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  1. 12 Jan, 2021 5 commits
    • Vladimir Oltean's avatar
      net: switchdev: remove the transaction structure from port attributes · bae33f2b
      Vladimir Oltean authored 
      Since the introduction of the switchdev API, port attributes were
transmitted to drivers for offloading using a two-step transactional
model, with a prepare phase that was supposed to catch all errors, and a
commit phase that was supposed to never fail.

Some classes of failures can never be avoided, like hardware access, or
memory allocation. In the latter case, merely attempting to move the
memory allocation to the preparation phase makes it impossible to avoid
memory leaks, since commit 91cf8ece ("switchdev: Remove unused
transaction item queue") which has removed the unused mechanism of
passing on the allocated memory between one phase and another.

It is time we admit that separating the preparation from the commit
phase is something that is best left for the driver to decide, and not
something that should be baked into the API, especially since there are
no switchdev callers that depend on this.

This patch removes the struct switchdev_trans member from switchdev port
attribute notifier structures, and converts drivers to not look at this
member.

In part, this patch contains a revert of my previous commit 2e554a7a
("net: dsa: propagate switchdev vlan_filtering prepare phase to
drivers").

For the most part, the conversion was trivial except for:
- Rocker's world implementation based on Broadcom OF-DPA had an odd
  implementation of ofdpa_port_attr_bridge_flags_set. The conversion was
  done mechanically, by pasting the implementation twice, then only
  keeping the code that would get executed during prepare phase on top,
  then only keeping the code that gets executed during the commit phase
  on bottom, then simplifying the resulting code until this was obtained.
- DSA's offloading of STP state, bridge flags, VLAN filtering and
  multicast router could be converted right away. But the ageing time
  could not, so a shim was introduced and this was left for a further
  commit.
Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Acked-by: default avatarJiri Pirko <jiri@nvidia.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de> # hellcreek
Reviewed-by: Linus Walleij <linus.walleij@linaro.org> # RTL8366RB
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Reviewed-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      bae33f2b
    • Vladimir Oltean's avatar
      net: switchdev: delete switchdev_port_obj_add_now · cf6def51
      Vladimir Oltean authored 
      After the removal of the transactional model inside
switchdev_port_obj_add_now, it has no added value and we can just call
switchdev_port_obj_notify directly, bypassing this function. Let's
delete it.
Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Acked-by: default avatarJiri Pirko <jiri@nvidia.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      cf6def51
    • Vladimir Oltean's avatar
      net: switchdev: remove the transaction structure from port object notifiers · ffb68fc5
      Vladimir Oltean authored 
      Since the introduction of the switchdev API, port objects were
transmitted to drivers for offloading using a two-step transactional
model, with a prepare phase that was supposed to catch all errors, and a
commit phase that was supposed to never fail.

Some classes of failures can never be avoided, like hardware access, or
memory allocation. In the latter case, merely attempting to move the
memory allocation to the preparation phase makes it impossible to avoid
memory leaks, since commit 91cf8ece ("switchdev: Remove unused
transaction item queue") which has removed the unused mechanism of
passing on the allocated memory between one phase and another.

It is time we admit that separating the preparation from the commit
phase is something that is best left for the driver to decide, and not
something that should be baked into the API, especially since there are
no switchdev callers that depend on this.

This patch removes the struct switchdev_trans member from switchdev port
object notifier structures, and converts drivers to not look at this
member.

Where driver conversion is trivial (like in the case of the Marvell
Prestera driver, NXP DPAA2 switch, TI CPSW, and Rocker drivers), it is
done in this patch.

Where driver conversion needs more attention (DSA, Mellanox Spectrum),
the conversion is left for subsequent patches and here we only fake the
prepare/commit phases at a lower level, just not in the switchdev
notifier itself.

