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linux-stable/include/net/switchdev.h
Vladimir Oltean 957e2235e5 net: make switchdev_bridge_port_{,unoffload} loosely coupled with the bridge 
With the introduction of explicit offloading API in switchdev in commit
2f5dc00f7a ("net: bridge: switchdev: let drivers inform which bridge
ports are offloaded"), we started having Ethernet switch drivers calling
directly into a function exported by net/bridge/br_switchdev.c, which is
a function exported by the bridge driver.

This means that drivers that did not have an explicit dependency on the
bridge before, like cpsw and am65-cpsw, now do - otherwise it is not
possible to call a symbol exported by a driver that can be built as
module unless you are a module too.

There was an attempt to solve the dependency issue in the form of commit
b0e8181762 ("net: build all switchdev drivers as modules when the
bridge is a module"). Grygorii Strashko, however, says about it:

| In my opinion, the problem is a bit bigger here than just fixing the
| build :(
|
| In case, of ^cpsw the switchdev mode is kinda optional and in many
| cases (especially for testing purposes, NFS) the multi-mac mode is
| still preferable mode.
|
| There were no such tight dependency between switchdev drivers and
| bridge core before and switchdev serviced as independent, notification
| based layer between them, so ^cpsw still can be "Y" and bridge can be
| "M". Now for mostly every kernel build configuration the CONFIG_BRIDGE
| will need to be set as "Y", or we will have to update drivers to
| support build with BRIDGE=n and maintain separate builds for
| networking vs non-networking testing.  But is this enough?  Wouldn't
| it cause 'chain reaction' required to add more and more "Y" options
| (like CONFIG_VLAN_8021Q)?
|
| PS. Just to be sure we on the same page - ARM builds will be forced
| (with this patch) to have CONFIG_TI_CPSW_SWITCHDEV=m and so all our
| automation testing will just fail with omap2plus_defconfig.

In the light of this, it would be desirable for some configurations to
avoid dependencies between switchdev drivers and the bridge, and have
the switchdev mode as completely optional within the driver.

Arnd Bergmann also tried to write a patch which better expressed the
build time dependency for Ethernet switch drivers where the switchdev
support is optional, like cpsw/am65-cpsw, and this made the drivers
follow the bridge (compile as module if the bridge is a module) only if
the optional switchdev support in the driver was enabled in the first
place:
https://patchwork.kernel.org/project/netdevbpf/patch/20210802144813.1152762-1-arnd@kernel.org/

but this still did not solve the fact that cpsw and am65-cpsw now must
be built as modules when the bridge is a module - it just expressed
correctly that optional dependency. But the new behavior is an apparent
regression from Grygorii's perspective.

So to support the use case where the Ethernet driver is built-in,
NET_SWITCHDEV (a bool option) is enabled, and the bridge is a module, we
need a framework that can handle the possible absence of the bridge from
the running system, i.e. runtime bloatware as opposed to build-time
bloatware.

Luckily we already have this framework, since switchdev has been using
it extensively. Events from the bridge side are transmitted to the
driver side using notifier chains - this was originally done so that
unrelated drivers could snoop for events emitted by the bridge towards
ports that are implemented by other drivers (think of a switch driver
with LAG offload that listens for switchdev events on a bonding/team
interface that it offloads).

There are also events which are transmitted from the driver side to the
bridge side, which again are modeled using notifiers.
SWITCHDEV_FDB_ADD_TO_BRIDGE is an example of this, and deals with
notifying the bridge that a MAC address has been dynamically learned.
So there is a precedent we can use for modeling the new framework.

The difference compared to SWITCHDEV_FDB_ADD_TO_BRIDGE is that the work
that the bridge needs to do when a port becomes offloaded is blocking in
its nature: replay VLANs, MDBs etc. The calling context is indeed
blocking (we are under rtnl_mutex), but the existing switchdev
notification chain that the bridge is subscribed to is only the atomic
one. So we need to subscribe the bridge to the blocking switchdev
notification chain too.

This patch:
- keeps the driver-side perception of the switchdev_bridge_port_{,un}offload
  unchanged
- moves the implementation of switchdev_bridge_port_{,un}offload from
  the bridge module into the switchdev module.
- makes everybody that is subscribed to the switchdev blocking notifier
  chain "hear" offload & unoffload events
- makes the bridge driver subscribe and handle those events
- moves the bridge driver's handling of those events into 2 new
  functions called br_switchdev_port_{,un}offload. These functions
  contain in fact the core of the logic that was previously in
  switchdev_bridge_port_{,un}offload, just that now we go through an
  extra indirection layer to reach them.

