linux-kernel - [PATCH v3 6/9] cxl/pci: Do not ignore PCI config read errors in match_add

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Message-ID: <20221109104059.766720-7-rrichter@amd.com>
Date:   Wed, 9 Nov 2022 11:40:56 +0100
From:   Robert Richter <rrichter@....com>
To:     Alison Schofield <alison.schofield@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Ben Widawsky <bwidawsk@...nel.org>,
        Dan Williams <dan.j.williams@...el.com>
CC:     <linux-cxl@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Len Brown <lenb@...nel.org>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        "Davidlohr Bueso" <dave@...olabs.net>,
        Dave Jiang <dave.jiang@...el.com>,
        Robert Richter <rrichter@....com>
Subject: [PATCH v3 6/9] cxl/pci: Do not ignore PCI config read errors in match_add_dports()

The link capabilities of a PCI device are read when enumerating its
dports. This is done by reading the PCI config space. If that fails
port enumeration ignores that error. However, reading the PCI config
space should reliably work.

To reduce some complexity to the code flow when factoring out parts of
the code in match_add_dports() for later reuse, change this to throw
an error.

Signed-off-by: Robert Richter <rrichter@....com>
---
 drivers/cxl/core/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index 0dbbe8d39b07..8271b8abde7a 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -47,7 +47,7 @@ static int match_add_dports(struct pci_dev *pdev, void *data)
 		return 0;
 	if (pci_read_config_dword(pdev, pci_pcie_cap(pdev) + PCI_EXP_LNKCAP,
 				  &lnkcap))
-		return 0;
+		return -ENXIO;
 
 	rc = cxl_find_regblock(pdev, CXL_REGLOC_RBI_COMPONENT, &map);
 	if (rc)
-- 
2.30.2