With this patch we try to kill 2 birds with 1 stone.
First of all, some switches that use tag_ocelot.c don't have the exact
same bitfield layout for the DSA tags. The destination ports field is
different for Seville VSC9953 for example. So the choices are to either
duplicate tag_ocelot.c into a new tag_seville.c (sub-optimal) or somehow
take into account a supposed ocelot->dest_ports_offset when packing this
field into the DSA injection header (again not ideal).
Secondly, tag_ocelot.c already needs to memset a 128-bit area to zero
and call some packing() functions of dubious performance in the
fastpath. And most of the values it needs to pack are pretty much
constant (BYPASS=1, SRC_PORT=CPU, DEST=port index). So it would be good
if we could improve that.
The proposed solution is to allocate a memory area per port at probe
time, initialize that with the statically defined bits as per chip
hardware revision, and just perform a simpler memcpy in the fastpath.
Other alternatives have been analyzed, such as:
- Create a separate tag_seville.c: too much code duplication for just 1
bit field difference.
- Create a separate DSA_TAG_PROTO_SEVILLE under tag_ocelot.c, just like
tag_brcm.c, which would have a separate .xmit function. Again, too
much code duplication for just 1 bit field difference.
- Allocate the template from the init function of the tag_ocelot.c
module, instead of from the driver: couldn't figure out a method of
accessing the correct port template corresponding to the correct
tagger in the .xmit function.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, devlink_port_attrs_set accepts a long list of parameters,
that most of them are devlink port's attributes.
Use the devlink_port_attrs struct to replace the relevant parameters.
Signed-off-by: Danielle Ratson <danieller@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This implements the known parts of the Realtek 4 byte
tag protocol version 0xA, as found in the RTL8366RB
DSA switch.
It is designated as protocol version 0xA as a
different Realtek 4 byte tag format with protocol
version 0x9 is known to exist in the Realtek RTL8306
chips.
The tag and switch chip lacks public documentation, so
the tag format has been reverse-engineered from
packet dumps. As only ingress traffic has been available
for analysis an egress tag has not been possible to
develop (even using educated guesses about bit fields)
so this is as far as it gets. It is not known if the
switch even supports egress tagging.
Excessive attempts to figure out the egress tag format
was made. When nothing else worked, I just tried all bit
combinations with 0xannp where a is protocol and p is
port. I looped through all values several times trying
to get a response from ping, without any positive
result.
Using just these ingress tags however, the switch
functionality is vastly improved and the packets find
their way into the destination port without any
tricky VLAN configuration. On the D-Link DIR-685 the
LAN ports now come up and respond to ping without
any command line configuration so this is a real
improvement for users.
Egress packets need to be restricted to the proper
target ports using VLAN, which the RTL8366RB DSA
switch driver already sets up.
Cc: DENG Qingfang <dqfext@gmail.com>
Cc: Mauri Sandberg <sandberg@mailfence.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/dsa/tag_qca.c:48:15: warning: incorrect type in assignment (different base types)
net/dsa/tag_qca.c:48:15: expected unsigned short [usertype]
net/dsa/tag_qca.c:48:15: got restricted __be16 [usertype]
net/dsa/tag_qca.c:68:13: warning: incorrect type in assignment (different base types)
net/dsa/tag_qca.c:68:13: expected restricted __be16 [usertype] hdr
net/dsa/tag_qca.c:68:13: got int
net/dsa/tag_qca.c:71:16: warning: restricted __be16 degrades to integer
net/dsa/tag_qca.c:81:17: warning: restricted __be16 degrades to integer
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/dsa/tag_mtk.c:84:13: warning: incorrect type in assignment (different base types)
net/dsa/tag_mtk.c:84:13: expected restricted __be16 [usertype] hdr
net/dsa/tag_mtk.c:84:13: got int
net/dsa/tag_mtk.c:94:17: warning: restricted __be16 degrades to integer
The result of a ntohs() is not __be16, but u16.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/dsa/tag_lan9303.c:76:24: warning: incorrect type in assignment (different base types)
net/dsa/tag_lan9303.c:76:24: expected unsigned short [usertype]
net/dsa/tag_lan9303.c:76:24: got restricted __be16 [usertype]
net/dsa/tag_lan9303.c:80:24: warning: incorrect type in assignment (different base types)
net/dsa/tag_lan9303.c:80:24: expected unsigned short [usertype]
net/dsa/tag_lan9303.c:80:24: got restricted __be16 [usertype]
net/dsa/tag_lan9303.c:106:31: warning: restricted __be16 degrades to integer
net/dsa/tag_lan9303.c:111:24: warning: cast to restricted __be16
net/dsa/tag_lan9303.c:111:24: warning: cast to restricted __be16
net/dsa/tag_lan9303.c:111:24: warning: cast to restricted __be16
net/dsa/tag_lan9303.c:111:24: warning: cast to restricted __be16
Make use of __be16 where appropriate to fix these warnings.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
cpu_to_be16 returns a __be16 value. So what it is assigned to needs to
have the same type to avoid warnings.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/dsa/slave.c:505:13: warning: incorrect type in initializer (different address spaces)
net/dsa/slave.c:505:13: expected void const [noderef] <asn:3> *__vpp_verify
net/dsa/slave.c:505:13: got struct pcpu_sw_netstats *
Add the needed _percpu property to prevent this warning.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is not very informative to know the DSA master device when a
subordinate network device fails to get its PHY setup. Provide the
device name and capitalize PHY while we are it.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
The driver for Marvell switches puts all ports in IGMP snooping mode
which results in all IGMP/MLD frames that ingress on the ports to be
forwarded to the CPU only.
