netdev - [PATCH AUTOSEL 5.15 6/6] net: loopback: use NET_NAME_PREDICTABLE for name_assign

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Message-Id: <20221212103600.299810-6-sashal@kernel.org>
Date:   Mon, 12 Dec 2022 05:35:58 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Rasmus Villemoes <linux@...musvillemoes.dk>,
        Jacob Keller <jacob.e.keller@...el.com>,
        "David S . Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>, edumazet@...gle.com,
        kuba@...nel.org, pabeni@...hat.com, netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 5.15 6/6] net: loopback: use NET_NAME_PREDICTABLE for name_assign_type

From: Rasmus Villemoes <linux@...musvillemoes.dk>

[ Upstream commit 31d929de5a112ee1b977a89c57de74710894bbbf ]

When the name_assign_type attribute was introduced (commit
685343fc3ba6, "net: add name_assign_type netdev attribute"), the
loopback device was explicitly mentioned as one which would make use
of NET_NAME_PREDICTABLE:

    The name_assign_type attribute gives hints where the interface name of a
    given net-device comes from. These values are currently defined:
...
      NET_NAME_PREDICTABLE:
        The ifname has been assigned by the kernel in a predictable way
        that is guaranteed to avoid reuse and always be the same for a
        given device. Examples include statically created devices like
        the loopback device [...]

Switch to that so that reading /sys/class/net/lo/name_assign_type
produces something sensible instead of returning -EINVAL.

Signed-off-by: Rasmus Villemoes <linux@...musvillemoes.dk>
Reviewed-by: Jacob Keller <jacob.e.keller@...el.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/net/loopback.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index a1c77cc00416..498e5c8013ef 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -208,7 +208,7 @@ static __net_init int loopback_net_init(struct net *net)
 	int err;
 
 	err = -ENOMEM;
-	dev = alloc_netdev(0, "lo", NET_NAME_UNKNOWN, loopback_setup);
+	dev = alloc_netdev(0, "lo", NET_NAME_PREDICTABLE, loopback_setup);
 	if (!dev)
 		goto out;
 
-- 
2.35.1