From patchwork Fri Feb 16 20:31:58 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bartosz Golaszewski X-Patchwork-Id: 774069 Received: from mail-lj1-f169.google.com (mail-lj1-f169.google.com [209.85.208.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B892F139595 for ; Fri, 16 Feb 2024 20:33:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.169 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708115597; cv=none; b=GteaKAIVPUKSuBdBVJTj/EcOivY/XSUHNJChiWwU1sA5cZvqLSX/cZb+ZztrPBvPFC8phUnxCvOYHdXH/oUU54dPitF3Lc+JpG1LU3E2K4Xs+494hBRRPjo9gCi6xmVo6q4K2iVP8+vTQtPZz7/tybQfofNKwSzbjp7J3QUGnkE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708115597; c=relaxed/simple; bh=0QV0XOVkgQZCCrRrdg+X1apPFOwyznZIa0nD2VYHxpg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=r+NIPPgeidEYILV37T70/oaKXDZleyQuy3H/YFoQ0GKDYKuFu3DAQZfxTdUtBF/aCORh8scZMD1BWK3936QHLY2/w7rndOPb2vYIOAR9DjBkhsLbEK7MKS8/gw3YEwgOFUKKyloNsb4bhWp3rlxi7wCckn1OX19W8HUcYMmHoeU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=bgdev.pl; spf=none smtp.mailfrom=bgdev.pl; dkim=pass (2048-bit key) header.d=bgdev-pl.20230601.gappssmtp.com header.i=@bgdev-pl.20230601.gappssmtp.com header.b=JvanfooB; arc=none smtp.client-ip=209.85.208.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=bgdev.pl Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bgdev.pl Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bgdev-pl.20230601.gappssmtp.com header.i=@bgdev-pl.20230601.gappssmtp.com header.b="JvanfooB" Received: by mail-lj1-f169.google.com with SMTP id 38308e7fff4ca-2d0a4e8444dso11595101fa.2 for ; Fri, 16 Feb 2024 12:33:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20230601.gappssmtp.com; s=20230601; t=1708115592; x=1708720392; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Xzau/i70OXFn0nQv+xGSpdZtho+tWjzX+6Y/L0CiXOM=; b=JvanfooBq97Z2sHrKPc3VpFIgrK3j/jFli+kAib5aKwMIanlbpELte4UbuyoKFppIs gnNNEzb8EG5Rd095l7oHT+3g/PZKTMaVbf46FZermOQA/Jmdl2Bwo9Rr0dywTS8lm+h3 +UpB0SaOvcH+gWPHsCZntdeunaiR4eKYBKxtyvCD4T5GU5zPEmO85VyHwbazjpo0p1BI UDYVphdb/Q4JKjwDs/p1480137jM28OZ6Te+HzDNyyDOd+6VCiYSmwFe3SRAI2HgmzNM T7e0rINuN88kEcNUzxrYwBgEasp5p77mMV0Tek2j7T318VT/AKfT0bnxXRAevCYHIOVG jcUQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1708115592; x=1708720392; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Xzau/i70OXFn0nQv+xGSpdZtho+tWjzX+6Y/L0CiXOM=; b=WS1S2x6Q5TrXQSwVzekd/hHSt+9Xe5Lb5H7yusPhx8O8KIyUkDFxMRrsrvNmXPIqW8 +9TfaFs4XQrbwYUh8FENBkG5dlayztN1zXhhZNILruChapd84rH4PFdld5oyHcTkiuMi 3rlFHqnWcAnEu0w73noYxOKjdNRcGd3jCG0rGakDaTZOk2v4E/RKATcRFSBlOx/espaS YvoBNrKflMDxrvozSQom/YQdoaDJIWY13ATVDEXBeml2m8tzabQ/lu1k4bESYw6X2ZAd TkdoIQ6B5CGC6GbtRnwHVRtSB63fLRXt/FO5tLH1XSs2DPXx6NYCZX48arlLSQmfbr2g AXqw== X-Forwarded-Encrypted: i=1; AJvYcCUHhey7950T0cZ/f6tyFVuL5e0wdl79g2QbD+nl7+D661bVl+fK7YQc0S80XnRVuc6+LgiCJKRK1ynhvQJ+k1hMO98cRdttTS2vnlx/1fo= X-Gm-Message-State: AOJu0YxWKe57xAruQbZTEcZ+MqYXGJix2feOGgIvgmmvBD7ba5YKsQrM z2PWK97oZpJPLnDgvUNd+tsH8PcHFI6PTBp/jiCahnnWOYMSCvQYXj/XdX7TG5k= X-Google-Smtp-Source: AGHT+IHDXA1CmYyMRhXqVjoGiSoJb0Qo9lCMPdos1FiMsILNtLiMwId05Qkpwu2DiA7OHYVJNW3yMg== X-Received: by 2002:a05:651c:b0f:b0:2d0:dfa7:fa1a with SMTP id b15-20020a05651c0b0f00b002d0dfa7fa1amr4944359ljr.0.1708115592326; Fri, 16 Feb 2024 12:33:12 -0800 (PST) Received: from brgl-uxlite.home ([2a01:cb1d:334:ac00:7758:12d:16:5f19]) by smtp.gmail.com with ESMTPSA id m5-20020a05600c4f4500b0041253d0acd6sm1420528wmq.47.2024.02.16.12.33.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 16 Feb 2024 12:33:11 -0800 (PST) From: Bartosz Golaszewski To: Marcel Holtmann , Luiz Augusto von Dentz , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Kalle Valo , Bjorn Andersson , Konrad Dybcio , Liam Girdwood , Mark Brown , Catalin Marinas , Will Deacon , Bjorn Helgaas , Bartosz Golaszewski , Saravana Kannan , Geert Uytterhoeven , Arnd Bergmann , Neil Armstrong , Marek Szyprowski , Alex Elder , Srini Kandagatla , Greg Kroah-Hartman , Abel Vesa , Manivannan Sadhasivam , Lukas Wunner , Dmitry Baryshkov Cc: linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, Jonathan Cameron , Bartosz Golaszewski Subject: [PATCH v5 01/18] of: Add cleanup.h based auto release via __free(device_node) markings. Date: Fri, 16 Feb 2024 21:31:58 +0100 Message-Id: <20240216203215.40870-2-brgl@bgdev.pl> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240216203215.40870-1-brgl@bgdev.pl> References: <20240216203215.40870-1-brgl@bgdev.pl> Precedence: bulk X-Mailing-List: linux-wireless@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(). 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 Signed-off-by: Bartosz Golaszewski --- include/linux/of.h | 2 ++ 1 file changed, 2 insertions(+) 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 #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;