The bridge code in the kernel can then interpret these frames and act
upon them, for instance by updating the mdb in the switch to reflect
multicast memberships of stations connected to the ports. However,
the IGMP/MLD frames must then also be forwarded to other ports of the
bridge so external IGMP queriers can track membership reports, and
external multicast clients can receive query reports from foreign IGMP
queriers.
Currently, this is impossible as the EDSA tagger sets offload_fwd_mark
on the skb when it unwraps the tagged frames, and that will make the
switchdev layer prevent the skb from egressing on any other port of
the same switch.
To fix that, look at the To_CPU code in the DSA header and make
forwarding of the frame possible for trapped IGMP packets.
Introduce some #defines for the frame types to make the code a bit more
comprehensive.
This was tested on a Marvell 88E6352 variant.
Signed-off-by: Daniel Mack <daniel@zonque.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking fixes from David Miller:
1) Fix cfg80211 deadlock, from Johannes Berg.
2) RXRPC fails to send norigications, from David Howells.
3) MPTCP RM_ADDR parsing has an off by one pointer error, fix from
Geliang Tang.
4) Fix crash when using MSG_PEEK with sockmap, from Anny Hu.
5) The ucc_geth driver needs __netdev_watchdog_up exported, from
Valentin Longchamp.
6) Fix hashtable memory leak in dccp, from Wang Hai.
7) Fix how nexthops are marked as FDB nexthops, from David Ahern.
8) Fix mptcp races between shutdown and recvmsg, from Paolo Abeni.
9) Fix crashes in tipc_disc_rcv(), from Tuong Lien.
10) Fix link speed reporting in iavf driver, from Brett Creeley.
11) When a channel is used for XSK and then reused again later for XSK,
we forget to clear out the relevant data structures in mlx5 which
causes all kinds of problems. Fix from Maxim Mikityanskiy.
12) Fix memory leak in genetlink, from Cong Wang.
13) Disallow sockmap attachments to UDP sockets, it simply won't work.
From Lorenz Bauer.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (83 commits)
net: ethernet: ti: ale: fix allmulti for nu type ale
net: ethernet: ti: am65-cpsw-nuss: fix ale parameters init
net: atm: Remove the error message according to the atomic context
bpf: Undo internal BPF_PROBE_MEM in BPF insns dump
libbpf: Support pre-initializing .bss global variables
tools/bpftool: Fix skeleton codegen
bpf: Fix memlock accounting for sock_hash
bpf: sockmap: Don't attach programs to UDP sockets
bpf: tcp: Recv() should return 0 when the peer socket is closed
ibmvnic: Flush existing work items before device removal
genetlink: clean up family attributes allocations
net: ipa: header pad field only valid for AP->modem endpoint
net: ipa: program upper nibbles of sequencer type
net: ipa: fix modem LAN RX endpoint id
net: ipa: program metadata mask differently
ionic: add pcie_print_link_status
rxrpc: Fix race between incoming ACK parser and retransmitter
net/mlx5: E-Switch, Fix some error pointer dereferences
net/mlx5: Don't fail driver on failure to create debugfs
net/mlx5e: CT: Fix ipv6 nat header rewrite actions
...
Since commit 84af7a6194 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.
This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.
