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Message-ID: <df5b0110-0440-9c01-d7ec-5fbfb92acdb2@bang-olufsen.dk>
Date: Mon, 6 Dec 2021 11:01:52 +0000
From: Alvin Šipraga <ALSI@...g-olufsen.dk>
To: Vladimir Oltean <vladimir.oltean@....com>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC: Florian Fainelli <f.fainelli@...il.com>,
Andrew Lunn <andrew@...n.ch>,
Vivien Didelot <vivien.didelot@...il.com>,
Tobias Waldekranz <tobias@...dekranz.com>,
DENG Qingfang <dqfext@...il.com>,
Kurt Kanzenbach <kurt@...utronix.de>,
Hauke Mehrtens <hauke@...ke-m.de>,
Woojung Huh <woojung.huh@...rochip.com>,
"UNGLinuxDriver@...rochip.com" <UNGLinuxDriver@...rochip.com>,
Sean Wang <sean.wang@...iatek.com>,
Landen Chao <Landen.Chao@...iatek.com>,
Matthias Brugger <matthias.bgg@...il.com>,
Claudiu Manoil <claudiu.manoil@....com>,
Alexandre Belloni <alexandre.belloni@...tlin.com>,
Linus Walleij <linus.walleij@...aro.org>,
George McCollister <george.mccollister@...il.com>
Subject: Re: [PATCH v2 net-next 7/7] net: dsa: eliminate dsa_switch_ops ::
port_bridge_tx_fwd_{,un}offload
On 12/4/21 21:11, Vladimir Oltean wrote:
> We don't really need new switch API for these, and with new switches
> which intend to add support for this feature, it will become cumbersome
> to maintain.
>
> The change consists in restructuring the two drivers that implement this
> offload (sja1105 and mv88e6xxx) such that the offload is enabled and
> disabled from the ->port_bridge_{join,leave} methods instead of the old
> ->port_bridge_tx_fwd_{,un}offload.
>
> The only non-trivial change is that mv88e6xxx_map_virtual_bridge_to_pvt()
> has been moved to avoid a forward declaration, and the
> mv88e6xxx_reg_lock() calls from inside it have been removed, since
> locking is now done from mv88e6xxx_port_bridge_{join,leave}.
>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
> ---
Reviewed-by: Alvin Šipraga <alsi@...g-olufsen.dk>
> v1->v2: avoid a deadlock in mv88e6xxx pointed out by Tobias due to the
> register lock being already held in the port_bridge_join/leave
> methods. Again had to drop Alvin's Reviewed-by tag.
>
> drivers/net/dsa/mv88e6xxx/chip.c | 63 ++++++++++----------------
> drivers/net/dsa/sja1105/sja1105_main.c | 19 ++++++--
> include/net/dsa.h | 7 +--
> net/dsa/port.c | 39 ++--------------
> 4 files changed, 45 insertions(+), 83 deletions(-)
>
> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
> index c30d1f825776..ec515045c16e 100644
> --- a/drivers/net/dsa/mv88e6xxx/chip.c
> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> @@ -2451,6 +2451,19 @@ static int mv88e6xxx_bridge_map(struct mv88e6xxx_chip *chip,
> return 0;
> }
>
> +/* Treat the software bridge as a virtual single-port switch behind the
> + * CPU and map in the PVT. First dst->last_switch elements are taken by
> + * physical switches, so start from beyond that range.
> + */
> +static int mv88e6xxx_map_virtual_bridge_to_pvt(struct dsa_switch *ds,
> + unsigned int bridge_num)
> +{
> + u8 dev = bridge_num + ds->dst->last_switch;
> + struct mv88e6xxx_chip *chip = ds->priv;
> +
> + return mv88e6xxx_pvt_map(chip, dev, 0);
> +}
> +
> static int mv88e6xxx_port_bridge_join(struct dsa_switch *ds, int port,
> struct dsa_bridge bridge,
> bool *tx_fwd_offload)
> @@ -2468,6 +2481,14 @@ static int mv88e6xxx_port_bridge_join(struct dsa_switch *ds, int port,
> if (err)
> goto unlock;
>
> + if (mv88e6xxx_has_pvt(chip)) {
> + err = mv88e6xxx_map_virtual_bridge_to_pvt(ds, bridge.num);
> + if (err)
> + goto unlock;
> +
> + *tx_fwd_offload = true;
> + }
> +
> unlock:
> mv88e6xxx_reg_unlock(chip);
>
> @@ -2482,6 +2503,10 @@ static void mv88e6xxx_port_bridge_leave(struct dsa_switch *ds, int port,
>
> mv88e6xxx_reg_lock(chip);
>
> + if (bridge.tx_fwd_offload &&
> + mv88e6xxx_map_virtual_bridge_to_pvt(ds, bridge.num))
> + dev_err(ds->dev, "failed to remap cross-chip Port VLAN\n");
I must admit I don't see how this would ever fail in practice. Moreover,
isn't this the exact same call made in port_bridge_join, hence a noop?
