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Message-ID: <87k0cwkxib.fsf@waldekranz.com>
Date: Mon, 14 Mar 2022 22:57:48 +0100
From: Tobias Waldekranz <tobias@...dekranz.com>
To: Vladimir Oltean <olteanv@...il.com>
Cc: davem@...emloft.net, kuba@...nel.org, Andrew Lunn <andrew@...n.ch>,
Vivien Didelot <vivien.didelot@...il.com>,
Florian Fainelli <f.fainelli@...il.com>,
Jiri Pirko <jiri@...nulli.us>,
Ivan Vecera <ivecera@...hat.com>,
Roopa Prabhu <roopa@...dia.com>,
Nikolay Aleksandrov <razor@...ckwall.org>,
Russell King <linux@...linux.org.uk>,
Ido Schimmel <idosch@...dia.com>,
Petr Machata <petrm@...dia.com>,
Cooper Lees <me@...perlees.com>,
Matt Johnston <matt@...econstruct.com.au>,
linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
bridge@...ts.linux-foundation.org
Subject: Re: [PATCH v3 net-next 14/14] net: dsa: mv88e6xxx: MST Offloading
On Mon, Mar 14, 2022 at 18:27, Vladimir Oltean <olteanv@...il.com> wrote:
> On Mon, Mar 14, 2022 at 10:52:31AM +0100, Tobias Waldekranz wrote:
>> Allocate a SID in the STU for each MSTID in use by a bridge and handle
>> the mapping of MSTIDs to VLANs using the SID field of each VTU entry.
>>
>> Signed-off-by: Tobias Waldekranz <tobias@...dekranz.com>
>> ---
>> drivers/net/dsa/mv88e6xxx/chip.c | 251 ++++++++++++++++++++++++++++++-
>> drivers/net/dsa/mv88e6xxx/chip.h | 13 ++
>> 2 files changed, 257 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
>> index c14a62aa6a6c..c23dbf37aeec 100644
>> --- a/drivers/net/dsa/mv88e6xxx/chip.c
>> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
>> @@ -1667,24 +1667,32 @@ static int mv88e6xxx_pvt_setup(struct mv88e6xxx_chip *chip)
>> return 0;
>> }
>>
>> -static void mv88e6xxx_port_fast_age(struct dsa_switch *ds, int port)
>> +static void mv88e6xxx_port_fast_age_fid(struct mv88e6xxx_chip *chip, int port,
>> + u16 fid)
>> {
>> - struct mv88e6xxx_chip *chip = ds->priv;
>> int err;
>>
>> - if (dsa_to_port(ds, port)->lag)
>> + if (dsa_to_port(chip->ds, port)->lag)
>> /* Hardware is incapable of fast-aging a LAG through a
>> * regular ATU move operation. Until we have something
>> * more fancy in place this is a no-op.
>> */
>> return;
>>
>> - mv88e6xxx_reg_lock(chip);
>> - err = mv88e6xxx_g1_atu_remove(chip, 0, port, false);
>> - mv88e6xxx_reg_unlock(chip);
>> + err = mv88e6xxx_g1_atu_remove(chip, fid, port, false);
>>
>> if (err)
>> - dev_err(ds->dev, "p%d: failed to flush ATU\n", port);
>> + dev_err(chip->ds->dev, "p%d: failed to flush ATU (FID %u)\n",
>> + port, fid);
>> +}
>> +
>> +static void mv88e6xxx_port_fast_age(struct dsa_switch *ds, int port)
>> +{
>> + struct mv88e6xxx_chip *chip = ds->priv;
>> +
>> + mv88e6xxx_reg_lock(chip);
>> + mv88e6xxx_port_fast_age_fid(chip, port, 0);
>> + mv88e6xxx_reg_unlock(chip);
>> }
>>
>> static int mv88e6xxx_vtu_setup(struct mv88e6xxx_chip *chip)
>> @@ -1818,6 +1826,159 @@ static int mv88e6xxx_stu_setup(struct mv88e6xxx_chip *chip)
>> return mv88e6xxx_stu_loadpurge(chip, &stu);
>> }
>>
>> +static int mv88e6xxx_sid_get(struct mv88e6xxx_chip *chip, u8 *sid)
>> +{
>> + DECLARE_BITMAP(busy, MV88E6XXX_N_SID) = { 0 };
>> + struct mv88e6xxx_mst *mst;
>> +
>> + set_bit(0, busy);
>
> __set_bit
>
Ack
>> +
>> + list_for_each_entry(mst, &chip->msts, node) {
>> + set_bit(mst->stu.sid, busy);
>> + }
>
> Up to you, but parentheses are generally not used for single-line blocks.
