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kernel/net/switchdev/switchdev.c
Rasmus Villemoes 20776b465c net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP 
It's not true that switchdev_port_obj_notify() only inspects the
->handled field of "struct switchdev_notifier_port_obj_info" if
call_switchdev_blocking_notifiers() returns 0 - there's a WARN_ON()
triggering for a non-zero return combined with ->handled not being
true. But the real problem here is that -EOPNOTSUPP is not being
properly handled.

The wrapper functions switchdev_handle_port_obj_add() et al change a
return value of -EOPNOTSUPP to 0, and the treatment of ->handled in
switchdev_port_obj_notify() seems to be designed to change that back
to -EOPNOTSUPP in case nobody actually acted on the notifier (i.e.,
everybody returned -EOPNOTSUPP).

Currently, as soon as some device down the stack passes the check_cb()
check, ->handled gets set to true, which means that
switchdev_port_obj_notify() cannot actually ever return -EOPNOTSUPP.

This, for example, means that the detection of hardware offload
support in the MRP code is broken: switchdev_port_obj_add() used by
br_mrp_switchdev_send_ring_test() always returns 0, so since the MRP
code thinks the generation of MRP test frames has been offloaded, no
such frames are actually put on the wire. Similarly,
br_mrp_switchdev_set_ring_role() also always returns 0, causing
mrp->ring_role_offloaded to be set to 1.

To fix this, continue to set ->handled true if any callback returns
success or any error distinct from -EOPNOTSUPP. But if all the
callbacks return -EOPNOTSUPP, make sure that ->handled stays false, so
the logic in switchdev_port_obj_notify() can propagate that
information.

Fixes: 9a9f26e8f7 ("bridge: mrp: Connect MRP API with the switchdev API")
Fixes: f30f0601eb ("switchdev: Add helpers to aid traversal through lower devices")
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Link: https://lore.kernel.org/r/20210125124116.102928-1-rasmus.villemoes@prevas.dk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-01-27 16:41:59 -08:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* net/switchdev/switchdev.c - Switch device API
* Copyright (c) 2014-2015 Jiri Pirko <jiri@resnulli.us>
* Copyright (c) 2014-2015 Scott Feldman <sfeldma@gmail.com>
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/if_bridge.h>
#include <linux/list.h>
#include <linux/workqueue.h>
#include <linux/if_vlan.h>
#include <linux/rtnetlink.h>
#include <net/switchdev.h>
static LIST_HEAD(deferred);
static DEFINE_SPINLOCK(deferred_lock);
typedef void switchdev_deferred_func_t(struct net_device *dev,
const void *data);
struct switchdev_deferred_item {
struct list_head list;
struct net_device *dev;
switchdev_deferred_func_t *func;
unsigned long data[];
};
static struct switchdev_deferred_item *switchdev_deferred_dequeue(void)
{
struct switchdev_deferred_item *dfitem;
spin_lock_bh(&deferred_lock);
if (list_empty(&deferred)) {
dfitem = NULL;
goto unlock;
}
dfitem = list_first_entry(&deferred,
struct switchdev_deferred_item, list);
list_del(&dfitem->list);
unlock:
spin_unlock_bh(&deferred_lock);
return dfitem;
}
/**
* switchdev_deferred_process - Process ops in deferred queue
*
* Called to flush the ops currently queued in deferred ops queue.
* rtnl_lock must be held.
