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![Marc Zyngier](/assets/img/avatar_default.png)
Creating a macvtap on a DSA-backed interface results in the following
splat when lockdep is enabled:
[ 19.638080] IPv6: ADDRCONF(NETDEV_CHANGE): lan0: link becomes ready
[ 23.041198] device lan0 entered promiscuous mode
[ 23.043445] device eth0 entered promiscuous mode
[ 23.049255]
[ 23.049557] ============================================
[ 23.055021] WARNING: possible recursive locking detected
[ 23.060490] 5.0.0-rc3-00013-g56c857a1b8d3 #118 Not tainted
[ 23.066132] --------------------------------------------
[ 23.071598] ip/2861 is trying to acquire lock:
[ 23.076171] 00000000f61990cb (_xmit_ETHER){+...}, at: dev_set_rx_mode+0x1c/0x38
[ 23.083693]
[ 23.083693] but task is already holding lock:
[ 23.089696] 00000000ecf0c3b4 (_xmit_ETHER){+...}, at: dev_uc_add+0x24/0x70
[ 23.096774]
[ 23.096774] other info that might help us debug this:
[ 23.103494] Possible unsafe locking scenario:
[ 23.103494]
[ 23.109584] CPU0
[ 23.112093] ----
[ 23.114601] lock(_xmit_ETHER);
[ 23.117917] lock(_xmit_ETHER);
[ 23.121233]
[ 23.121233] *** DEADLOCK ***
[ 23.121233]
[ 23.127325] May be due to missing lock nesting notation
[ 23.127325]
[ 23.134315] 2 locks held by ip/2861:
[ 23.137987] #0: 000000003b766c72 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x338/0x4e0
[ 23.146231] #1: 00000000ecf0c3b4 (_xmit_ETHER){+...}, at: dev_uc_add+0x24/0x70
[ 23.153757]
[ 23.153757] stack backtrace:
[ 23.158243] CPU: 0 PID: 2861 Comm: ip Not tainted 5.0.0-rc3-00013-g56c857a1b8d3 #118
[ 23.166212] Hardware name: Globalscale Marvell ESPRESSOBin Board (DT)
[ 23.172843] Call trace:
[ 23.175358] dump_backtrace+0x0/0x188
[ 23.179116] show_stack+0x14/0x20
[ 23.182524] dump_stack+0xb4/0xec
[ 23.185928] __lock_acquire+0x123c/0x1860
[ 23.190048] lock_acquire+0xc8/0x248
[ 23.193724] _raw_spin_lock_bh+0x40/0x58
[ 23.197755] dev_set_rx_mode+0x1c/0x38
[ 23.201607] dev_set_promiscuity+0x3c/0x50
[ 23.205820] dsa_slave_change_rx_flags+0x5c/0x70
[ 23.210567] __dev_set_promiscuity+0x148/0x1e0
[ 23.215136] __dev_set_rx_mode+0x74/0x98
[ 23.219167] dev_uc_add+0x54/0x70
[ 23.222575] macvlan_open+0x170/0x1d0
[ 23.226336] __dev_open+0xe0/0x160
[ 23.229830] __dev_change_flags+0x16c/0x1b8
[ 23.234132] dev_change_flags+0x20/0x60
[ 23.238074] do_setlink+0x2d0/0xc50
[ 23.241658] __rtnl_newlink+0x5f8/0x6e8
[ 23.245601] rtnl_newlink+0x50/0x78
[ 23.249184] rtnetlink_rcv_msg+0x360/0x4e0
[ 23.253397] netlink_rcv_skb+0xe8/0x130
[ 23.257338] rtnetlink_rcv+0x14/0x20
[ 23.261012] netlink_unicast+0x190/0x210
[ 23.265043] netlink_sendmsg+0x288/0x350
[ 23.269075] sock_sendmsg+0x18/0x30
[ 23.272659] ___sys_sendmsg+0x29c/0x2c8
[ 23.276602] __sys_sendmsg+0x60/0xb8
[ 23.280276] __arm64_sys_sendmsg+0x1c/0x28
[ 23.284488] el0_svc_common+0xd8/0x138
[ 23.288340] el0_svc_handler+0x24/0x80
[ 23.292192] el0_svc+0x8/0xc
This looks fairly harmless (no actual deadlock occurs), and is
fixed in a similar way to c6894dec8e
("bridge: fix lockdep
addr_list_lock false positive splat") by putting the addr_list_lock
in its own lockdep class.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
250 lines
6.5 KiB
C
250 lines
6.5 KiB
C
/*
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* Handling of a master device, switching frames via its switch fabric CPU port
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*
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* Copyright (c) 2017 Savoir-faire Linux Inc.
