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Subject: Re: [PATCH net v3] r8169: Avoid duplicate sysfs entry creation error
To:     Andre Przywara <andre.przywara@arm.com>, nic_swsd@realtek.com
Cc:     "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Sayanta Pattanayak <sayanta.pattanayak@arm.com>
References: <20210720161740.5214-1-andre.przywara@arm.com>
From:   Heiner Kallweit <hkallweit1@gmail.com>
Message-ID: <c5e8d932-b9f6-f05c-91ab-10d9cd6878fc@gmail.com>
Date:   Tue, 20 Jul 2021 21:17:20 +0200
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On 20.07.2021 18:17, Andre Przywara wrote:
> From: Sayanta Pattanayak <sayanta.pattanayak@arm.com>
> 
> When registering the MDIO bus for a r8169 device, we use the PCI
> bus/device 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 ARM N1SDP boards, with two boards connected
> together to form an SMP system, and all on-board devices showing up
> twice, just on different PCI segments. A similar issue would occur on
> large systems with many PCI slots and multiple RTL8169 NICs.
> 
> Fixes: f1e911d5d0dfd ("r8169: add basic phylib support")
> Signed-off-by: Sayanta Pattanayak <sayanta.pattanayak@arm.com>
> [Andre: expand commit message, use pci_domain_nr()]
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
> Compile-tested on ARM, arm64, ppc64, sparc64, mips64, hppa, x86-64,
> i386. Tested on an AMD system with an on-board RTL8111 chip.
> 
> Changes v2 ... v3:
> - Resent with Fixes tag and proper net: annotation
> 
> 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 f744557c33a3..c7af5bc3b8af 100644
> --- a/drivers/net/ethernet/realtek/r8169_main.c
> +++ b/drivers/net/ethernet/realtek/r8169_main.c
> @@ -5084,7 +5084,8 @@ 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;
> 

Acked-by: Heiner Kallweit <hkallweit1@gmail.com>