Where the code has a natural structure that is best left alone as a
preparation and a commit phase (as in the case of the Ocelot switch),
that structure is left in place, just made to not depend upon the
switchdev transactional model.
Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Acked-by: default avatarJiri Pirko <jiri@nvidia.com>
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      ffb68fc5
    • Vladimir Oltean's avatar
      net: dsa: mv88e6xxx: deny vid 0 on the CPU port and DSA links too · 3e85f580
      Vladimir Oltean authored 
      mv88e6xxx apparently has a problem offloading VID 0, which the 8021q
module tries to install as part of commit ad1afb00 ("vlan_dev: VLAN
0 should be treated as "no vlan tag" (802.1p packet)"). That mv88e6xxx
restriction seems to have been introduced by the "VTU GetNext VID-1
trick to retrieve a single entry" - see commit 2fb5ef09 ("net: dsa:
mv88e6xxx: extract single VLAN retrieval").

There is one more problem. The mv88e6xxx CPU port and DSA links do not
report properly in the prepare phase what are the VLANs that they can
offload. They'll say they can offload everything:

mv88e6xxx_port_vlan_prepare
-> mv88e6xxx_port_check_hw_vlan:

	/* DSA and CPU ports have to be members of multiple vlans */
	if (dsa_is_dsa_port(ds, port) || dsa_is_cpu_port(ds, port))
		return 0;

Except that if you actually try to commit to it, they'll error out and
print this message:

[   32.802438] mv88e6085 d0032004.mdio-mii:12: p9: failed to add VLAN 0t

which comes from:

mv88e6xxx_port_vlan_add
-> mv88e6xxx_port_vlan_join:

	if (!vid)
		return -EOPNOTSUPP;

What prevents this condition from triggering in real life? The fact that
when a DSA_NOTIFIER_VLAN_ADD is emitted, it never targets a DSA link
directly. Instead, the notifier will always target either a user port or
a CPU port. DSA links just happen to get dragged in by:

static bool dsa_switch_vlan_match(struct dsa_switch *ds, int port,
				  struct dsa_notifier_vlan_info *info)
{
	...
	if (dsa_is_dsa_port(ds, port))
		return true;
	...
}

So for every DSA VLAN notifier, during the prepare phase, it will just
so happen that there will be somebody to say "no, don't do that".

This will become a problem when the switchdev prepare/commit transactional
model goes away. Every port needs to think on its own. DSA links can no
longer bluff and rely on the fact that the prepare phase will not go
through to the end, because there will be no prepare phase any longer.

Fix this issue before it becomes a problem, by having the "vid == 0"
check earlier than the check whether we are a CPU port / DSA link or not.
Also, the "vid == 0" check becomes unnecessary in the .port_vlan_add
callback, so we can remove it.
Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      3e85f580
    • Vladimir Oltean's avatar
      net: switchdev: remove vid_begin -> vid_end range from VLAN objects · b7a9e0da
      Vladimir Oltean authored 
      The call path of a switchdev VLAN addition to the bridge looks something
like this today:

        nbp_vlan_init
        |  __br_vlan_set_default_pvid
        |  |                       |
        |  |    br_afspec          |
        |  |        |              |
        |  |        v              |
        |  | br_process_vlan_info  |
        |  |        |              |
        |  |        v              |
        |  |   br_vlan_info        |
        |  |       / \            /
        |  |      /   \          /
        |  |     /     \        /
        |  |    /       \      /
        v  v   v         v    v
      nbp_vlan_add   br_vlan_add ------+
       |              ^      ^ |       |
       |             /       | |       |
       |            /       /  /       |
       \ br_vlan_get_master/  /        v
        \        ^        /  /  br_vlan_add_existing
         \       |       /  /          |
          \      |      /  /          /
           \     |     /  /          /
            \    |    /  /          /
             \   |   /  /          /
              v  |   | v          /
              __vlan_add         /
                 / |            /
                /  |           /
               v   |          /
   __vlan_vid_add  |         /
               \   |        /
                v  v        v
      br_switchdev_port_vlan_add

The ranges UAPI was introduced to the bridge in commit bdced7ef
("bridge: support for multiple vlans and vlan ranges in setlink and
dellink requests") (Jan 10 2015). But the VLAN ranges (parsed in br_afspec)
have always been passed one by one, through struct bridge_vlan_info
tmp_vinfo, to br_vlan_info. So the range never went too far in depth.

