[PATCH v2 3/6] PCI/VPD: Treat initial 0xff as missing EEPROM

[Bjorn Helgaas <helgaas@kernel.org>]

From: Heiner Kallweit <hkallweit1@gmail.com>

Previously we assumed that the first tag being 0x00 meant an EEPROM was
missing.  The first tag being 0xff means the same thing; check for that
also.

[bhelgaas: rework error mesage]
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/vpd.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c
index 9b54dd95e42c..66703de2cf2b 100644
--- a/drivers/pci/vpd.c
+++ b/drivers/pci/vpd.c
@@ -78,10 +78,8 @@ static size_t pci_vpd_size(struct pci_dev *dev, size_t old_size)
 	while (off < old_size && pci_read_vpd(dev, off, 1, header) == 1) {
 		unsigned char tag;
 
-		if (!header[0] && !off) {
-			pci_info(dev, "Invalid VPD tag 00, assume missing optional VPD EPROM\n");
-			return 0;
-		}
+		if (off == 0 && (header[0] == 0x00 || header[0] == 0xff))
+			goto error;
 
 		if (header[0] & PCI_VPD_LRDT) {
 			/* Large Resource Data Type Tag */
@@ -113,6 +111,12 @@ static size_t pci_vpd_size(struct pci_dev *dev, size_t old_size)
 		}
 	}
 	return 0;
+
+error:
+	pci_info(dev, "invalid VPD tag %#04x at offset %zu%s\n",
+		 header[0], off, off == 0 ?
+		 "; assume missing optional EEPROM" : "");
+	return 0;
 }
 
 /*
-- 
2.25.1