From patchwork Fri Jul 10 21:20:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Saheed O. Bolarinwa" X-Patchwork-Id: 11657451 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EE1EA739 for ; Fri, 10 Jul 2020 22:20:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D5CD120857 for ; Fri, 10 Jul 2020 22:20:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="vBecEFbh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726624AbgGJWUU (ORCPT ); Fri, 10 Jul 2020 18:20:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726693AbgGJWUS (ORCPT ); Fri, 10 Jul 2020 18:20:18 -0400 Received: from mail-wm1-x341.google.com (mail-wm1-x341.google.com [IPv6:2a00:1450:4864:20::341]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F2DDC08C5DC; Fri, 10 Jul 2020 15:20:18 -0700 (PDT) Received: by mail-wm1-x341.google.com with SMTP id o2so7333253wmh.2; Fri, 10 Jul 2020 15:20:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=zBfQN+vRaGSFliSIC9sUYYBlJBWdf+Mc3nVjYABa6uc=; b=vBecEFbh/d0jSef2GGDkawA1rYeo7al4di1WqcRGBfvnRrTP2sQxtQ0PJwcAgiO5qe MGsc06bJHFGxcuKxJEQnwXXsbhVhwXOIFkM7N/BdSw7KytVkbUqwRgCgR0jvV4AXKVCM mNRjwHqEUbOHu7JVc+2DOTngEfZFUvsXnoFl99OezVwXeJ+rXwhReatDgo1Ck2JO/kxY UZ11NYvdsJyVUZJKJSsdFaD8sfkVHxddqoSvWwfDuAQZt6rXeBv1fUkNJRmaR3d9rvUQ 1wa5IR6Xo1ZY7GKo7UgBdWpgkGe3f+hZpgf596QE3g6SXnBHKtk8tP0bakSwc4saynAE fqdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=zBfQN+vRaGSFliSIC9sUYYBlJBWdf+Mc3nVjYABa6uc=; b=RCAB86vdOv/lJ+qq7BPvtI8I7JSdMKXabcuog0MgKtqLWDv0zIyW7aKLHUKdHe5Fc1 mT8bVfelxZDm3fEzdZl9Krkus1SeZAjH/lGXSAaaKocn25Ct5yVwQh6m2uORxPdA4dH0 6syb8pN5MDBzjtkhysRfOb5LV6Tne6nT+zn1dUbhaJAqSWJzIUw94OGbPdCaTh1nA4jz u3nKr3UayS3ZJc7CElaAqGU/hxwZPkQ/y8kbeCn+uBEqPFV+hVGHG54Xe0pWKlHfXzJx tjq7n7du0St4OVfV15uKqjnHdNlfi0EiVKI6liUnuzq0tR+cbyAZaabifDOLJKBIQxk6 S9Og== X-Gm-Message-State: AOAM530kIlzH+7q8FtL5sWrWPwbZlNas8jH27yonhjJgaky6F9+sq0OA 4c2FR28AyxqjuGErIQF/Pj0= X-Google-Smtp-Source: ABdhPJyfeh9pQCHsK+AR0ZiTfubZZSMON0PFLNp3rQLm4JcDpLNUMt2j2BpVH5xqfzX/lX304gQmIg== X-Received: by 2002:a1c:4086:: with SMTP id n128mr7445658wma.118.1594419616792; Fri, 10 Jul 2020 15:20:16 -0700 (PDT) Received: from net.saheed (54007186.dsl.pool.telekom.hu. [84.0.113.134]) by smtp.gmail.com with ESMTPSA id l18sm12170281wrm.52.2020.07.10.15.20.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Jul 2020 15:20:16 -0700 (PDT) From: Saheed Olayemi Bolarinwa To: helgaas@kernel.org Cc: Bolarinwa Olayemi Saheed , bjorn@helgaas.com, skhan@linuxfoundation.org, linux-pci@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, linux-kernel@vger.kernel.org Subject: [PATCH 7/14 v3] PCI: pciehp: Check the return value of pcie_capability_read_*() Date: Fri, 10 Jul 2020 23:20:19 +0200 Message-Id: <20200710212026.27136-8-refactormyself@gmail.com> X-Mailer: git-send-email 2.18.2 In-Reply-To: <20200710212026.27136-1-refactormyself@gmail.com> References: <20200710212026.27136-1-refactormyself@gmail.com> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Bolarinwa Olayemi Saheed If pcie_capability_read_word() fail, slot_ctrl will be 0 and the switch expression evaluates to 0. So *status = 1 "ON". However, with Patch 14/14 it is possible that slot_ctrl is set to ~0 on failure. This would introduce a bug because (x & x) == (~0 & x), so the switch expression evaluates to PCI_EXP_SLTCTL_PCC. This means that on failure *status = 1 "OFF", since PCI_EXP_SLTCTL_PCC = PCI_EXP_SLTCTL_PWR_OFF. Use an if-statement and include a check on the return value of pcie_capability_read_word() to confirm success or failure. Suggested-by: Bjorn Helgaas Signed-off-by: Bolarinwa Olayemi Saheed --- drivers/pci/hotplug/pciehp_hpc.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index b89c9ee4a3b5..f5ef3fbace69 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -394,20 +394,16 @@ void pciehp_get_power_status(struct controller *ctrl, u8 *status) { struct pci_dev *pdev = ctrl_dev(ctrl); u16 slot_ctrl; + int ret; - pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl); + *status = 1; /* On */ + ret = pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl); ctrl_dbg(ctrl, "%s: SLOTCTRL %x value read %x\n", __func__, pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, slot_ctrl); - switch (slot_ctrl & PCI_EXP_SLTCTL_PCC) { - case PCI_EXP_SLTCTL_PWR_OFF: + if (!ret && + ((slot_ctrl & PCI_EXP_SLTCTL_PCC) == PCI_EXP_SLTCTL_PWR_OFF)) *status = 0; /* Off */ - break; - case PCI_EXP_SLTCTL_PWR_ON: - default: - *status = 1; /* On */ - break; - } } void pciehp_get_latch_status(struct controller *ctrl, u8 *status)