[PATCH v2] r8169: Avoid duplicate sysfs entry creation error

From: Andre Przywara
Date: Thu Jun 24 2021 - 11:50:23 EST

From: Sayanta Pattanayak <sayanta.pattanayak@xxxxxxx>

When registering the MDIO bus for a r8169 device, we use the PCI B/D/F
specifier as a (seemingly) unique device identifier.
However the very same BDF number can be used on another PCI segment,
which makes the driver fail probing:

[ 27.544136] r8169 0002:07:00.0: enabling device (0000 -> 0003)
[ 27.559734] sysfs: cannot create duplicate filename '/class/mdio_bus/r8169-700'
[ 27.684858] libphy: mii_bus r8169-700 failed to register
[ 27.695602] r8169: probe of 0002:07:00.0 failed with error -22

Add the segment number to the device name to make it more unique.

This fixes operation on an ARM N1SDP board, where two boards might be
connected together to form an SMP system, and all on-board devices show
up twice, just on different PCI segments.

Signed-off-by: Sayanta Pattanayak <sayanta.pattanayak@xxxxxxx>
[Andre: expand commit message, use pci_domain_nr()]
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
Now compile-tested on ARM, arm64, ppc64, sparc64, mips64, hppa, x86-64,

Changes v1 ... v2:
- use pci_domain_nr() wrapper to fix compilation on various arches

drivers/net/ethernet/realtek/r8169_main.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index 2c89cde7da1e..5f7f0db7c502 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -5086,7 +5086,8 @@ static int r8169_mdio_register(struct rtl8169_private *tp)
new_bus->priv = tp;
new_bus->parent = &pdev->dev;
new_bus->irq[0] = PHY_MAC_INTERRUPT;
- snprintf(new_bus->id, MII_BUS_ID_SIZE, "r8169-%x", pci_dev_id(pdev));
+ snprintf(new_bus->id, MII_BUS_ID_SIZE, "r8169-%x-%x",
+ pci_domain_nr(pdev->bus), pci_dev_id(pdev));

new_bus->read = r8169_mdio_read_reg;
new_bus->write = r8169_mdio_write_reg;