[PATCH 5.15 110/110] Revert "net: dsa: mv88e6xxx: flush switchdev FDB workqueue before removing VLAN"

Greg Kroah-Hartman
2022-03-14T12:22:41Z

From: Vladimir Oltean <vladimir.oltean@nxp.com>

This reverts commit 2566a89b9e163b2fcd104d6005e0149f197b8a48 which is
commit a2614140dc0f467a83aa3bb4b6ee2d6480a76202 upstream.

The above change depends on upstream commit 0faf890fc519 ("net: dsa:
drop rtnl_lock from dsa_slave_switchdev_event_work"), which is not
present in linux-5.15.y. Without that change, waiting for the switchdev
workqueue causes deadlocks on the rtnl_mutex.

Backporting the dependency commit isn't trivial/desirable, since it
requires that the following dependencies of the dependency are also
backported:

df405910ab9f net: dsa: sja1105: wait for dynamic config command completion on writes too
eb016afd83a9 net: dsa: sja1105: serialize access to the dynamic config interface
2468346c5677 net: mscc: ocelot: serialize access to the MAC table
f7eb4a1c0864 net: dsa: b53: serialize access to the ARL table
cf231b436f7c net: dsa: lantiq_gswip: serialize access to the PCE registers
338a3a4745aa net: dsa: introduce locking for the address lists on CPU and DSA ports

and then this bugfix on top:

8940e6b669ca ("net: dsa: avoid call to __dev_set_promiscuity() while rtnl_mutex isn't held")

Reported-by: Daniel Suchy <danny@danysek.cz>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/dsa/mv88e6xxx/chip.c | 7 -------
include/net/dsa.h | 1 -
net/dsa/dsa.c | 1 -
net/dsa/dsa_priv.h | 1 +
4 files changed, 1 insertion(+), 9 deletions(-)

--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2291,13 +2291,6 @@ static int mv88e6xxx_port_vlan_del(struc
if (!mv88e6xxx_max_vid(chip))
return -EOPNOTSUPP;

- /* The ATU removal procedure needs the FID to be mapped in the VTU,
- * but FDB deletion runs concurrently with VLAN deletion. Flush the DSA
- * switchdev workqueue to ensure that all FDB entries are deleted
- * before we remove the VLAN.
- */
- dsa_flush_workqueue();
-
mv88e6xxx_reg_lock(chip);

err = mv88e6xxx_port_get_pvid(chip, port, &pvid);
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -1056,7 +1056,6 @@ void dsa_unregister_switch(struct dsa_sw
int dsa_register_switch(struct dsa_switch *ds);
void dsa_switch_shutdown(struct dsa_switch *ds);
struct dsa_switch *dsa_switch_find(int tree_index, int sw_index);
-void dsa_flush_workqueue(void);
#ifdef CONFIG_PM_SLEEP
int dsa_switch_suspend(struct dsa_switch *ds);
int dsa_switch_resume(struct dsa_switch *ds);
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -349,7 +349,6 @@ void dsa_flush_workqueue(void)
{
flush_workqueue(dsa_owq);
}
-EXPORT_SYMBOL_GPL(dsa_flush_workqueue);

int dsa_devlink_param_get(struct devlink *dl, u32 id,
struct devlink_param_gset_ctx *ctx)
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -170,6 +170,7 @@ void dsa_tag_driver_put(const struct dsa
const struct dsa_device_ops *dsa_find_tagger_by_name(const char *buf);

bool dsa_schedule_work(struct work_struct *work);
+void dsa_flush_workqueue(void);
const char *dsa_tag_protocol_to_str(const struct dsa_device_ops *ops);

static inline int dsa_tag_protocol_overhead(const struct dsa_device_ops *ops)