There are a variety of indentation styles found.
a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'
In order to convert all of them to 1 tab + 'help', I ran the
following commend:
$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
The dynamic key update for addr_list_lock still causes troubles,
for example the following race condition still exists:
CPU 0: CPU 1:
(RCU read lock) (RTNL lock)
dev_mc_seq_show() netdev_update_lockdep_key()
-> lockdep_unregister_key()
-> netif_addr_lock_bh()
because lockdep doesn't provide an API to update it atomically.
Therefore, we have to move it back to static keys and use subclass
for nest locking like before.
In commit 1a33e10e4a ("net: partially revert dynamic lockdep key
changes"), I already reverted most parts of commit ab92d68fc2
("net: core: add generic lockdep keys").
This patch reverts the rest and also part of commit f3b0a18bb6
("net: remove unnecessary variables and callback"). After this
patch, addr_list_lock changes back to using static keys and
subclasses to satisfy lockdep. Thanks to dev->lower_level, we do
not have to change back to ->ndo_get_lock_subclass().
And hopefully this reduces some syzbot lockdep noises too.
Reported-by: syzbot+f3a0e80c34b3fc28ac5e@syzkaller.appspotmail.com
Cc: Taehee Yoo <ap420073@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
xdp_umem.c had overlapping changes between the 64-bit math fix
for the calculation of npgs and the removal of the zerocopy
memory type which got rid of the chunk_size_nohdr member.
The mlx5 Kconfig conflict is a case where we just take the
net-next copy of the Kconfig entry dependency as it takes on
the ESWITCH dependency by one level of indirection which is
what the 'net' conflicting change is trying to ensure.
Signed-off-by: David S. Miller <davem@davemloft.net>
Right now, our only tag_8021q user, sja1105, has the ability to restore
bridge VLANs on its own, so this logic is unnecessary.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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
1a33e10e4a ("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 ab92d68fc2 ("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: ab92d68fc2 ("net: core: add generic lockdep keys")
Suggested-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The MSCC bug fix in 'net' had to be slightly adjusted because the
register accesses are done slightly differently in net-next.
Signed-off-by: David S. Miller <davem@davemloft.net>
When a client moves from a DSA user port to a software port in a bridge,
it cannot reach any other clients that connected to the DSA user ports.
That is because SA learning on the CPU port is disabled, so the switch
ignores the client's frames from the CPU port and still thinks it is at
the user port.
Fix it by enabling SA learning on the CPU port.
To prevent the switch from learning from flooding frames from the CPU
port, set skb->offload_fwd_mark to 1 for unicast and broadcast frames,
and let the switch flood them instead of trapping to the CPU port.
Multicast frames still need to be trapped to the CPU port for snooping,
so set the SA_DIS bit of the MTK tag to 1 when transmitting those frames
to disable SA learning.
Fixes: b8f126a8d5 ("net-next: dsa: add dsa support for Mediatek MT7530 switch")
Signed-off-by: DENG Qingfang <dqfext@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A comparison between a value from the packet and an integer constant
value needs to be done by converting the value from the packet from
net->host, or the constant from host->net. Not the other way around.
Even though it makes no practical difference, correct that.
Fixes: 38b5beeae7 ("net: dsa: sja1105: prepare tagger for handling DSA tags and VLAN simultaneously")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Create a subvlan_map as part of each port's tagger private structure.
This keeps reverse mappings of bridge-to-dsa_8021q VLAN retagging rules.
Note that as of this patch, this piece of code is never engaged, due to
the fact that the driver hasn't installed any retagging rule, so we'll
always see packets with a subvlan code of 0 (untagged).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For switches that support VLAN retagging, such as sja1105, we extend
dsa_8021q by encoding a "sub-VLAN" into the remaining 3 free bits in the
dsa_8021q tag.
A sub-VLAN is nothing more than a number in the range 0-7, which serves
as an index into a per-port driver lookup table. The sub-VLAN value of
zero means that traffic is untagged (this is also backwards-compatible
with dsa_8021q without retagging).
The switch should be configured to retag VLAN-tagged traffic that gets
transmitted towards the CPU port (and towards the CPU only). Example:
bridge vlan add dev sw1p0 vid 100
The switch retags frames received on port 0, going to the CPU, and
having VID 100, to the VID of 1104 (0x0450). In dsa_8021q language:
| 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
+-----------+-----+-----------------+-----------+-----------------------+
| DIR | SVL | SWITCH_ID | SUBVLAN | PORT |
+-----------+-----+-----------------+-----------+-----------------------+
0x0450 means:
- DIR = 0b01: this is an RX VLAN
- SUBVLAN = 0b001: this is subvlan #1
- SWITCH_ID = 0b001: this is switch 1 (see the name "sw1p0")
- PORT = 0b0000: this is port 0 (see the name "sw1p0")
The driver also remembers the "1 -> 100" mapping. In the hotpath, if the
sub-VLAN from the tag encodes a non-untagged frame, this mapping is used
to create a VLAN hwaccel tag, with the value of 100.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In VLAN-unaware mode, sja1105 uses VLAN tags with a custom TPID of
0xdadb. While in the yet-to-be introduced best_effort_vlan_filtering
mode, it needs to work with normal VLAN TPID values.
