kernel/git/stable/linux.git/net/dsa/slave.c, branch linux-5.4.y

net: dsa: destroy the phylink instance on any error in dsa_slave_phy_setup

2021-09-22T10:26:42+00:00

commit 6a52e73368038f47f6618623d75061dc263b26ae upstream. DSA supports connecting to a phy-handle, and has a fallback to a non-OF based method of connecting to an internal PHY on the switch's own MDIO bus, if no phy-handle and no fixed-link nodes were present. The -ENODEV error code from the first attempt (phylink_of_phy_connect) is what triggers the second attempt (phylink_connect_phy). However, when the first attempt returns a different error code than -ENODEV, this results in an unbalance of calls to phylink_create and phylink_destroy by the time we exit the function. The phylink instance has leaked. There are many other error codes that can be returned by phylink_of_phy_connect. For example, phylink_validate returns -EINVAL. So this is a practical issue too. Fixes: aab9c4067d23 ("net: dsa: Plug in PHYLINK support") Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Reviewed-by: Russell King (Oracle) Link: https://lore.kernel.org/r/20210914134331.2303380-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

net: dsa: fix error code getting shifted with 4 in dsa_slave_get_sset_count

2021-06-03T06:59:12+00:00

[ Upstream commit b94cbc909f1d80378a1f541968309e5c1178c98b ] DSA implements a bunch of 'standardized' ethtool statistics counters, namely tx_packets, tx_bytes, rx_packets, rx_bytes. So whatever the hardware driver returns in .get_sset_count(), we need to add 4 to that. That is ok, except that .get_sset_count() can return a negative error code, for example: b53_get_sset_count -> phy_ethtool_get_sset_count -> return -EIO -EIO is -5, and with 4 added to it, it becomes -1, aka -EPERM. One can imagine that certain error codes may even become positive, although based on code inspection I did not see instances of that. Check the error code first, if it is negative return it as-is. Based on a similar patch for dsa_master_get_strings from Dan Carpenter: https://patchwork.kernel.org/project/netdevbpf/patch/YJaSe3RPgn7gKxZv@mwanda/ Fixes: 91da11f870f0 ("net: Distributed Switch Architecture protocol support") Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: dsa: add GRO support via gro_cells

2021-03-11T13:06:48+00:00

commit e131a5634830047923c694b4ce0c3b31745ff01b upstream. gro_cells lib is used by different encapsulating netdevices, such as geneve, macsec, vxlan etc. to speed up decapsulated traffic processing. CPU tag is a sort of "encapsulation", and we can use the same mechs to greatly improve overall DSA performance. skbs are passed to the GRO layer after removing CPU tags, so we don't need any new packet offload types as it was firstly proposed by me in the first GRO-over-DSA variant [1]. The size of struct gro_cells is sizeof(void *), so hot struct dsa_slave_priv becomes only 4/8 bytes bigger, and all critical fields remain in one 32-byte cacheline. The other positive side effect is that drivers for network devices that can be shipped as CPU ports of DSA-driven switches can now use napi_gro_frags() to pass skbs to kernel. Packets built that way are completely non-linear and are likely being dropped without GRO. This was tested on to-be-mainlined-soon Ethernet driver that uses napi_gro_frags(), and the overall performance was on par with the variant from [1], sometimes even better due to minimal overhead. net.core.gro_normal_batch tuning may help to push it to the limit on particular setups and platforms. iperf3 IPoE VLAN NAT TCP forwarding (port1.218 -> port0) setup on 1.2 GHz MIPS board: 5.7-rc2 baseline: [ID] Interval Transfer Bitrate Retr [ 5] 0.00-120.01 sec 9.00 GBytes 644 Mbits/sec 413 sender [ 5] 0.00-120.00 sec 8.99 GBytes 644 Mbits/sec receiver Iface RX packets TX packets eth0 7097731 7097702 port0 426050 6671829 port1 6671681 425862 port1.218 6671677 425851 With this patch: [ID] Interval Transfer Bitrate Retr [ 5] 0.00-120.01 sec 12.2 GBytes 870 Mbits/sec 122 sender [ 5] 0.00-120.00 sec 12.2 GBytes 870 Mbits/sec receiver Iface RX packets TX packets eth0 9474792 9474777 port0 455200 353288 port1 9019592 455035 port1.218 353144 455024 v2: - Add some performance examples in the commit message; - No functional changes. [1] https://lore.kernel.org/netdev/20191230143028.27313-1-alobakin@dlink.ru/ Signed-off-by: Alexander Lobakin Signed-off-by: David S. Miller Cc: Pali Rohár Signed-off-by: Greg Kroah-Hartman

