver
+ * is unload to avoid accessing removed resources.
+ * devm_delayed_work_autocancel() can be used to omit the explicit
+ * cancelleation when driver is unload.
+ */
+int devm_delayed_work_autocancel(struct device *dev, struct delayed_work *w,
+				 void (*worker)(struct work_struct *work))
+{
+	struct delayed_work **ptr;
+
+	ptr = devres_alloc(dev_delayed_work_drop, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	INIT_DELAYED_WORK(w, worker);
+	*ptr = w;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_delayed_work_autocancel);
diff --git a/include/linux/device.h b/include/linux/device.h
index 1779f90eeb4c..192456198de7 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -27,6 +27,7 @@
 #include <linux/uidgid.h>
 #include <linux/gfp.h>
 #include <linux/overflow.h>
+#include <linux/workqueue.h>
 #include <linux/device/bus.h>
 #include <linux/device/class.h>
 #include <linux/device/driver.h>
@@ -249,6 +250,10 @@ void __iomem *devm_of_iomap(struct device *dev,
 			    struct device_node *node, int index,
 			    resource_size_t *size);
 
+/* delayed work which is cancelled when driver exits */
+int devm_delayed_work_autocancel(struct device *dev, struct delayed_work *w,
+				 void (*worker)(struct work_struct *work));
+
 /* allows to add/remove a custom action to devres stack */
 int devm_add_action(struct device *dev, void (*action)(void *), void *data);
 void devm_remove_action(struct device *dev, void (*action)(void *), void *data);
-- 
2.25.4


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]