A complication arises when we must transmit a VLAN-tagged packet to the
switch when it's in VLAN-aware mode. We need to construct a packet with
2 VLAN tags, and the switch will use the outer header for routing and
pop it on egress. But sadly, here the 2 hardware generations don't
behave the same:
- E/T switches won't pop an ETH_P_8021AD tag on egress, it seems
(packets will remain double-tagged).
- P/Q/R/S switches will drop a packet with 2 ETH_P_8021Q tags (it looks
like it tries to prevent VLAN hopping).
But looks like the reverse is also true:
- E/T switches have no problem popping the outer tag from packets with
2 ETH_P_8021Q tags.
- P/Q/R/S will have no problem popping a single tag even if that is
ETH_P_8021AD.
So it is clear that if we want the hardware to work with dsa_8021q
tagging in VLAN-aware mode, we need to send different TPIDs depending on
revision. Keep that information in priv->info->qinq_tpid.
The per-port tagger structure will hold an xmit_tpid value that depends
not only upon the qinq_tpid, but also upon the VLAN awareness state
itself (in case we must transmit using 0xdadb).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Managing the VLAN table that is present in hardware will become very
difficult once we add a third operating state
(best_effort_vlan_filtering). That is because correct cleanup (not too
little, not too much) becomes virtually impossible, when VLANs can be
added from the bridge layer, from dsa_8021q for basic tagging, for
cross-chip bridging, as well as retagging rules for sub-VLANs and
cross-chip sub-VLANs. So we need to rethink VLAN interaction with the
switch in a more scalable way.
In preparation for that, use the priv->expect_dsa_8021q boolean to
classify any VLAN request received through .port_vlan_add or
.port_vlan_del towards either one of 2 internal lists: bridge VLANs and
dsa_8021q VLANs.
Then, implement a central sja1105_build_vlan_table method that creates a
VLAN configuration from scratch based on the 2 lists of VLANs kept by
the driver, and based on the VLAN awareness state. Currently, if we are
VLAN-unaware, install the dsa_8021q VLANs, otherwise the bridge VLANs.
Then, implement a delta commit procedure that identifies which VLANs
from this new configuration are actually different from the config
previously committed to hardware. We apply the delta through the dynamic
configuration interface (we don't reset the switch). The result is that
the hardware should see the exact sequence of operations as before this
patch.
This also helps remove the "br" argument passed to
dsa_8021q_crosschip_bridge_join, which it was only using to figure out
whether it should commit the configuration back to us or not, based on
the VLAN awareness state of the bridge. We can simplify that, by always
allowing those VLANs inside of our dsa_8021q_vlans list, and committing
those to hardware when necessary.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This function returns a boolean denoting whether the VLAN passed as
argument is part of the 1024-3071 range that the dsa_8021q tagging
scheme uses.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
DSA assumes that a bridge which has vlan filtering disabled is not
vlan aware, and ignores all vlan configuration. However, the kernel
software bridge code allows configuration in this state.
This causes the kernel's idea of the bridge vlan state and the
hardware state to disagree, so "bridge vlan show" indicates a correct
configuration but the hardware lacks all configuration. Even worse,
enabling vlan filtering on a DSA bridge immediately blocks all traffic
which, given the output of "bridge vlan show", is very confusing.
Provide an option that drivers can set to indicate they want to receive
vlan configuration even when vlan filtering is disabled. At the very
least, this is safe for Marvell DSA bridges, which do not look up
ingress traffic in the VTU if the port is in 8021Q disabled state. It is
also safe for the Ocelot switch family. Whether this change is suitable
for all DSA bridges is not known.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sja1105_netdev_ops should be const since that is what the DSA layer
expects.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ocelot_netdev_ops should be const since that is what the DSA layer
expects.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sja1105 uses dsa_8021q for DSA tagging, a format which is VLAN at heart
and which is compatible with cascading. A complete description of this
tagging format is in net/dsa/tag_8021q.c, but a quick summary is that
each external-facing port tags incoming frames with a unique pvid, and
this special VLAN is transmitted as tagged towards the inside of the
system, and as untagged towards the exterior. The tag encodes the switch
id and the source port index.