Anyway, that seems to have been the case before as well, so it is not
really a problem for your patch series.
> +
> if (mv88e6xxx_bridge_map(chip, bridge) ||
> mv88e6xxx_port_vlan_map(chip, port))
> dev_err(ds->dev, "failed to remap in-chip Port VLAN\n");
> @@ -2527,42 +2552,6 @@ static void mv88e6xxx_crosschip_bridge_leave(struct dsa_switch *ds,
> mv88e6xxx_reg_unlock(chip);
> }
>
> -/* Treat the software bridge as a virtual single-port switch behind the
> - * CPU and map in the PVT. First dst->last_switch elements are taken by
> - * physical switches, so start from beyond that range.
> - */
> -static int mv88e6xxx_map_virtual_bridge_to_pvt(struct dsa_switch *ds,
> - unsigned int bridge_num)
> -{
> - u8 dev = bridge_num + ds->dst->last_switch;
> - struct mv88e6xxx_chip *chip = ds->priv;
> - int err;
> -
> - mv88e6xxx_reg_lock(chip);
> - err = mv88e6xxx_pvt_map(chip, dev, 0);
> - mv88e6xxx_reg_unlock(chip);
> -
> - return err;
> -}
> -
> -static int mv88e6xxx_bridge_tx_fwd_offload(struct dsa_switch *ds, int port,
> - struct dsa_bridge bridge)
> -{
> - return mv88e6xxx_map_virtual_bridge_to_pvt(ds, bridge.num);
> -}
> -
> -static void mv88e6xxx_bridge_tx_fwd_unoffload(struct dsa_switch *ds, int port,
> - struct dsa_bridge bridge)
> -{
> - int err;
> -
> - err = mv88e6xxx_map_virtual_bridge_to_pvt(ds, bridge.num);
> - if (err) {
> - dev_err(ds->dev, "failed to remap cross-chip Port VLAN: %pe\n",
> - ERR_PTR(err));
> - }
> -}
> -
> static int mv88e6xxx_software_reset(struct mv88e6xxx_chip *chip)
> {
> if (chip->info->ops->reset)
> @@ -6282,8 +6271,6 @@ static const struct dsa_switch_ops mv88e6xxx_switch_ops = {
> .crosschip_lag_change = mv88e6xxx_crosschip_lag_change,
> .crosschip_lag_join = mv88e6xxx_crosschip_lag_join,
> .crosschip_lag_leave = mv88e6xxx_crosschip_lag_leave,
> - .port_bridge_tx_fwd_offload = mv88e6xxx_bridge_tx_fwd_offload,
> - .port_bridge_tx_fwd_unoffload = mv88e6xxx_bridge_tx_fwd_unoffload,
> };
>
> static int mv88e6xxx_register_switch(struct mv88e6xxx_chip *chip)
> diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
> index 21622c60faab..cefde41ce8d6 100644
> --- a/drivers/net/dsa/sja1105/sja1105_main.c
> +++ b/drivers/net/dsa/sja1105/sja1105_main.c
> @@ -2077,12 +2077,27 @@ static int sja1105_bridge_join(struct dsa_switch *ds, int port,
> struct dsa_bridge bridge,
> bool *tx_fwd_offload)
> {
> - return sja1105_bridge_member(ds, port, bridge, true);
> + int rc;
> +
> + rc = sja1105_bridge_member(ds, port, bridge, true);
> + if (rc)
> + return rc;
> +
> + rc = dsa_tag_8021q_bridge_tx_fwd_offload(ds, port, bridge);
> + if (rc) {
> + sja1105_bridge_member(ds, port, bridge, false);
> + return rc;
> + }
> +
> + *tx_fwd_offload = true;
> +
> + return 0;
> }
>
> static void sja1105_bridge_leave(struct dsa_switch *ds, int port,
> struct dsa_bridge bridge)
> {
> + dsa_tag_8021q_bridge_tx_fwd_unoffload(ds, port, bridge);
> sja1105_bridge_member(ds, port, bridge, false);
> }
>
> @@ -3231,8 +3246,6 @@ static const struct dsa_switch_ops sja1105_switch_ops = {
> .tag_8021q_vlan_add = sja1105_dsa_8021q_vlan_add,
> .tag_8021q_vlan_del = sja1105_dsa_8021q_vlan_del,
> .port_prechangeupper = sja1105_prechangeupper,
> - .port_bridge_tx_fwd_offload = dsa_tag_8021q_bridge_tx_fwd_offload,
> - .port_bridge_tx_fwd_unoffload = dsa_tag_8021q_bridge_tx_fwd_unoffload,
> };
>
> static const struct of_device_id sja1105_dt_ids[];