Then Scott Feldman introduced the switchdev_port_bridge_setlink function
in commit 47f8328b ("switchdev: add new switchdev bridge setlink").
That marked the introduction of the SWITCHDEV_OBJ_PORT_VLAN, which made
full use of the range. But switchdev_port_bridge_setlink was called like
this:

br_setlink
-> br_afspec
-> switchdev_port_bridge_setlink

Basically, the switchdev and the bridge code were not tightly integrated.
Then commit 41c498b9 ("bridge: restore br_setlink back to original")
came, and switchdev drivers were required to implement
.ndo_bridge_setlink = switchdev_port_bridge_setlink for a while.

In the meantime, commits such as 0944d6b5 ("bridge: try switchdev op
first in __vlan_vid_add/del") finally made switchdev penetrate the
br_vlan_info() barrier and start to develop the call path we have today.
But remember, br_vlan_info() still receives VLANs one by one.

Then Arkadi Sharshevsky refactored the switchdev API in 2017 in commit
29ab586c ("net: switchdev: Remove bridge bypass support from
switchdev") so that drivers would not implement .ndo_bridge_setlink any
longer. The switchdev_port_bridge_setlink also got deleted.
This refactoring removed the parallel bridge_setlink implementation from
switchdev, and left the only switchdev VLAN objects to be the ones
offloaded from __vlan_vid_add (basically RX filtering) and  __vlan_add
(the latter coming from commit 9c86ce2c ("net: bridge: Notify about
bridge VLANs")).

That is to say, today the switchdev VLAN object ranges are not used in
the kernel. Refactoring the above call path is a bit complicated, when
the bridge VLAN call path is already a bit complicated.

Let's go off and finish the job of commit 29ab586c by deleting the
bogus iteration through the VLAN ranges from the drivers. Some aspects
of this feature never made too much sense in the first place. For
example, what is a range of VLANs all having the BRIDGE_VLAN_INFO_PVID
flag supposed to mean, when a port can obviously have a single pvid?
This particular configuration _is_ denied as of commit 6623c60d
("bridge: vlan: enforce no pvid flag in vlan ranges"), but from an API
perspective, the driver still has to play pretend, and only offload the
vlan->vid_end as pvid. And the addition of a switchdev VLAN object can
modify the flags of another, completely unrelated, switchdev VLAN
object! (a VLAN that is PVID will invalidate the PVID flag from whatever
other VLAN had previously been offloaded with switchdev and had that
flag. Yet switchdev never notifies about that change, drivers are
supposed to guess).

Nonetheless, having a VLAN range in the API makes error handling look
scarier than it really is - unwinding on errors and all of that.
When in reality, no one really calls this API with more than one VLAN.
It is all unnecessary complexity.

And despite appearing pretentious (two-phase transactional model and
all), the switchdev API is really sloppy because the VLAN addition and
removal operations are not paired with one another (you can add a VLAN
100 times and delete it just once). The bridge notifies through
switchdev of a VLAN addition not only when the flags of an existing VLAN
change, but also when nothing changes. There are switchdev drivers out
there who don't like adding a VLAN that has already been added, and
those checks don't really belong at driver level. But the fact that the
API contains ranges is yet another factor that prevents this from being
addressed in the future.

Of the existing switchdev pieces of hardware, it appears that only
Mellanox Spectrum supports offloading more than one VLAN at a time,
through mlxsw_sp_port_vlan_set. I have kept that code internal to the
driver, because there is some more bookkeeping that makes use of it, but
I deleted it from the switchdev API. But since the switchdev support for
ranges has already been de facto deleted by a Mellanox employee and
nobody noticed for 4 years, I'm going to assume it's not a biggie.
Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com> # switchdev and mlxsw
Reviewed-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de> # hellcreek
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      b7a9e0da
  3. 11 Jan, 2021 1 commit
  5. 10 Jan, 2021 24 commits
  7. 09 Jan, 2021 10 commits
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