This means that cross-chip bridging for dsa_8021q only entails adding
the dsa_8021q pvids of one switch to the RX filter of the other
switches. Everything else falls naturally into place, as long as the
bottom-end of ports (the leaves in the tree) is comprised exclusively of
dsa_8021q-compatible (i.e. sja1105 switches). Otherwise, there would be
a chance that a front-panel switch transmits a packet tagged with a
dsa_8021q header, header which it wouldn't be able to remove, and which
would hence "leak" out.
The only use case I tested (due to lack of board availability) was when
the sja1105 switches are part of disjoint trees (however, this doesn't
change the fact that multiple sja1105 switches still need unique switch
identifiers in such a system). But in principle, even "true" single-tree
setups (with DSA links) should work just as fine, except for a small
change which I can't test: dsa_towards_port should be used instead of
dsa_upstream_port (I made the assumption that the routing port that any
sja1105 should use towards its neighbours is the CPU port. That might
not hold true in other setups).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Somewhat similar to dsa_tree_find, dsa_switch_find returns a dsa_switch
structure pointer by searching for its tree index and switch index (the
parameters from dsa,member). To be used, for example, by drivers who
implement .crosschip_bridge_join and need a reference to the other
switch indicated to by the tree_index and sw_index arguments.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
One way of utilizing DSA is by cascading switches which do not all have
compatible taggers. Consider the following real-life topology:
+---------------------------------------------------------------+
| LS1028A |
| +------------------------------+ |
| | DSA master for Felix | |
| |(internal ENETC port 2: eno2))| |
| +------------+------------------------------+-------------+ |
| | Felix embedded L2 switch | |
| | | |
| | +--------------+ +--------------+ +--------------+ | |
| | |DSA master for| |DSA master for| |DSA master for| | |
| | | SJA1105 1 | | SJA1105 2 | | SJA1105 3 | | |
| | |(Felix port 1)| |(Felix port 2)| |(Felix port 3)| | |
+--+-+--------------+---+--------------+---+--------------+--+--+
+-----------------------+ +-----------------------+ +-----------------------+
| SJA1105 switch 1 | | SJA1105 switch 2 | | SJA1105 switch 3 |
+-----+-----+-----+-----+ +-----+-----+-----+-----+ +-----+-----+-----+-----+
|sw1p0|sw1p1|sw1p2|sw1p3| |sw2p0|sw2p1|sw2p2|sw2p3| |sw3p0|sw3p1|sw3p2|sw3p3|
+-----+-----+-----+-----+ +-----+-----+-----+-----+ +-----+-----+-----+-----+
The above can be described in the device tree as follows (obviously not
complete):
mscc_felix {
dsa,member = <0 0>;
ports {
port@4 {
ethernet = <&enetc_port2>;
};
};
};
sja1105_switch1 {
dsa,member = <1 1>;
ports {
port@4 {
ethernet = <&mscc_felix_port1>;
};
};
};
sja1105_switch2 {
dsa,member = <2 2>;
ports {
port@4 {
ethernet = <&mscc_felix_port2>;
};
};
};
sja1105_switch3 {
dsa,member = <3 3>;
ports {
port@4 {
ethernet = <&mscc_felix_port3>;
};
};
};
Basically we instantiate one DSA switch tree for every hardware switch
in the system, but we still give them globally unique switch IDs (will
come back to that later). Having 3 disjoint switch trees makes the
tagger drivers "just work", because net devices are registered for the
3 Felix DSA master ports, and they are also DSA slave ports to the ENETC
port. So packets received on the ENETC port are stripped of their
stacked DSA tags one by one.
Currently, hardware bridging between ports on the same sja1105 chip is
possible, but switching between sja1105 ports on different chips is
handled by the software bridge. This is fine, but we can do better.
In fact, the dsa_8021q tag used by sja1105 is compatible with cascading.
In other words, a sja1105 switch can correctly parse and route a packet
containing a dsa_8021q tag. So if we could enable hardware bridging on
the Felix DSA master ports, cross-chip bridging could be completely
offloaded.
