From patchwork Sun Jan 14 16:53:55 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Cameron X-Patchwork-Id: 762833 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3F22E5231; Sun, 14 Jan 2024 16:54:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JYyzReS4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 724F2C43390; Sun, 14 Jan 2024 16:54:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1705251257; bh=3W1qHEpkEEvNPT0uRw4qBpEp9CwZhHXPWsBb4ES3aiw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JYyzReS4uoTuzJYfBvbtzCM9fU52/WE5RmYMrtt96OEQHyPlvG6lbnEaL3vIJ3iyd wBdAFAj/hxtTBb5cCqDxsn7b6Dxk7hJNnWLFe9RUPOPDG22m6LvQ0wtmwAhTUN9Rla ZSDmiXRC/aikBlYohcR1TyQRB9ElQ/yz6Vb3QXJoe01vOJlR287X5/HwuewxAKFZTW Gk2a8DGsUvAfNQ9ik/92atDSpo/QEOu+GAUKmWe7KuJFR2kFm7fBsML7Bou0vEvPpG x0uiwBUmBpmyq2ECpt8H+5KW3Cnu09k45VP7tsmL+EOxFkOyEA7V3z+YVxKPQuu2bL U0n0YsyEJEv0w== From: Jonathan Cameron To: linux-iio@vger.kernel.org, devicetree@vger.kernel.org, Rob Herring , Frank Rowand Cc: Julia Lawall , Nicolas Palix , Sumera Priyadarsini , Jonathan Cameron Subject: [PATCH 1/4] of: Add cleanup.h based auto release via __free(device_node) markings. Date: Sun, 14 Jan 2024 16:53:55 +0000 Message-ID: <20240114165358.119916-2-jic23@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240114165358.119916-1-jic23@kernel.org> References: <20240114165358.119916-1-jic23@kernel.org> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Jonathan Cameron 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() 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 --- include/linux/of.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/of.h b/include/linux/of.h index 6a9ddf20e79a..50e882ee91da 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -13,6 +13,7 @@ */ #include #include +#include #include #include #include @@ -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;