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From:   Naveen Naidu <naveennaidu479@gmail.com>
To:     bhelgaas@google.com
Cc:     Naveen Naidu <naveennaidu479@gmail.com>,
        linux-kernel-mentees@lists.linuxfoundation.org,
        linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        skhan@linuxfoundation.org,
        Nirmal Patel <nirmal.patel@linux.intel.com>,
        Jonathan Derrick <jonathan.derrick@linux.dev>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Rob Herring <robh@kernel.org>,
        =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= <kw@linux.com>
Subject: [PATCH v3 17/25] PCI: vmd: Use RESPONSE_IS_PCI_ERROR() to check read from hardware
Date:   Thu, 21 Oct 2021 20:37:42 +0530
Message-Id: <5be1fdfdcf4b4a453117ef4dea0f71c9555fac24.1634825082.git.naveennaidu479@gmail.com>
In-Reply-To: <cover.1634825082.git.naveennaidu479@gmail.com>
References: <cover.1634825082.git.naveennaidu479@gmail.com>
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An MMIO read from a PCI device that doesn't exist or doesn't respond
causes a PCI error.  There's no real data to return to satisfy the
CPU read, so most hardware fabricates ~0 data.

Use RESPONSE_IS_PCI_ERROR() to check the response we get when we read
data from hardware.

This helps unify PCI error response checking and make error checks
consistent and easier to find.

Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/controller/vmd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index a5987e52700e..bfe6b002ffec 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -538,7 +538,7 @@ static int vmd_get_phys_offsets(struct vmd_dev *vmd, bool native_hint,
 		int ret;
 
 		ret = pci_read_config_dword(dev, PCI_REG_VMLOCK, &vmlock);
-		if (ret || vmlock == ~0)
+		if (ret || RESPONSE_IS_PCI_ERROR(vmlock))
 			return -ENODEV;
 
 		if (MB2_SHADOW_EN(vmlock)) {
-- 
2.25.1