2e17c71095
Without this patch we have to manually bring up the CPU interface in failsafe mode. This was backported from kernel 5.12. Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> Tested-by: Rafał Miłecki <rafal@milecki.pl>
86 lines
3.4 KiB
Diff
86 lines
3.4 KiB
Diff
From 9d5ef190e5615a7b63af89f88c4106a5bc127974 Mon Sep 17 00:00:00 2001
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From: Vladimir Oltean <vladimir.oltean@nxp.com>
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Date: Fri, 5 Feb 2021 15:37:10 +0200
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Subject: [PATCH] net: dsa: automatically bring up DSA master when opening user
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port
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DSA wants the master interface to be open before the user port is due to
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historical reasons. The promiscuity of interfaces that are down used to
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have issues, as referenced Lennert Buytenhek in commit df02c6ff2e39
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("dsa: fix master interface allmulti/promisc handling").
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The bugfix mentioned there, commit b6c40d68ff64 ("net: only invoke
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dev->change_rx_flags when device is UP"), was basically a "don't do
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that" approach to working around the promiscuity while down issue.
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Further work done by Vlad Yasevich in commit d2615bf45069 ("net: core:
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Always propagate flag changes to interfaces") has resolved the
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underlying issue, and it is strictly up to the DSA and 8021q drivers
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now, it is no longer mandated by the networking core that the master
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interface must be up when changing its promiscuity.
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From DSA's point of view, deciding to error out in dsa_slave_open
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because the master isn't up is
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(a) a bad user experience and
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(b) knocking at an open door.
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Even if there still was an issue with promiscuity while down, DSA could
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still just open the master and avoid it.
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Doing it this way has the additional benefit that user space can now
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remove DSA-specific workarounds, like systemd-networkd with BindCarrier:
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https://github.com/systemd/systemd/issues/7478
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And we can finally remove one of the 2 bullets in the "Common pitfalls
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using DSA setups" chapter.
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Tested with two cascaded DSA switches:
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$ ip link set sw0p2 up
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fsl_enetc 0000:00:00.2 eno2: configuring for fixed/internal link mode
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fsl_enetc 0000:00:00.2 eno2: Link is Up - 1Gbps/Full - flow control rx/tx
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mscc_felix 0000:00:00.5 swp0: configuring for fixed/sgmii link mode
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mscc_felix 0000:00:00.5 swp0: Link is Up - 1Gbps/Full - flow control off
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8021q: adding VLAN 0 to HW filter on device swp0
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sja1105 spi2.0 sw0p2: configuring for phy/rgmii-id link mode
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IPv6: ADDRCONF(NETDEV_CHANGE): eno2: link becomes ready
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IPv6: ADDRCONF(NETDEV_CHANGE): swp0: link becomes ready
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Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
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Reviewed-by: Andrew Lunn <andrew@lunn.ch>
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Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
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Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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---
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Documentation/networking/dsa/dsa.rst | 4 ----
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net/dsa/slave.c | 7 +++++--
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2 files changed, 5 insertions(+), 6 deletions(-)
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--- a/Documentation/networking/dsa/dsa.rst
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+++ b/Documentation/networking/dsa/dsa.rst
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@@ -273,10 +273,6 @@ will not make us go through the switch t
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the Ethernet switch on the other end, expecting a tag will typically drop this
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frame.
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-Slave network devices check that the master network device is UP before allowing
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-you to administratively bring UP these slave network devices. A common
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-configuration mistake is forgetting to bring UP the master network device first.
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-
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Interactions with other subsystems
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==================================
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--- a/net/dsa/slave.c
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+++ b/net/dsa/slave.c
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@@ -70,8 +70,11 @@ static int dsa_slave_open(struct net_dev
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struct dsa_port *dp = dsa_slave_to_port(dev);
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int err;
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- if (!(master->flags & IFF_UP))
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- return -ENETDOWN;
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+ err = dev_open(master, NULL);
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+ if (err < 0) {
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+ netdev_err(dev, "failed to open master %s\n", master->name);
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+ goto out;
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+ }
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if (!ether_addr_equal(dev->dev_addr, master->dev_addr)) {
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err = dev_uc_add(master, dev->dev_addr);
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