Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Rasmus Villemoes <linux@rasmusvillemoes.dk>
To:     Andrew Lunn <andrew@lunn.ch>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Cc:     Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3 2/3] net: dsa: use NET_NAME_PREDICTABLE for user ports with name given in DT
Date:   Wed, 16 Nov 2022 11:52:03 +0100
Message-Id: <20221116105205.1127843-3-linux@rasmusvillemoes.dk>
In-Reply-To: <20221116105205.1127843-1-linux@rasmusvillemoes.dk>
References: <20221115074356.998747-1-linux@rasmusvillemoes.dk>
 <20221116105205.1127843-1-linux@rasmusvillemoes.dk>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When a user port has a label in device tree, the corresponding
netdevice is, to quote include/uapi/linux/netdevice.h, "predictably
named by the kernel". This is also explicitly one of the intended use
cases for NET_NAME_PREDICTABLE, quoting 685343fc3ba6 ("net: add
name_assign_type netdev attribute"):

  NET_NAME_PREDICTABLE:
    The ifname has been assigned by the kernel in a predictable way
    [...] Examples include [...] and names deduced from hardware
    properties (including being given explicitly by the firmware).

Expose that information properly for the benefit of userspace tools
that make decisions based on the name_assign_type attribute,
e.g. a systemd-udev rule with "kernel" in NamePolicy.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 net/dsa/slave.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index d19e9a536b8f..dfefcc4a9ccf 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -2385,7 +2385,7 @@ int dsa_slave_create(struct dsa_port *port)
 
 	if (port->name) {
 		name = port->name;
-		assign_type = NET_NAME_UNKNOWN;
+		assign_type = NET_NAME_PREDICTABLE;
 	} else {
 		name = "eth%d";
 		assign_type = NET_NAME_UNKNOWN;
-- 
2.37.2