From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,FAKE_REPLY_C,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8CEA6C43332 for ; Wed, 18 Mar 2020 22:22:44 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5C1B52076E for ; Wed, 18 Mar 2020 22:22:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Z9TnKmiN"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="TeaROXeq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5C1B52076E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:References: List-Owner; bh=ckAWiptulaqHPLFyqTmimGccqAT84oQGeTWC08PCxWI=; b=Z9TnKmiNT+WB2D YcrQvVwfQqx7hfEZ+xW4wIRT8s49VmtwXM/Tfv6SIhLiIGKi6gKSnodPMwrchcHEbmIAkm8+ESfYS h3zmqDpe/cnwc2VeJO0L7cRyvYcOWYFG91A5CEKvqgL3Z5bz68uwOerR3KMQSZfC1coSwjOBQtsfm +Ma8ecvoynVk6c5Ey8MVY1hXsTFCGcCh35Xzg2c/C1ZeDeqVXbley85Cr9Z/dyhe8oC2tvDC3Qp6w dS71SVan2rqlI5Ud17oNFy146IjyMnui/KN0/Eb187EbLXbWSIJjktOnKRAHYZJPq6/0lsuIIGT9O X38Lb6NVyV/DtKVE6piA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jEh5H-0004ST-Tc; Wed, 18 Mar 2020 22:22:43 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jEh5F-0004Rz-EY; Wed, 18 Mar 2020 22:22:42 +0000 Received: from localhost (mobile-166-175-186-165.mycingular.net [166.175.186.165]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6804D20714; Wed, 18 Mar 2020 22:22:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584570160; bh=Xz/0EvZI1ZYMODHoYRMl9J+dOM/tsbfHznYvsE+DY4A=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=TeaROXeqtIiOuPZEJEeYWnIPHrh1Ask7srNIxIYhwTpKsUqP2jP8EVgIYJM33HfwF 1jFMhhapjJedYXzGwqqv6NFwF3Nch7XWO1iNLYfMzXCjEK5TU34+g7gYssJdkFOM1b DGF8UtEi5MxA8pPt6Acsc8nHRD8W/OlpKBw98Rb4= Date: Wed, 18 Mar 2020 17:22:38 -0500 From: Bjorn Helgaas To: Thomas Gleixner Subject: Re: [PATCH 4/5] pci: handled return value of platform_get_irq correctly Message-ID: <20200318222238.GA247500@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <874kulbwyv.fsf@nanos.tec.linutronix.de> User-Agent: Mutt/1.12.2 (2019-09-21) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200318_152241_531567_CF88EEF6 X-CRM114-Status: GOOD ( 19.24 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Lorenzo Pieralisi , Karthikeyan Mitran , Marc Gonzalez , linux-pci@vger.kernel.org, Linus Walleij , Aman Sharma , linux-kernel@vger.kernel.org, Ryder Lee , linux-mediatek@lists.infradead.org, Thomas Petazzoni , Marc Zyngier , Matthias Brugger , Mans Rullgard , Hou Zhiqiang , linux-arm-kernel@lists.infradead.org, Andrew Murray Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Mar 18, 2020 at 02:42:48PM +0100, Thomas Gleixner wrote: > Bjorn Helgaas writes: > > On Fri, Mar 13, 2020 at 04:56:42PM -0500, Bjorn Helgaas wrote: > >> On Fri, Mar 13, 2020 at 10:05:58PM +0100, Thomas Gleixner wrote: > >> > > I think the best pattern is: > >> > > > >> > > irq = platform_get_irq(pdev, i); > >> > > if (irq < 0) > >> > > return irq; > >> > > >> > Careful. 0 is not a valid interrupt. > >> > >> Should callers of platform_get_irq() check for a 0 return value? > >> About 900 of them do not. > > I don't know what I was looking at. > > platform_get_irq() does the right thing already, so checking for irq < 0 > is sufficient. > > Sorry for the confusion! Thanks, I was indeed confused! Maybe we could reduce future confusion by strengthening the comments slightly, e.g., - * Return: IRQ number on success, negative error number on failure. + * Return: non-zero IRQ number on success, negative error number on failure. I don't want to push my luck, but it's pretty hard to prove