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* Vivien Didelot <vivien.didelot@savoirfairelinux.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include "dsa_priv.h"
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static void dsa_master_get_ethtool_stats(struct net_device *dev,
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struct ethtool_stats *stats,
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uint64_t *data)
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{
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struct dsa_port *cpu_dp = dev->dsa_ptr;
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const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
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struct dsa_switch *ds = cpu_dp->ds;
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int port = cpu_dp->index;
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int count = 0;
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if (ops->get_sset_count && ops->get_ethtool_stats) {
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count = ops->get_sset_count(dev, ETH_SS_STATS);
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ops->get_ethtool_stats(dev, stats, data);
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}
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if (ds->ops->get_ethtool_stats)
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ds->ops->get_ethtool_stats(ds, port, data + count);
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}
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static void dsa_master_get_ethtool_phy_stats(struct net_device *dev,
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struct ethtool_stats *stats,
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uint64_t *data)
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{
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struct dsa_port *cpu_dp = dev->dsa_ptr;
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const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
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struct dsa_switch *ds = cpu_dp->ds;
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int port = cpu_dp->index;
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int count = 0;
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if (dev->phydev && !ops->get_ethtool_phy_stats) {
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count = phy_ethtool_get_sset_count(dev->phydev);
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if (count >= 0)
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phy_ethtool_get_stats(dev->phydev, stats, data);
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} else if (ops->get_sset_count && ops->get_ethtool_phy_stats) {
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count = ops->get_sset_count(dev, ETH_SS_PHY_STATS);
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ops->get_ethtool_phy_stats(dev, stats, data);
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}
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if (count < 0)
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count = 0;
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if (ds->ops->get_ethtool_phy_stats)
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ds->ops->get_ethtool_phy_stats(ds, port, data + count);
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}
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static int dsa_master_get_sset_count(struct net_device *dev, int sset)
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{
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struct dsa_port *cpu_dp = dev->dsa_ptr;
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const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
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struct dsa_switch *ds = cpu_dp->ds;
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int count = 0;
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if (sset == ETH_SS_PHY_STATS && dev->phydev &&
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!ops->get_ethtool_phy_stats)
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count = phy_ethtool_get_sset_count(dev->phydev);
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else if (ops->get_sset_count)
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count = ops->get_sset_count(dev, sset);
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if (count < 0)
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count = 0;
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if (ds->ops->get_sset_count)
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count += ds->ops->get_sset_count(ds, cpu_dp->index, sset);
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return count;
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}
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static void dsa_master_get_strings(struct net_device *dev, uint32_t stringset,
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uint8_t *data)
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{
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struct dsa_port *cpu_dp = dev->dsa_ptr;
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const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
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struct dsa_switch *ds = cpu_dp->ds;
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int port = cpu_dp->index;
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int len = ETH_GSTRING_LEN;
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int mcount = 0, count;
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unsigned int i;
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uint8_t pfx[4];
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uint8_t *ndata;
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snprintf(pfx, sizeof(pfx), "p%.2d", port);
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/* We do not want to be NULL-terminated, since this is a prefix */
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pfx[sizeof(pfx) - 1] = '_';
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if (stringset == ETH_SS_PHY_STATS && dev->phydev &&
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!ops->get_ethtool_phy_stats) {
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mcount = phy_ethtool_get_sset_count(dev->phydev);
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if (mcount < 0)
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mcount = 0;
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else
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phy_ethtool_get_strings(dev->phydev, data);
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} else if (ops->get_sset_count && ops->get_strings) {
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mcount = ops->get_sset_count(dev, stringset);
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if (mcount < 0)
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mcount = 0;
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ops->get_strings(dev, stringset, data);
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}
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if (ds->ops->get_strings) {
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ndata = data + mcount * len;
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/* This function copies ETH_GSTRINGS_LEN bytes, we will mangle
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* the output after to prepend our CPU port prefix we
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* constructed earlier
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*/
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ds->ops->get_strings(ds, port, stringset, ndata);
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count = ds->ops->get_sset_count(ds, port, stringset);
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for (i = 0; i < count; i++) {
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memmove(ndata + (i * len + sizeof(pfx)),
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ndata + i * len, len - sizeof(pfx));