Such as system would be used as follows:
ip link add dev br0 type bridge && ip link set dev br0 up
for port in sw0p0 sw0p1 sw0p2 sw0p3 \
sw1p0 sw1p1 sw1p2 sw1p3 \
sw2p0 sw2p1 sw2p2 sw2p3; do
ip link set dev $port master br0
done
The above makes switching between ports on the same row be performed in
hardware, and between ports on different rows in software. Now assume
the Felix switch ports are called swp0, swp1, swp2. By running the
following extra commands:
ip link add dev br1 type bridge && ip link set dev br1 up
for port in swp0 swp1 swp2; do
ip link set dev $port master br1
done
the CPU no longer sees packets which traverse sja1105 switch boundaries
and can be forwarded directly by Felix. The br1 bridge would not be used
for any sort of traffic termination.
For this to work, we need to give drivers an opportunity to listen for
bridging events on DSA trees other than their own, and pass that other
tree index as argument. I have made the assumption, for the moment, that
the other existing DSA notifiers don't need to be broadcast to other
trees. That assumption might turn out to be incorrect. But in the
meantime, introduce a dsa_broadcast function, similar in purpose to
dsa_port_notify, which is used only by the bridging notifiers.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
netpoll_send_skb() callers seem to leak skb if
the np pointer is NULL. While this should not happen, we
can make the code more robust.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The NL_SET_ERR_MSG_MOD macro is used to report a string describing an
error message to userspace via the netlink extended ACK structure. It
should not have a trailing newline.
Add a cocci script which catches cases where the newline marker is
present. Using this script, fix the handful of cases which accidentally
included a trailing new line.
I couldn't figure out a way to get a patch mode working, so this script
only implements context, report, and org.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As its implementation shows, this is synonimous with calling
dsa_slave_dev_check followed by dsa_slave_to_port, so it is quite simple
already and provides functionality which is already there.
However there is now a need for these functions outside dsa_priv.h, for
example in drivers that perform mirroring and redirection through
tc-flower offloads (they are given raw access to the flow_cls_offload
structure), where they need to call this function on act->dev.
But simply exporting dsa_slave_to_port would make it non-inline and
would result in an extra function call in the hotpath, as can be seen
for example in sja1105:
Before:
000006dc <sja1105_xmit>:
{
6dc: e92d4ff0 push {r4, r5, r6, r7, r8, r9, sl, fp, lr}
6e0: e1a04000 mov r4, r0
6e4: e591958c ldr r9, [r1, #1420] ; 0x58c <- Inline dsa_slave_to_port
6e8: e1a05001 mov r5, r1
6ec: e24dd004 sub sp, sp, #4
u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
6f0: e1c901d8 ldrd r0, [r9, #24]
6f4: ebfffffe bl 0 <dsa_8021q_tx_vid>
6f4: R_ARM_CALL dsa_8021q_tx_vid
u8 pcp = netdev_txq_to_tc(netdev, queue_mapping);
6f8: e1d416b0 ldrh r1, [r4, #96] ; 0x60
u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
6fc: e1a08000 mov r8, r0
After:
000006e4 <sja1105_xmit>:
{
6e4: e92d4ff0 push {r4, r5, r6, r7, r8, r9, sl, fp, lr}
6e8: e1a04000 mov r4, r0
6ec: e24dd004 sub sp, sp, #4
struct dsa_port *dp = dsa_slave_to_port(netdev);
6f0: e1a00001 mov r0, r1
{
6f4: e1a05001 mov r5, r1
struct dsa_port *dp = dsa_slave_to_port(netdev);
6f8: ebfffffe bl 0 <dsa_slave_to_port>
6f8: R_ARM_CALL dsa_slave_to_port
6fc: e1a09000 mov r9, r0
u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
700: e1c001d8 ldrd r0, [r0, #24]
704: ebfffffe bl 0 <dsa_8021q_tx_vid>
704: R_ARM_CALL dsa_8021q_tx_vid
Because we want to avoid possible performance regressions, introduce
this new function which is designed to be public.
Suggested-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When ndo_get_phys_port_name() for the CPU port was added we introduced
an early check for when the DSA master network device in
dsa_master_ndo_setup() already implements ndo_get_phys_port_name(). When
we perform the teardown operation in dsa_master_ndo_teardown() we would
not be checking that cpu_dp->orig_ndo_ops was successfully allocated and
non-NULL initialized.
With network device drivers such as virtio_net, this leads to a NPD as
soon as the DSA switch hanging off of it gets torn down because we are
now assigning the virtio_net device's netdev_ops a NULL pointer.
Fixes: da7b9e9b00 ("net: dsa: Add ndo_get_phys_port_name() for CPU port")
Reported-by: Allen Pais <allen.pais@oracle.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Allen Pais <allen.pais@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This was caused by a poor merge conflict resolution on my side. The
"act = &cls->rule->action.entries[0];" assignment was already present in
the code prior to the patch mentioned below.