> diff --git a/include/net/dsa.h b/include/net/dsa.h
> index 584b3f9462a0..bdf308a5c55e 100644
> --- a/include/net/dsa.h
> +++ b/include/net/dsa.h
> @@ -222,6 +222,7 @@ struct dsa_mall_tc_entry {
> struct dsa_bridge {
> struct net_device *dev;
> unsigned int num;
> + bool tx_fwd_offload;
> refcount_t refcount;
> };
>
> @@ -826,12 +827,6 @@ struct dsa_switch_ops {
> bool *tx_fwd_offload);
> void (*port_bridge_leave)(struct dsa_switch *ds, int port,
> struct dsa_bridge bridge);
> - /* Called right after .port_bridge_join() */
> - int (*port_bridge_tx_fwd_offload)(struct dsa_switch *ds, int port,
> - struct dsa_bridge bridge);
> - /* Called right before .port_bridge_leave() */
> - void (*port_bridge_tx_fwd_unoffload)(struct dsa_switch *ds, int port,
> - struct dsa_bridge bridge);
> void (*port_stp_state_set)(struct dsa_switch *ds, int port,
> u8 state);
> void (*port_fast_age)(struct dsa_switch *ds, int port);
> diff --git a/net/dsa/port.c b/net/dsa/port.c
> index b6c8a1a9ec18..fbe8c054d2b8 100644
> --- a/net/dsa/port.c
> +++ b/net/dsa/port.c
> @@ -270,37 +270,6 @@ static void dsa_port_switchdev_unsync_attrs(struct dsa_port *dp)
> */
> }
>
> -static void dsa_port_bridge_tx_fwd_unoffload(struct dsa_port *dp,
> - struct dsa_bridge bridge)
> -{
> - struct dsa_switch *ds = dp->ds;
> -
> - /* No bridge TX forwarding offload => do nothing */
> - if (!ds->ops->port_bridge_tx_fwd_unoffload || !bridge.num)
> - return;
> -
> - /* Notify the chips only once the offload has been deactivated, so
> - * that they can update their configuration accordingly.
> - */
> - ds->ops->port_bridge_tx_fwd_unoffload(ds, dp->index, bridge);
> -}
> -
> -static bool dsa_port_bridge_tx_fwd_offload(struct dsa_port *dp,
> - struct dsa_bridge bridge)
> -{
> - struct dsa_switch *ds = dp->ds;
> - int err;
> -
> - /* FDB isolation is required for TX forwarding offload */
> - if (!ds->ops->port_bridge_tx_fwd_offload || !bridge.num)
> - return false;
> -
> - /* Notify the driver */
> - err = ds->ops->port_bridge_tx_fwd_offload(ds, dp->index, bridge);
> -
> - return err ? false : true;
> -}
> -
> static int dsa_port_bridge_create(struct dsa_port *dp,
> struct net_device *br,
> struct netlink_ext_ack *extack)
> @@ -361,7 +330,6 @@ int dsa_port_bridge_join(struct dsa_port *dp, struct net_device *br,
> };
> struct net_device *dev = dp->slave;
> struct net_device *brport_dev;
> - bool tx_fwd_offload;
> int err;
>
> /* Here the interface is already bridged. Reflect the current
> @@ -378,12 +346,13 @@ int dsa_port_bridge_join(struct dsa_port *dp, struct net_device *br,
> if (err)
> goto out_rollback;
>
> - tx_fwd_offload = dsa_port_bridge_tx_fwd_offload(dp, info.bridge);
> + /* Drivers which support bridge TX forwarding should set this */
> + dp->bridge->tx_fwd_offload = info.tx_fwd_offload;
>
> err = switchdev_bridge_port_offload(brport_dev, dev, dp,
> &dsa_slave_switchdev_notifier,
> &dsa_slave_switchdev_blocking_notifier,
> - tx_fwd_offload, extack);
> + dp->bridge->tx_fwd_offload, extack);
> if (err)
> goto out_rollback_unbridge;
>
> @@ -434,8 +403,6 @@ void dsa_port_bridge_leave(struct dsa_port *dp, struct net_device *br)
> */
> dsa_port_bridge_destroy(dp, br);
>
> - dsa_port_bridge_tx_fwd_unoffload(dp, info.bridge);
> -
> err = dsa_broadcast(DSA_NOTIFIER_BRIDGE_LEAVE, &info);
> if (err)
> dev_err(dp->ds->dev,
>
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