*/
void switchdev_deferred_process(void)
{
struct switchdev_deferred_item *dfitem;
ASSERT_RTNL();
while ((dfitem = switchdev_deferred_dequeue())) {
dfitem->func(dfitem->dev, dfitem->data);
dev_put(dfitem->dev);
kfree(dfitem);
}
}
EXPORT_SYMBOL_GPL(switchdev_deferred_process);
static void switchdev_deferred_process_work(struct work_struct *work)
{
rtnl_lock();
switchdev_deferred_process();
rtnl_unlock();
}
static DECLARE_WORK(deferred_process_work, switchdev_deferred_process_work);
static int switchdev_deferred_enqueue(struct net_device *dev,
const void *data, size_t data_len,
switchdev_deferred_func_t *func)
{
struct switchdev_deferred_item *dfitem;
dfitem = kmalloc(sizeof(*dfitem) + data_len, GFP_ATOMIC);
if (!dfitem)
return -ENOMEM;
dfitem->dev = dev;
dfitem->func = func;
memcpy(dfitem->data, data, data_len);
dev_hold(dev);
spin_lock_bh(&deferred_lock);
list_add_tail(&dfitem->list, &deferred);
spin_unlock_bh(&deferred_lock);
schedule_work(&deferred_process_work);
return 0;
}
static int switchdev_port_attr_notify(enum switchdev_notifier_type nt,
struct net_device *dev,
const struct switchdev_attr *attr,
struct switchdev_trans *trans)
{
int err;
int rc;
struct switchdev_notifier_port_attr_info attr_info = {
.attr = attr,
.trans = trans,
.handled = false,
};
rc = call_switchdev_blocking_notifiers(nt, dev,
&attr_info.info, NULL);
err = notifier_to_errno(rc);
if (err) {
WARN_ON(!attr_info.handled);
return err;
}
if (!attr_info.handled)
return -EOPNOTSUPP;
return 0;
}
static int switchdev_port_attr_set_now(struct net_device *dev,
const struct switchdev_attr *attr)
{
struct switchdev_trans trans;
int err;
/* Phase I: prepare for attr set. Driver/device should fail
* here if there are going to be issues in the commit phase,
* such as lack of resources or support. The driver/device
* should reserve resources needed for the commit phase here,
* but should not commit the attr.
*/
trans.ph_prepare = true;
err = switchdev_port_attr_notify(SWITCHDEV_PORT_ATTR_SET, dev, attr,
&trans);
if (err)
return err;
/* Phase II: commit attr set. This cannot fail as a fault
* of driver/device. If it does, it's a bug in the driver/device
* because the driver said everythings was OK in phase I.
*/
trans.ph_prepare = false;
err = switchdev_port_attr_notify(SWITCHDEV_PORT_ATTR_SET, dev, attr,
&trans);
WARN(err, "%s: Commit of attribute (id=%d) failed.\n",
dev->name, attr->id);
return err;
}
static void switchdev_port_attr_set_deferred(struct net_device *dev,
const void *data)
{
const struct switchdev_attr *attr = data;
int err;
err = switchdev_port_attr_set_now(dev, attr);
if (err && err != -EOPNOTSUPP)
netdev_err(dev, "failed (err=%d) to set attribute (id=%d)\n",
err, attr->id);
if (attr->complete)
attr->complete(dev, err, attr->complete_priv);
}
static int switchdev_port_attr_set_defer(struct net_device *dev,
const struct switchdev_attr *attr)
{
return switchdev_deferred_enqueue(dev, attr, sizeof(*attr),
switchdev_port_attr_set_deferred);
}
/**
* switchdev_port_attr_set - Set port attribute
*
* @dev: port device
* @attr: attribute to set
*
* Use a 2-phase prepare-commit transaction model to ensure
* system is not left in a partially updated state due to
* failure from driver/device.
*
* rtnl_lock must be held and must not be in atomic section,
* in case SWITCHDEV_F_DEFER flag is not set.