Fixes: e13c207528 ("net: dsa: refactor matchall mirred action to separate function")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch reverts the folowing commits:
commit 064ff66e2b
"bonding: add missing netdev_update_lockdep_key()"
commit 53d374979e
"net: avoid updating qdisc_xmit_lock_key in netdev_update_lockdep_key()"
commit 1f26c0d3d2
"net: fix kernel-doc warning in <linux/netdevice.h>"
commit ab92d68fc2
"net: core: add generic lockdep keys"
but keeps the addr_list_lock_key because we still lock
addr_list_lock nestedly on stack devices, unlikely xmit_lock
this is safe because we don't take addr_list_lock on any fast
path.
Reported-and-tested-by: syzbot+aaa6fa4949cc5d9b7b25@syzkaller.appspotmail.com
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Prior to 1d27732f41 ("net: dsa: setup and teardown ports"), we would
not treat failures to set-up an user port as fatal, but after this
commit we would, which is a regression for some systems where interfaces
may be declared in the Device Tree, but the underlying hardware may not
be present (pluggable daughter cards for instance).
Fixes: 1d27732f41 ("net: dsa: setup and teardown ports")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move the callback into the phylink_config structure, rather than
providing a callback to set this up.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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 <bloodyreaper@yandex.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is no reason to fail the probing of the switch if the MTU couldn't
be configured correctly (either the switch port itself, or the host
port) for whatever reason. MTU-sized traffic probably won't work, sure,
but we can still probably limp on and support some form of communication
anyway, which the users would probably appreciate more.
Fixes: bfcb813203 ("net: dsa: configure the MTU for switch ports")
Reported-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
DSA and CPU ports can be configured in two ways. By default, the
driver should configure such ports to there maximum bandwidth. For
most use cases, this is sufficient. When this default is insufficient,
a phylink instance can be bound to such ports, and phylink will
configure the port, e.g. based on fixed-link properties. phylink
assumes the port is initially down. Given that the driver should have
already configured it to its maximum speed, ask the driver to down
the port before instantiating the phylink instance.
Fixes: 30c4a5b0aa ("net: mv88e6xxx: use resolved link config in mac_link_up()")
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fixes: f41071407c85 ("net: dsa: implement auto-normalization of MTU for bridge hardware datapath")
Signed-off-by: kbuild test robot <lkp@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix an oops in dsa_port_phylink_mac_change() caused by a combination
of a20f997010 ("net: dsa: Don't instantiate phylink for CPU/DSA
ports unless needed") and the net-dsa-improve-serdes-integration
series of patches 65b7a2c8e3 ("Merge branch
'net-dsa-improve-serdes-integration'").
Unable to handle kernel NULL pointer dereference at virtual address 00000124
pgd = c0004000
[00000124] *pgd=00000000
Internal error: Oops: 805 [#1] SMP ARM
Modules linked in: tag_edsa spi_nor mtd xhci_plat_hcd mv88e6xxx(+) xhci_hcd armada_thermal marvell_cesa dsa_core ehci_orion libdes phy_armada38x_comphy at24 mcp3021 sfp evbug spi_orion sff mdio_i2c
CPU: 1 PID: 214 Comm: irq/55-mv88e6xx Not tainted 5.6.0+ #470
Hardware name: Marvell Armada 380/385 (Device Tree)
PC is at phylink_mac_change+0x10/0x88
LR is at mv88e6352_serdes_irq_status+0x74/0x94 [mv88e6xxx]
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The approach taken to pass the port policer methods on to drivers is
pragmatic. It is similar to the port mirroring implementation (in that
the DSA core does all of the filter block interaction and only passes
simple operations for the driver to implement) and dissimilar to how
flow-based policers are going to be implemented (where the driver has
full control over the flow_cls_offload data structure).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make room for other actions for the matchall filter by keeping the
mirred argument parsing self-contained in its own function.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is no point in preparing the module name in a buffer. The format
string can be passed diectly to 'request_module()'.
This axes a few lines of code and cleans a few things:
- max len for a driver name is MODULE_NAME_LEN wich is ~ 60 chars,
not 128. It would be down-sized in 'request_module()'
- we should pass the total size of the buffer to 'snprintf()', not the
size minus 1
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Many switches don't have an explicit knob for configuring the MTU
(maximum transmission unit per interface). Instead, they do the
length-based packet admission checks on the ingress interface, for
reasons that are easy to understand (why would you accept a packet in
the queuing subsystem if you know you're going to drop it anyway).