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memcpy(ndata + i * len, pfx, sizeof(pfx));
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}
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}
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}
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static int dsa_master_ethtool_setup(struct net_device *dev)
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{
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struct dsa_port *cpu_dp = dev->dsa_ptr;
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struct dsa_switch *ds = cpu_dp->ds;
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struct ethtool_ops *ops;
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ops = devm_kzalloc(ds->dev, sizeof(*ops), GFP_KERNEL);
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if (!ops)
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return -ENOMEM;
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cpu_dp->orig_ethtool_ops = dev->ethtool_ops;
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if (cpu_dp->orig_ethtool_ops)
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memcpy(ops, cpu_dp->orig_ethtool_ops, sizeof(*ops));
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ops->get_sset_count = dsa_master_get_sset_count;
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ops->get_ethtool_stats = dsa_master_get_ethtool_stats;
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ops->get_strings = dsa_master_get_strings;
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ops->get_ethtool_phy_stats = dsa_master_get_ethtool_phy_stats;
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dev->ethtool_ops = ops;
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return 0;
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}
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static void dsa_master_ethtool_teardown(struct net_device *dev)
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{
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struct dsa_port *cpu_dp = dev->dsa_ptr;
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dev->ethtool_ops = cpu_dp->orig_ethtool_ops;
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cpu_dp->orig_ethtool_ops = NULL;
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}
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static ssize_t tagging_show(struct device *d, struct device_attribute *attr,
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char *buf)
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{
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struct net_device *dev = to_net_dev(d);
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struct dsa_port *cpu_dp = dev->dsa_ptr;
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return sprintf(buf, "%s\n",
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dsa_tag_protocol_to_str(cpu_dp->tag_ops));
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}
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static DEVICE_ATTR_RO(tagging);
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static struct attribute *dsa_slave_attrs[] = {
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&dev_attr_tagging.attr,
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NULL
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};
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static const struct attribute_group dsa_group = {
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.name = "dsa",
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.attrs = dsa_slave_attrs,
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};
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static void dsa_master_set_mtu(struct net_device *dev, struct dsa_port *cpu_dp)
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{
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unsigned int mtu = ETH_DATA_LEN + cpu_dp->tag_ops->overhead;
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int err;
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rtnl_lock();
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if (mtu <= dev->max_mtu) {
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err = dev_set_mtu(dev, mtu);
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if (err)
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netdev_dbg(dev, "Unable to set MTU to include for DSA overheads\n");
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}
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rtnl_unlock();
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}
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static void dsa_master_reset_mtu(struct net_device *dev)
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{
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int err;
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rtnl_lock();
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err = dev_set_mtu(dev, ETH_DATA_LEN);
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if (err)
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netdev_dbg(dev,
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"Unable to reset MTU to exclude DSA overheads\n");
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rtnl_unlock();
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}
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static struct lock_class_key dsa_master_addr_list_lock_key;
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int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
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{
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int ret;
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dsa_master_set_mtu(dev, cpu_dp);
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/* If we use a tagging format that doesn't have an ethertype
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* field, make sure that all packets from this point on get
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* sent to the tag format's receive function.
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*/
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wmb();
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dev->dsa_ptr = cpu_dp;
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lockdep_set_class(&dev->addr_list_lock,
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&dsa_master_addr_list_lock_key);
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ret = dsa_master_ethtool_setup(dev);
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if (ret)
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return ret;
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ret = sysfs_create_group(&dev->dev.kobj, &dsa_group);
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if (ret)
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dsa_master_ethtool_teardown(dev);
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return ret;
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}
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void dsa_master_teardown(struct net_device *dev)
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{
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sysfs_remove_group(&dev->dev.kobj, &dsa_group);
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dsa_master_ethtool_teardown(dev);
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dsa_master_reset_mtu(dev);
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dev->dsa_ptr = NULL;
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/* If we used a tagging format that doesn't have an ethertype
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* field, make sure that all packets from this point get sent
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* without the tag and go through the regular receive path.
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*/
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wmb();
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}
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