devm-helpers: Add resource managed version of work init

A few drivers which need a work-queue must cancel work at driver detach.
Some of those implement remove() solely for this purpose. Help drivers to
avoid unnecessary remove and error-branch implementation by adding managed
verision of work initialization. This will also help drivers to avoid
mixing manual and devm based unwinding when other resources are handled by
devm.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/94ff4175e7f2ff134ed2fa7d6e7641005cc9784b.1623146580.git.matti.vaittinen@fi.rohmeurope.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/include/linux/devm-helpers.h b/include/linux/devm-helpers.h
index f40f777..7489180 100644 (file)
--- a/include/linux/devm-helpers.h
+++ b/include/linux/devm-helpers.h
@@ -51,4 +51,29 @@ static inline int devm_delayed_work_autocancel(struct device *dev,
        return devm_add_action(dev, devm_delayed_work_drop, w);
 }
 
+static inline void devm_work_drop(void *res)
+{
+       cancel_work_sync(res);
+}
+
+/**
+ * devm_work_autocancel - Resource-managed work allocation
+ * @dev:       Device which lifetime work is bound to
+ * @w:         Work to be added (and automatically cancelled)
+ * @worker:    Worker function
+ *
+ * Initialize work which is automatically cancelled when driver is detached.
+ * A few drivers need to queue work which must be cancelled before driver
+ * is detached to avoid accessing removed resources.
+ * devm_work_autocancel() can be used to omit the explicit
+ * cancelleation when driver is detached.
+ */
+static inline int devm_work_autocancel(struct device *dev,
+                                      struct work_struct *w,
+                                      work_func_t worker)
+{
+       INIT_WORK(w, worker);
+       return devm_add_action(dev, devm_work_drop, w);
+}
+
 #endif