So it is actually the MRU that these switches permit configuring.
In Linux there only exists the IFLA_MTU netlink attribute and the
associated dev_set_mtu function. The comments like to play blind and say
that it's changing the "maximum transfer unit", which is to say that
there isn't any directionality in the meaning of the MTU word. So that
is the interpretation that this patch is giving to things: MTU == MRU.
When 2 interfaces having different MTUs are bridged, the bridge driver
MTU auto-adjustment logic kicks in: what br_mtu_auto_adjust() does is it
adjusts the MTU of the bridge net device itself (and not that of the
slave net devices) to the minimum value of all slave interfaces, in
order for forwarded packets to not exceed the MTU regardless of the
interface they are received and send on.
The idea behind this behavior, and why the slave MTUs are not adjusted,
is that normal termination from Linux over the L2 forwarding domain
should happen over the bridge net device, which _is_ properly limited by
the minimum MTU. And termination over individual slave devices is
possible even if those are bridged. But that is not "forwarding", so
there's no reason to do normalization there, since only a single
interface sees that packet.
The problem with those switches that can only control the MRU is with
the offloaded data path, where a packet received on an interface with
MRU 9000 would still be forwarded to an interface with MRU 1500. And the
br_mtu_auto_adjust() function does not really help, since the MTU
configured on the bridge net device is ignored.
In order to enforce the de-facto MTU == MRU rule for these switches, we
need to do MTU normalization, which means: in order for no packet larger
than the MTU configured on this port to be sent, then we need to limit
the MRU on all ports that this packet could possibly come from. AKA
since we are configuring the MRU via MTU, it means that all ports within
a bridge forwarding domain should have the same MTU.
And that is exactly what this patch is trying to do.
>From an implementation perspective, we try to follow the intent of the
user, otherwise there is a risk that we might livelock them (they try to
change the MTU on an already-bridged interface, but we just keep
changing it back in an attempt to keep the MTU normalized). So the MTU
that the bridge is normalized to is either:
- The most recently changed one:
ip link set dev swp0 master br0
ip link set dev swp1 master br0
ip link set dev swp0 mtu 1400
This sequence will make swp1 inherit MTU 1400 from swp0.
- The one of the most recently added interface to the bridge:
ip link set dev swp0 master br0
ip link set dev swp1 mtu 1400
ip link set dev swp1 master br0
The above sequence will make swp0 inherit MTU 1400 as well.
Suggested-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is useful be able to configure port policers on a switch to accept
frames of various sizes:
- Increase the MTU for better throughput from the default of 1500 if it
is known that there is no 10/100 Mbps device in the network.
- Decrease the MTU to limit the latency of high-priority frames under
congestion, or work around various network segments that add extra
headers to packets which can't be fragmented.
For DSA slave ports, this is mostly a pass-through callback, called
through the regular ndo ops and at probe time (to ensure consistency
across all supported switches).
The CPU port is called with an MTU equal to the largest configured MTU
of the slave ports. The assumption is that the user might want to
sustain a bidirectional conversation with a partner over any switch
port.
The DSA master is configured the same as the CPU port, plus the tagger
overhead. Since the MTU is by definition L2 payload (sans Ethernet
header), it is up to each individual driver to figure out if it needs to
do anything special for its frame tags on the CPU port (it shouldn't
except in special cases). So the MTU does not contain the tagger
overhead on the CPU port.
However the MTU of the DSA master, minus the tagger overhead, is used as
a proxy for the MTU of the CPU port, which does not have a net device.
This is to avoid uselessly calling the .change_mtu function on the CPU
port when nothing should change.
So it is safe to assume that the DSA master and the CPU port MTUs are
apart by exactly the tagger's overhead in bytes.
Some changes were made around dsa_master_set_mtu(), function which was
now removed, for 2 reasons:
- dev_set_mtu() already calls dev_validate_mtu(), so it's redundant to
do the same thing in DSA
- __dev_set_mtu() returns 0 if ops->ndo_change_mtu is an absent method
That is to say, there's no need for this function in DSA, we can safely
call dev_set_mtu() directly, take the rtnl lock when necessary, and just
propagate whatever errors get reported (since the user probably wants to
be informed).
Some inspiration (mainly in the MTU DSA notifier) was taken from a
vaguely similar patch from Murali and Florian, who are credited as
co-developers down below.
Co-developed-by: Murali Krishna Policharla <murali.policharla@broadcom.com>
Signed-off-by: Murali Krishna Policharla <murali.policharla@broadcom.com>
Co-developed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Vladimir Oltean