net: dsa: declare lockless TX feature for slave ports

2020-06-03T06:21:38+00:00

commit 2b86cb8299765688c5119fd18d5f436716c81010 upstream. Be there a platform with the following layout: Regular NIC | +----> DSA master for switch port | +----> DSA master for another switch port After changing DSA back to static lockdep class keys in commit 1a33e10e4a95 ("net: partially revert dynamic lockdep key changes"), this kernel splat can be seen: [ 13.361198] ============================================ [ 13.366524] WARNING: possible recursive locking detected [ 13.371851] 5.7.0-rc4-02121-gc32a05ecd7af-dirty #988 Not tainted [ 13.377874] -------------------------------------------- [ 13.383201] swapper/0/0 is trying to acquire lock: [ 13.388004] ffff0000668ff298 (&dsa_slave_netdev_xmit_lock_key){+.-.}-{2:2}, at: __dev_queue_xmit+0x84c/0xbe0 [ 13.397879] [ 13.397879] but task is already holding lock: [ 13.403727] ffff0000661a1698 (&dsa_slave_netdev_xmit_lock_key){+.-.}-{2:2}, at: __dev_queue_xmit+0x84c/0xbe0 [ 13.413593] [ 13.413593] other info that might help us debug this: [ 13.420140] Possible unsafe locking scenario: [ 13.420140] [ 13.426075] CPU0 [ 13.428523] ---- [ 13.430969] lock(&dsa_slave_netdev_xmit_lock_key); [ 13.435946] lock(&dsa_slave_netdev_xmit_lock_key); [ 13.440924] [ 13.440924] *** DEADLOCK *** [ 13.440924] [ 13.446860] May be due to missing lock nesting notation [ 13.446860] [ 13.453668] 6 locks held by swapper/0/0: [ 13.457598] #0: ffff800010003de0 ((&idev->mc_ifc_timer)){+.-.}-{0:0}, at: call_timer_fn+0x0/0x400 [ 13.466593] #1: ffffd4d3fb478700 (rcu_read_lock){....}-{1:2}, at: mld_sendpack+0x0/0x560 [ 13.474803] #2: ffffd4d3fb478728 (rcu_read_lock_bh){....}-{1:2}, at: ip6_finish_output2+0x64/0xb10 [ 13.483886] #3: ffffd4d3fb478728 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x6c/0xbe0 [ 13.492793] #4: ffff0000661a1698 (&dsa_slave_netdev_xmit_lock_key){+.-.}-{2:2}, at: __dev_queue_xmit+0x84c/0xbe0 [ 13.503094] #5: ffffd4d3fb478728 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x6c/0xbe0 [ 13.512000] [ 13.512000] stack backtrace: [ 13.516369] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.7.0-rc4-02121-gc32a05ecd7af-dirty #988 [ 13.530421] Call trace: [ 13.532871] dump_backtrace+0x0/0x1d8 [ 13.536539] show_stack+0x24/0x30 [ 13.539862] dump_stack+0xe8/0x150 [ 13.543271] __lock_acquire+0x1030/0x1678 [ 13.547290] lock_acquire+0xf8/0x458 [ 13.550873] _raw_spin_lock+0x44/0x58 [ 13.554543] __dev_queue_xmit+0x84c/0xbe0 [ 13.558562] dev_queue_xmit+0x24/0x30 [ 13.562232] dsa_slave_xmit+0xe0/0x128 [ 13.565988] dev_hard_start_xmit+0xf4/0x448 [ 13.570182] __dev_queue_xmit+0x808/0xbe0 [ 13.574200] dev_queue_xmit+0x24/0x30 [ 13.577869] neigh_resolve_output+0x15c/0x220 [ 13.582237] ip6_finish_output2+0x244/0xb10 [ 13.586430] __ip6_finish_output+0x1dc/0x298 [ 13.590709] ip6_output+0x84/0x358 [ 13.594116] mld_sendpack+0x2bc/0x560 [ 13.597786] mld_ifc_timer_expire+0x210/0x390 [ 13.602153] call_timer_fn+0xcc/0x400 [ 13.605822] run_timer_softirq+0x588/0x6e0 [ 13.609927] __do_softirq+0x118/0x590 [ 13.613597] irq_exit+0x13c/0x148 [ 13.616918] __handle_domain_irq+0x6c/0xc0 [ 13.621023] gic_handle_irq+0x6c/0x160 [ 13.624779] el1_irq+0xbc/0x180 [ 13.627927] cpuidle_enter_state+0xb4/0x4d0 [ 13.632120] cpuidle_enter+0x3c/0x50 [ 13.635703] call_cpuidle+0x44/0x78 [ 13.639199] do_idle+0x228/0x2c8 [ 13.642433] cpu_startup_entry+0x2c/0x48 [ 13.646363] rest_init+0x1ac/0x280 [ 13.649773] arch_call_rest_init+0x14/0x1c [ 13.653878] start_kernel+0x490/0x4bc Lockdep keys themselves