*/
int switchdev_port_attr_set(struct net_device *dev,
const struct switchdev_attr *attr)
{
if (attr->flags & SWITCHDEV_F_DEFER)
return switchdev_port_attr_set_defer(dev, attr);
ASSERT_RTNL();
return switchdev_port_attr_set_now(dev, attr);
}
EXPORT_SYMBOL_GPL(switchdev_port_attr_set);
static size_t switchdev_obj_size(const struct switchdev_obj *obj)
{
switch (obj->id) {
case SWITCHDEV_OBJ_ID_PORT_VLAN:
return sizeof(struct switchdev_obj_port_vlan);
case SWITCHDEV_OBJ_ID_PORT_MDB:
return sizeof(struct switchdev_obj_port_mdb);
case SWITCHDEV_OBJ_ID_HOST_MDB:
return sizeof(struct switchdev_obj_port_mdb);
default:
BUG();
}
return 0;
}
static int switchdev_port_obj_notify(enum switchdev_notifier_type nt,
struct net_device *dev,
const struct switchdev_obj *obj,
struct switchdev_trans *trans,
struct netlink_ext_ack *extack)
{
int rc;
int err;
struct switchdev_notifier_port_obj_info obj_info = {
.obj = obj,
.trans = trans,
.handled = false,
};
rc = call_switchdev_blocking_notifiers(nt, dev, &obj_info.info, extack);
err = notifier_to_errno(rc);
if (err) {
WARN_ON(!obj_info.handled);
return err;
}
if (!obj_info.handled)
return -EOPNOTSUPP;
return 0;
}
static int switchdev_port_obj_add_now(struct net_device *dev,
const struct switchdev_obj *obj,
struct netlink_ext_ack *extack)
{
struct switchdev_trans trans;
int err;
ASSERT_RTNL();
/* Phase I: prepare for obj add. Driver/device should fail
* here if there are going to be issues in the commit phase,
* such as lack of resources or support. The driver/device
* should reserve resources needed for the commit phase here,
* but should not commit the obj.
*/
trans.ph_prepare = true;
err = switchdev_port_obj_notify(SWITCHDEV_PORT_OBJ_ADD,
dev, obj, &trans, extack);
if (err)
return err;
/* Phase II: commit obj add. This cannot fail as a fault
* of driver/device. If it does, it's a bug in the driver/device
* because the driver said everythings was OK in phase I.
*/
trans.ph_prepare = false;
err = switchdev_port_obj_notify(SWITCHDEV_PORT_OBJ_ADD,
dev, obj, &trans, extack);
WARN(err, "%s: Commit of object (id=%d) failed.\n", dev->name, obj->id);
return err;
}
static void switchdev_port_obj_add_deferred(struct net_device *dev,
const void *data)
{
const struct switchdev_obj *obj = data;
int err;
err = switchdev_port_obj_add_now(dev, obj, NULL);
if (err && err != -EOPNOTSUPP)
netdev_err(dev, "failed (err=%d) to add object (id=%d)\n",
err, obj->id);
if (obj->complete)
obj->complete(dev, err, obj->complete_priv);
}
static int switchdev_port_obj_add_defer(struct net_device *dev,
const struct switchdev_obj *obj)
{
return switchdev_deferred_enqueue(dev, obj, switchdev_obj_size(obj),
switchdev_port_obj_add_deferred);
}
/**
* switchdev_port_obj_add - Add port object
*
* @dev: port device
* @obj: object to add
* @extack: netlink extended ack
*
* Use a 2-phase prepare-commit transaction model to ensure
* system is not left in a partially updated state due to
* failure from driver/device.
*
* rtnl_lock must be held and must not be in atomic section,
* in case SWITCHDEV_F_DEFER flag is not set.
*/
int switchdev_port_obj_add(struct net_device *dev,
const struct switchdev_obj *obj,
struct netlink_ext_ack *extack)
{
if (obj->flags & SWITCHDEV_F_DEFER)
return switchdev_port_obj_add_defer(dev, obj);
ASSERT_RTNL();
return switchdev_port_obj_add_now(dev, obj, extack);
}
EXPORT_SYMBOL_GPL(switchdev_port_obj_add);
static int switchdev_port_obj_del_now(struct net_device *dev,
const struct switchdev_obj *obj)
{
return switchdev_port_obj_notify(SWITCHDEV_PORT_OBJ_DEL,
dev, obj, NULL, NULL);
}
static void switchdev_port_obj_del_deferred(struct net_device *dev,
const void *data)
{
const struct switchdev_obj *obj = data;
int err;
err = switchdev_port_obj_del_now(dev, obj);
if (err && err != -EOPNOTSUPP)
netdev_err(dev, "failed (err=%d) to del object (id=%d)\n",
err, obj->id);
if (obj->complete)
obj->complete(dev, err, obj->complete_priv);
}
static int switchdev_port_obj_del_defer(struct net_device *dev,
const struct switchdev_obj *obj)
{
return switchdev_deferred_enqueue(dev, obj, switchdev_obj_size(obj),
switchdev_port_obj_del_deferred);
}
/**
* switchdev_port_obj_del - Delete port object
*
* @dev: port device
* @obj: object to delete
*
* rtnl_lock must be held and must not be in atomic section,
* in case SWITCHDEV_F_DEFER flag is not set.