>
Ack
>> +
>> + *sid = find_first_zero_bit(busy, MV88E6XXX_N_SID);
>> +
>> + return (*sid >= mv88e6xxx_max_sid(chip)) ? -ENOSPC : 0;
>> +}
>> +
>> +static int mv88e6xxx_mst_put(struct mv88e6xxx_chip *chip, u8 sid)
>> +{
>> + struct mv88e6xxx_mst *mst, *tmp;
>> + int err;
>> +
>> + if (!sid)
>> + return 0;
>
> Very minor nitpick: since mv88e6xxx_mst_put already checks this, could
> you drop the "!sid" check from callers?
Dropping
>> +
>> + list_for_each_entry_safe(mst, tmp, &chip->msts, node) {
>> + if (mst->stu.sid != sid)
>> + continue;
>> +
>> + if (!refcount_dec_and_test(&mst->refcnt))
>> + return 0;
>> +
>> + mst->stu.valid = false;
>> + err = mv88e6xxx_stu_loadpurge(chip, &mst->stu);
>> + if (err)
>
> Should we bother with a refcount_set(&mst->refcount, 1) on error?
We might as well. Thanks.
>> + return err;
>> +
>> + list_del(&mst->node);
>> + kfree(mst);
>> + return 0;
>> + }
>> +
>> + return -ENOENT;
>> +}
>> +
>> +static int mv88e6xxx_mst_get(struct mv88e6xxx_chip *chip, struct net_device *br,
>> + u16 msti, u8 *sid)
>> +{
>> + struct mv88e6xxx_mst *mst;
>> + int err, i;
>> +
>> + if (!mv88e6xxx_has_stu(chip)) {
>> + err = -EOPNOTSUPP;
>> + goto err;
>> + }
>> +
>> + if (!msti) {
>> + *sid = 0;
>> + return 0;
>> + }
>> +
>> + list_for_each_entry(mst, &chip->msts, node) {
>> + if (mst->br == br && mst->msti == msti) {
>> + refcount_inc(&mst->refcnt);
>> + *sid = mst->stu.sid;
>> + return 0;
>> + }
>> + }
>> +
>> + err = mv88e6xxx_sid_get(chip, sid);
>> + if (err)
>> + goto err;
>> +
>> + mst = kzalloc(sizeof(*mst), GFP_KERNEL);
>> + if (!mst) {
>> + err = -ENOMEM;
>> + goto err;
>> + }
>> +
>> + INIT_LIST_HEAD(&mst->node);
>> + refcount_set(&mst->refcnt, 1);
>> + mst->br = br;
>> + mst->msti = msti;
>> + mst->stu.valid = true;
>> + mst->stu.sid = *sid;
>> +
>> + /* The bridge starts out all ports in the disabled state. But
>> + * a STU state of disabled means to go by the port-global
>> + * state. So we set all user port's initial state to blocking,
>> + * to match the bridge's behavior.
>> + */
>> + for (i = 0; i < mv88e6xxx_num_ports(chip); i++)
>> + mst->stu.state[i] = dsa_is_user_port(chip->ds, i) ?