that platform_get_irq() never returns 0. What would you think of something like the following? @@ -133,23 +133,24 @@ EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource_byname); * if (irq < 0) * return irq; * - * Return: IRQ number on success, negative error number on failure. + * Return: non-zero IRQ number on success, negative error number on failure. */ int platform_get_irq_optional(struct platform_device *dev, unsigned int num) { + int ret; #ifdef CONFIG_SPARC /* sparc does not have irqs represented as IORESOURCE_IRQ resources */ if (!dev || num >= dev->archdata.num_irqs) return -ENXIO; - return dev->archdata.irqs[num]; + ret = dev->archdata.irqs[num]; + goto out; #else struct resource *r; - int ret; if (IS_ENABLED(CONFIG_OF_IRQ) && dev->dev.of_node) { ret = of_irq_get(dev->dev.of_node, num); if (ret > 0 || ret == -EPROBE_DEFER) - return ret; + goto out; } r = platform_get_resource(dev, IORESOURCE_IRQ, num); @@ -157,7 +158,7 @@ int platform_get_irq_optional(struct platform_device *dev, unsigned int num) if (r && r->flags & IORESOURCE_DISABLED) { ret = acpi_irq_get(ACPI_HANDLE(&dev->dev), num, r); if (ret) - return ret; + goto out; } } @@ -171,13 +172,17 @@ int platform_get_irq_optional(struct platform_device *dev, unsigned int num) struct irq_data *irqd; irqd = irq_get_irq_data(r->start); - if (!irqd) - return -ENXIO; + if (!irqd) { + ret = -ENXIO; + goto out; + } irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); } - if (r) - return r->start; + if (r) { + ret = r->start; + goto out; + } /* * For the index 0 interrupt, allow falling back to GpioInt @@ -190,11 +195,14 @@ int platform_get_irq_optional(struct platform_device *dev, unsigned int num) ret = acpi_dev_gpio_irq_get(ACPI_COMPANION(&dev->dev), num); /* Our callers expect -ENXIO for missing IRQs. */ if (ret >= 0 || ret == -EPROBE_DEFER) - return ret; + goto out; } - return -ENXIO; + ret = -ENXIO; #endif +out: + WARN(ret == 0, "0 is an invalid IRQ number\n"); + return ret; } EXPORT_SYMBOL_GPL(platform_get_irq_optional); @@ -212,7 +220,7 @@ EXPORT_SYMBOL_GPL(platform_get_irq_optional); * if (irq < 0) * return irq; * - * Return: IRQ number on success, negative error number on failure. + * Return: non-zero IRQ number on success, negative error number on failure. */ int platform_get_irq(struct platform_device *dev, unsigned int num) { @@ -284,8 +292,10 @@ static int __platform_get_irq_byname(struct platform_device *dev, } r = platform_get_resource_byname(dev, IORESOURCE_IRQ, name); - if (r) + if (r) { + WARN(r->start == 0, "0 is an invalid IRQ number\n"); return r->start; + } return -ENXIO; } @@ -297,7 +307,7 @@ static int __platform_get_irq_byname(struct platform_device *dev, * * Get an IRQ like platform_get_irq(), but then by name rather then by index. * - * Return: IRQ number on success, negative error number on failure. + * Return: non-zero IRQ number on success, negative error number on failure. */ int platform_get_irq_byname(struct platform_device *dev, const char *name) { @@ -319,7 +329,7 @@ EXPORT_SYMBOL_GPL(platform_get_irq_byname); * Get an optional IRQ by name like platform_get_irq_byname(). Except that it * does not print an error message if an IRQ can not be obtained. * - * Return: IRQ number on success, negative error number on failure. + * Return: non-zero IRQ number on success, negative error number on failure. */ int platform_get_irq_byname_optional(struct platform_device *dev, const char *name) _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel