diff mbox series

[v5,01/18] of: Add cleanup.h based auto release via __free(device_node) markings.

Message ID 20240216203215.40870-2-brgl@bgdev.pl (mailing list archive)
State New, archived
Headers show
Series power: sequencing: implement the subsystem and add first users | expand

Checks

Context Check Description
tedd_an/pre-ci_am success Success

Commit Message

Bartosz Golaszewski Feb. 16, 2024, 8:31 p.m. UTC 
From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

The recent addition of scope based cleanup support to the kernel
provides a convenient tool to reduce the chances of leaking reference
counts where of_node_put() should have been called in an error path.

This enables
	struct device_node *child __free(device_node) = NULL;

	for_each_child_of_node(np, child) {
		if (test)
			return test;
	}

with no need for a manual call of of_node_put().
A following patch will reduce the scope of the child variable to the
for loop, to avoid an issues with ordering of autocleanup, and make it
obvious when this assigned a non NULL value.

In this simple example the gains are small but there are some very
complex error handling cases buried in these loops that will be
greatly simplified by enabling early returns with out the need
for this manual of_node_put() call.

Note that there are coccinelle checks in
scripts/coccinelle/iterators/for_each_child.cocci to detect a failure
to call of_node_put(). This new approach does not cause false positives.
Longer term we may want to add scripting to check this new approach is
done correctly with no double of_node_put() calls being introduced due
to the auto cleanup. It may also be useful to script finding places
this new approach is useful.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 include/linux/of.h | 2 ++
 1 file changed, 2 insertions(+)

Comments

bluez.test.bot@gmail.com Feb. 16, 2024, 8:36 p.m. UTC | #1 
This is an automated email and please do not reply to this email.

Dear Submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
While preparing the CI tests, the patches you submitted couldn't be applied to the current HEAD of the repository.

----- Output -----

error: patch failed: arch/arm64/boot/dts/qcom/sm8650-qrd.dts:1139
error: arch/arm64/boot/dts/qcom/sm8650-qrd.dts: patch does not apply
hint: Use 'git am --show-current-patch' to see the failed patch

Please resolve the issue and submit the patches again.


---
Regards,
Linux Bluetooth
diff mbox series

Patch

diff --git a/include/linux/of.h b/include/linux/of.h
index 331e05918f11..8df240214db1 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -13,6 +13,7 @@ 
  */
 #include <linux/types.h>
 #include <linux/bitops.h>
+#include <linux/cleanup.h>
 #include <linux/errno.h>
 #include <linux/kobject.h>
 #include <linux/mod_devicetable.h>
@@ -134,6 +135,7 @@  static inline struct device_node *of_node_get(struct device_node *node)
 }
 static inline void of_node_put(struct device_node *node) { }
 #endif /* !CONFIG_OF_DYNAMIC */
+DEFINE_FREE(device_node, struct device_node *, if (_T) of_node_put(_T))
 
 /* Pointer for first entry in chain of all nodes. */
 extern struct device_node *of_root;