were added in commit ab92d68fc22f ("net: core: add generic lockdep keys"), and it's very likely that this splat existed since then, but I have no real way to check, since this stacked platform wasn't supported by mainline back then. >From Taehee's own words: This patch was considered that all stackable devices have LLTX flag. But the dsa doesn't have LLTX, so this splat happened. After this patch, dsa shares the same lockdep class key. On the nested dsa interface architecture, which you illustrated, the same lockdep class key will be used in __dev_queue_xmit() because dsa doesn't have LLTX. So that lockdep detects deadlock because the same lockdep class key is used recursively although actually the different locks are used. There are some ways to fix this problem. 1. using NETIF_F_LLTX flag. If possible, using the LLTX flag is a very clear way for it. But I'm so sorry I don't know whether the dsa could have LLTX or not. 2. using dynamic lockdep again. It means that each interface uses a separate lockdep class key. So, lockdep will not detect recursive locking. But this way has a problem that it could consume lockdep class key too many. Currently, lockdep can have 8192 lockdep class keys. - you can see this number with the following command. cat /proc/lockdep_stats lock-classes: 1251 [max: 8192] ... The [max: 8192] means that the maximum number of lockdep class keys. If too many lockdep class keys are registered, lockdep stops to work. So, using a dynamic(separated) lockdep class key should be considered carefully. In addition, updating lockdep class key routine might have to be existing. (lockdep_register_key(), lockdep_set_class(), lockdep_unregister_key()) 3. Using lockdep subclass. A lockdep class key could have 8 subclasses. The different subclass is considered different locks by lockdep infrastructure. But "lock-classes" is not counted by subclasses. So, it could avoid stopping lockdep infrastructure by an overflow of lockdep class keys. This approach should also have an updating lockdep class key routine. (lockdep_set_subclass()) 4. Using nonvalidate lockdep class key. The lockdep infrastructure supports nonvalidate lockdep class key type. It means this lockdep is not validated by lockdep infrastructure. So, the splat will not happen but lockdep couldn't detect real deadlock case because lockdep really doesn't validate it. I think this should be used for really special cases. (lockdep_set_novalidate_class()) Further discussion here: https://patchwork.ozlabs.org/project/netdev/patch/20200503052220.4536-2-xiyou.wangcong@gmail.com/ There appears to be no negative side-effect to declaring lockless TX for the DSA virtual interfaces, which means they handle their own locking. So that's what we do to make the splat go away. Patch tested in a wide variety of cases: unicast, multicast, PTP, etc. Fixes: ab92d68fc22f ("net: core: add generic lockdep keys") Suggested-by: Taehee Yoo Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: dsa: fix phylink_start()/phylink_stop() calls

2020-03-18T06:17:39+00:00

[ Upstream commit 8640f8dc6d657ebfb4e67c202ad32c5457858a13 ] Place phylink_start()/phylink_stop() inside dsa_port_enable() and dsa_port_disable(), which ensures that we call phylink_stop() before tearing down phylink - which is a documented requirement. Failure to do so can cause use-after-free bugs. Fixes: 0e27921816ad ("net: dsa: Use PHYLINK for the CPU/DSA ports") Signed-off-by: Russell King Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: core: add generic lockdep keys