>> + MV88E6XXX_PORT_CTL0_STATE_BLOCKING :
>> + MV88E6XXX_PORT_CTL0_STATE_DISABLED;
>> +
>> + err = mv88e6xxx_stu_loadpurge(chip, &mst->stu);
>> + if (err)
>> + goto err_free;
>> +
>> + list_add_tail(&mst->node, &chip->msts);
>> + return 0;
>> +
>> +err_free:
>> + kfree(mst);
>> +err:
>> + return err;
>> +}
>> +
>> +static int mv88e6xxx_port_mst_state_set(struct dsa_switch *ds, int port,
>> + const struct switchdev_mst_state *st)
>> +{
>> + struct dsa_port *dp = dsa_to_port(ds, port);
>> + struct mv88e6xxx_chip *chip = ds->priv;
>> + struct mv88e6xxx_mst *mst;
>> + u8 state;
>> + int err;
>> +
>> + if (!mv88e6xxx_has_stu(chip))
>> + return -EOPNOTSUPP;
>> +
>> + switch (st->state) {
>> + case BR_STATE_DISABLED:
>> + case BR_STATE_BLOCKING:
>> + case BR_STATE_LISTENING:
>> + state = MV88E6XXX_PORT_CTL0_STATE_BLOCKING;
>> + break;
>> + case BR_STATE_LEARNING:
>> + state = MV88E6XXX_PORT_CTL0_STATE_LEARNING;
>> + break;
>> + case BR_STATE_FORWARDING:
>> + state = MV88E6XXX_PORT_CTL0_STATE_FORWARDING;
>> + break;
>> + default:
>> + return -EINVAL;
>> + }
>> +
>> + list_for_each_entry(mst, &chip->msts, node) {
>> + if (mst->br == dsa_port_bridge_dev_get(dp) &&
>> + mst->msti == st->msti) {
>> + if (mst->stu.state[port] == state)
>> + return 0;
>> +
>> + mst->stu.state[port] = state;
>> + mv88e6xxx_reg_lock(chip);
>> + err = mv88e6xxx_stu_loadpurge(chip, &mst->stu);
>> + mv88e6xxx_reg_unlock(chip);
>> + return err;
>> + }
>> + }
>> +
>> + return -ENOENT;
>> +}
>> +
>> static int mv88e6xxx_port_check_hw_vlan(struct dsa_switch *ds, int port,
>> u16 vid)
>> {
>> @@ -2437,6 +2598,12 @@ static int mv88e6xxx_port_vlan_leave(struct mv88e6xxx_chip *chip,
>> if (err)
>> return err;
>>
>> + if (!vlan.valid && vlan.sid) {
>> + err = mv88e6xxx_mst_put(chip, vlan.sid);
>> + if (err)
>> + return err;
>> + }
>> +
>> return mv88e6xxx_g1_atu_remove(chip, vlan.fid, port, false);
>> }
>>
>> @@ -2482,6 +2649,72 @@ static int mv88e6xxx_port_vlan_del(struct dsa_switch *ds, int port,
>> return err;
>> }
>>
>> +static void mv88e6xxx_port_vlan_fast_age(struct dsa_switch *ds, int port, u16 vid)
>> +{
>> + struct mv88e6xxx_chip *chip = ds->priv;
>> + struct mv88e6xxx_vtu_entry vlan;
>> + int err;
>> +
>> + mv88e6xxx_reg_lock(chip);
>> +
>> + err = mv88e6xxx_vtu_get(chip, vid, &vlan);
>> + if (err)
>> + goto unlock;
>> +
>> + mv88e6xxx_port_fast_age_fid(chip, port, vlan.fid);
>> +
>> +unlock:
>> + mv88e6xxx_reg_unlock(chip);
>> +
>> + if (err)
>> + dev_err(ds->dev, "p%d: failed to flush ATU in VID %u\n",
>> + port, vid);
>
> This error message actually corresponds to an mv88e6xxx_vtu_get() error,
> so the message is kind of incorrect. mv88e6xxx_port_fast_age_fid(),
> whose error code isn't propagated here, has its own "failed to flush ATU"
> error message.
Not sure I agree. If this fails, the symptom will be lingering dynamic
entries in the affected VLAN. In that case I think the current message,
or something similar, will make it as easy as possible to establish a
correlation.
Yes, it failed because the VTU get op failed, but that is more of an
internal affair in the driver.
Anyway, it's a moot point, because I think we should just allow the
error to bubble up to userspace instead - as you suggested in 11/14.
>> +}
>
> Otherwise this looks pretty good.
Careful now, don't spoil me :)
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