*/
int switchdev_port_obj_del(struct net_device *dev,
const struct switchdev_obj *obj)
{
if (obj->flags & SWITCHDEV_F_DEFER)
return switchdev_port_obj_del_defer(dev, obj);
ASSERT_RTNL();
return switchdev_port_obj_del_now(dev, obj);
}
EXPORT_SYMBOL_GPL(switchdev_port_obj_del);
static ATOMIC_NOTIFIER_HEAD(switchdev_notif_chain);
static BLOCKING_NOTIFIER_HEAD(switchdev_blocking_notif_chain);
/**
* register_switchdev_notifier - Register notifier
* @nb: notifier_block
*
* Register switch device notifier.
*/
int register_switchdev_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_register(&switchdev_notif_chain, nb);
}
EXPORT_SYMBOL_GPL(register_switchdev_notifier);
/**
* unregister_switchdev_notifier - Unregister notifier
* @nb: notifier_block
*
* Unregister switch device notifier.
*/
int unregister_switchdev_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_unregister(&switchdev_notif_chain, nb);
}
EXPORT_SYMBOL_GPL(unregister_switchdev_notifier);
/**
* call_switchdev_notifiers - Call notifiers
* @val: value passed unmodified to notifier function
* @dev: port device
* @info: notifier information data
* @extack: netlink extended ack
* Call all network notifier blocks.
*/
int call_switchdev_notifiers(unsigned long val, struct net_device *dev,
struct switchdev_notifier_info *info,
struct netlink_ext_ack *extack)
{
info->dev = dev;
info->extack = extack;
return atomic_notifier_call_chain(&switchdev_notif_chain, val, info);
}
EXPORT_SYMBOL_GPL(call_switchdev_notifiers);
int register_switchdev_blocking_notifier(struct notifier_block *nb)
{
struct blocking_notifier_head *chain = &switchdev_blocking_notif_chain;
return blocking_notifier_chain_register(chain, nb);
}
EXPORT_SYMBOL_GPL(register_switchdev_blocking_notifier);
int unregister_switchdev_blocking_notifier(struct notifier_block *nb)
{
struct blocking_notifier_head *chain = &switchdev_blocking_notif_chain;
return blocking_notifier_chain_unregister(chain, nb);
}
EXPORT_SYMBOL_GPL(unregister_switchdev_blocking_notifier);
int call_switchdev_blocking_notifiers(unsigned long val, struct net_device *dev,
struct switchdev_notifier_info *info,
struct netlink_ext_ack *extack)
{
info->dev = dev;
info->extack = extack;
return blocking_notifier_call_chain(&switchdev_blocking_notif_chain,
val, info);
}
EXPORT_SYMBOL_GPL(call_switchdev_blocking_notifiers);
static int __switchdev_handle_port_obj_add(struct net_device *dev,
struct switchdev_notifier_port_obj_info *port_obj_info,
bool (*check_cb)(const struct net_device *dev),
int (*add_cb)(struct net_device *dev,
const struct switchdev_obj *obj,
struct switchdev_trans *trans,
struct netlink_ext_ack *extack))
{
struct netlink_ext_ack *extack;
struct net_device *lower_dev;
struct list_head *iter;
int err = -EOPNOTSUPP;
extack = switchdev_notifier_info_to_extack(&port_obj_info->info);
if (check_cb(dev)) {
err = add_cb(dev, port_obj_info->obj, port_obj_info->trans,
extack);
if (err != -EOPNOTSUPP)
port_obj_info->handled = true;
return err;
}
/* Switch ports might be stacked under e.g. a LAG. Ignore the
* unsupported devices, another driver might be able to handle them. But
* propagate to the callers any hard errors.
*
* If the driver does its own bookkeeping of stacked ports, it's not
* necessary to go through this helper.
