linux-kernel - [PATCH v2 1/5] devm-helpers: Add resource managed version of work init

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Date:   Tue, 18 May 2021 15:31:57 +0300
From:   Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
To:     Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
        Matti Vaittinen <mazziesaccount@...il.com>
Cc:     hanwoo Choi <cw00.choi@...sung.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/5] 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@...rohmeurope.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
---
 include/linux/devm-helpers.h | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/include/linux/devm-helpers.h b/include/linux/devm-helpers.h
index f40f77717a24..74891802200d 100644
--- 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
-- 
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 =] 

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