2019-10-24T21:53:48+00:00

Some interface types could be nested. (VLAN, BONDING, TEAM, MACSEC, MACVLAN, IPVLAN, VIRT_WIFI, VXLAN, etc..) These interface types should set lockdep class because, without lockdep class key, lockdep always warn about unexisting circular locking. In the current code, these interfaces have their own lockdep class keys and these manage itself. So that there are so many duplicate code around the /driver/net and /net/. This patch adds new generic lockdep keys and some helper functions for it. This patch does below changes. a) Add lockdep class keys in struct net_device - qdisc_running, xmit, addr_list, qdisc_busylock - these keys are used as dynamic lockdep key. b) When net_device is being allocated, lockdep keys are registered. - alloc_netdev_mqs() c) When net_device is being free'd llockdep keys are unregistered. - free_netdev() d) Add generic lockdep key helper function - netdev_register_lockdep_key() - netdev_unregister_lockdep_key() - netdev_update_lockdep_key() e) Remove unnecessary generic lockdep macro and functions f) Remove unnecessary lockdep code of each interfaces. After this patch, each interface modules don't need to maintain their lockdep keys. Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller

net: dsa: Pass ndo_setup_tc slave callback to drivers

2019-09-16T19:32:57+00:00

DSA currently handles shared block filters (for the classifier-action qdisc) in the core due to what I believe are simply pragmatic reasons - hiding the complexity from drivers and offerring a simple API for port mirroring. Extend the dsa_slave_setup_tc function by passing all other qdisc offloads to the driver layer, where the driver may choose what it implements and how. DSA is simply a pass-through in this case. Signed-off-by: Vladimir Oltean Acked-by: Kurt Kanzenbach Reviewed-by: Florian Fainelli Acked-by: Ilias Apalodimas Signed-off-by: David S. Miller

net: dsa: Advertise the VLAN offload netdev ability only if switch supports it

2019-08-28T03:46:26+00:00

When adding a VLAN sub-interface on a DSA slave port, the 8021q core checks NETIF_F_HW_VLAN_CTAG_FILTER and, if the netdev is capable of filtering, calls .ndo_vlan_rx_add_vid or .ndo_vlan_rx_kill_vid to configure the VLAN offloading. DSA sets this up counter-intuitively: it always advertises this netdev feature, but the underlying driver may not actually support VLAN table manipulation. In that case, the DSA core is forced to ignore the error, because not being able to offload the VLAN is still fine - and should result in the creation of a non-accelerated VLAN sub-interface. Change this so that the netdev feature is only advertised for switch drivers that support VLAN manipulation, instead of checking for -EOPNOTSUPP at runtime. Suggested-by: Florian Fainelli Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller

net: dsa: clear VLAN PVID flag for CPU port

2019-08-28T03:17:28+00:00

When the bridge offloads a VLAN on a slave port, we also need to program its dedicated CPU port as a member of the VLAN. Drivers may handle the CPU port's membership as they want. For example, Marvell as a special "Unmodified" mode to pass frames as is through such ports. Even though DSA expects the drivers to handle the CPU port membership, it does not make sense to program user VLANs as PVID on the CPU port. This patch clears this flag before programming the CPU port. Signed-off-by: Vivien Didelot Suggested-by: Vladimir Oltean Signed-off-by: David S. Miller

net: dsa: program VLAN on CPU port from slave

2019-08-28T03:17:28+00:00

DSA currently programs a VLAN on the CPU port implicitly after the related notifier is received by a switch. While we still need to do this transparent programmation of the DSA links in the fabric, programming the CPU port this way may cause problems in some corners such as the tag_8021q driver. Because the dedicated CPU port is specific to a slave, make their programmation explicit a few layers up, in the slave code. Note that technically, DSA links have a dedicated CPU port as well, but since they are only used as conduit between interconnected switches of a fabric, programming them transparently this way is what we want. Signed-off-by: Vivien Didelot Signed-off-by: David S. Miller