*/
netdev_for_each_lower_dev(dev, lower_dev, iter) {
if (netif_is_bridge_master(lower_dev))
continue;
err = __switchdev_handle_port_obj_add(lower_dev, port_obj_info,
check_cb, add_cb);
if (err && err != -EOPNOTSUPP)
return err;
}
return err;
}
int switchdev_handle_port_obj_add(struct net_device *dev,
struct switchdev_notifier_port_obj_info *port_obj_info,
bool (*check_cb)(const struct net_device *dev),
int (*add_cb)(struct net_device *dev,
const struct switchdev_obj *obj,
struct switchdev_trans *trans,
struct netlink_ext_ack *extack))
{
int err;
err = __switchdev_handle_port_obj_add(dev, port_obj_info, check_cb,
add_cb);
if (err == -EOPNOTSUPP)
err = 0;
return err;
}
EXPORT_SYMBOL_GPL(switchdev_handle_port_obj_add);
static int __switchdev_handle_port_obj_del(struct net_device *dev,
struct switchdev_notifier_port_obj_info *port_obj_info,
bool (*check_cb)(const struct net_device *dev),
int (*del_cb)(struct net_device *dev,
const struct switchdev_obj *obj))
{
struct net_device *lower_dev;
struct list_head *iter;
int err = -EOPNOTSUPP;
if (check_cb(dev)) {
err = del_cb(dev, port_obj_info->obj);
if (err != -EOPNOTSUPP)
port_obj_info->handled = true;
return err;
}
/* Switch ports might be stacked under e.g. a LAG. Ignore the
* unsupported devices, another driver might be able to handle them. But
* propagate to the callers any hard errors.
*
* If the driver does its own bookkeeping of stacked ports, it's not
* necessary to go through this helper.
*/
netdev_for_each_lower_dev(dev, lower_dev, iter) {
if (netif_is_bridge_master(lower_dev))
continue;
err = __switchdev_handle_port_obj_del(lower_dev, port_obj_info,
check_cb, del_cb);
if (err && err != -EOPNOTSUPP)
return err;
}
return err;
}
int switchdev_handle_port_obj_del(struct net_device *dev,
struct switchdev_notifier_port_obj_info *port_obj_info,
bool (*check_cb)(const struct net_device *dev),
int (*del_cb)(struct net_device *dev,
const struct switchdev_obj *obj))
{
int err;
err = __switchdev_handle_port_obj_del(dev, port_obj_info, check_cb,
del_cb);
if (err == -EOPNOTSUPP)
err = 0;
return err;
}
EXPORT_SYMBOL_GPL(switchdev_handle_port_obj_del);
static int __switchdev_handle_port_attr_set(struct net_device *dev,
struct switchdev_notifier_port_attr_info *port_attr_info,
bool (*check_cb)(const struct net_device *dev),
int (*set_cb)(struct net_device *dev,
const struct switchdev_attr *attr,
struct switchdev_trans *trans))
{
struct net_device *lower_dev;
struct list_head *iter;
int err = -EOPNOTSUPP;
if (check_cb(dev)) {
err = set_cb(dev, port_attr_info->attr, port_attr_info->trans);
if (err != -EOPNOTSUPP)
port_attr_info->handled = true;
return err;
}
/* Switch ports might be stacked under e.g. a LAG. Ignore the
* unsupported devices, another driver might be able to handle them. But
* propagate to the callers any hard errors.
*
* If the driver does its own bookkeeping of stacked ports, it's not
* necessary to go through this helper.
*/
netdev_for_each_lower_dev(dev, lower_dev, iter) {
if (netif_is_bridge_master(lower_dev))
continue;
err = __switchdev_handle_port_attr_set(lower_dev, port_attr_info,
check_cb, set_cb);
if (err && err != -EOPNOTSUPP)
return err;
}
return err;
}
int switchdev_handle_port_attr_set(struct net_device *dev,
struct switchdev_notifier_port_attr_info *port_attr_info,
bool (*check_cb)(const struct net_device *dev),
int (*set_cb)(struct net_device *dev,
const struct switchdev_attr *attr,
struct switchdev_trans *trans))
{
int err;
err = __switchdev_handle_port_attr_set(dev, port_attr_info, check_cb,
set_cb);
if (err == -EOPNOTSUPP)
err = 0;
return err;
}
EXPORT_SYMBOL_GPL(switchdev_handle_port_attr_set);
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