Unlike all the other switchdev notification structures, the structure
used to carry the bridge port information, struct
switchdev_notifier_brport_info, does not contain a "bool handled".
This is because in the current usage pattern, we always know that a
switchdev bridge port offloading event will be handled by the bridge,
because the switchdev_bridge_port_offload() call was initiated by a
NETDEV_CHANGEUPPER event in the first place, where info->upper_dev is a
bridge. So if the bridge wasn't loaded, then the CHANGEUPPER event
couldn't have happened.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-04 12:35:07 +01:00

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* include/net/switchdev.h - Switch device API
* Copyright (c) 2014-2015 Jiri Pirko <jiri@resnulli.us>
* Copyright (c) 2014-2015 Scott Feldman <sfeldma@gmail.com>
*/
#ifndef _LINUX_SWITCHDEV_H_
#define _LINUX_SWITCHDEV_H_
#include <linux/netdevice.h>
#include <linux/notifier.h>
#include <linux/list.h>
#include <net/ip_fib.h>
#define SWITCHDEV_F_NO_RECURSE BIT(0)
#define SWITCHDEV_F_SKIP_EOPNOTSUPP BIT(1)
#define SWITCHDEV_F_DEFER BIT(2)
enum switchdev_attr_id {
SWITCHDEV_ATTR_ID_UNDEFINED,
SWITCHDEV_ATTR_ID_PORT_STP_STATE,
SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS,
SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS,
SWITCHDEV_ATTR_ID_PORT_MROUTER,
SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME,
SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING,
SWITCHDEV_ATTR_ID_BRIDGE_VLAN_PROTOCOL,
SWITCHDEV_ATTR_ID_BRIDGE_MC_DISABLED,
SWITCHDEV_ATTR_ID_BRIDGE_MROUTER,
SWITCHDEV_ATTR_ID_MRP_PORT_ROLE,
};
struct switchdev_brport_flags {
unsigned long val;
unsigned long mask;
};
struct switchdev_attr {
struct net_device *orig_dev;
enum switchdev_attr_id id;
u32 flags;
void *complete_priv;
void (*complete)(struct net_device *dev, int err, void *priv);
union {
u8 stp_state; /* PORT_STP_STATE */
struct switchdev_brport_flags brport_flags; /* PORT_BRIDGE_FLAGS */
bool mrouter; /* PORT_MROUTER */
clock_t ageing_time; /* BRIDGE_AGEING_TIME */
bool vlan_filtering; /* BRIDGE_VLAN_FILTERING */
u16 vlan_protocol; /* BRIDGE_VLAN_PROTOCOL */
bool mc_disabled; /* MC_DISABLED */
u8 mrp_port_role; /* MRP_PORT_ROLE */
} u;
};
enum switchdev_obj_id {
SWITCHDEV_OBJ_ID_UNDEFINED,
SWITCHDEV_OBJ_ID_PORT_VLAN,
SWITCHDEV_OBJ_ID_PORT_MDB,
SWITCHDEV_OBJ_ID_HOST_MDB,
SWITCHDEV_OBJ_ID_MRP,
SWITCHDEV_OBJ_ID_RING_TEST_MRP,
SWITCHDEV_OBJ_ID_RING_ROLE_MRP,
SWITCHDEV_OBJ_ID_RING_STATE_MRP,
SWITCHDEV_OBJ_ID_IN_TEST_MRP,
SWITCHDEV_OBJ_ID_IN_ROLE_MRP,
SWITCHDEV_OBJ_ID_IN_STATE_MRP,
};
struct switchdev_obj {
struct list_head list;
struct net_device *orig_dev;
enum switchdev_obj_id id;
u32 flags;
void *complete_priv;
void (*complete)(struct net_device *dev, int err, void *priv);
};
/* SWITCHDEV_OBJ_ID_PORT_VLAN */
struct switchdev_obj_port_vlan {
struct switchdev_obj obj;
u16 flags;
u16 vid;
};
#define SWITCHDEV_OBJ_PORT_VLAN(OBJ) \
container_of((OBJ), struct switchdev_obj_port_vlan, obj)
/* SWITCHDEV_OBJ_ID_PORT_MDB */
struct switchdev_obj_port_mdb {
struct switchdev_obj obj;
unsigned char addr[ETH_ALEN];
u16 vid;
};
#define SWITCHDEV_OBJ_PORT_MDB(OBJ) \
container_of((OBJ), struct switchdev_obj_port_mdb, obj)
/* SWITCHDEV_OBJ_ID_MRP */
struct switchdev_obj_mrp {
struct switchdev_obj obj;
struct net_device *p_port;
struct net_device *s_port;
u32 ring_id;
u16 prio;
};
#define SWITCHDEV_OBJ_MRP(OBJ) \
container_of((OBJ), struct switchdev_obj_mrp, obj)
/* SWITCHDEV_OBJ_ID_RING_TEST_MRP */
struct switchdev_obj_ring_test_mrp {
struct switchdev_obj obj;
/* The value is in us and a value of 0 represents to stop */
u32 interval;
u8 max_miss;
u32 ring_id;
u32 period;
bool monitor;
};
#define SWITCHDEV_OBJ_RING_TEST_MRP(OBJ) \
container_of((OBJ), struct switchdev_obj_ring_test_mrp, obj)
/* SWICHDEV_OBJ_ID_RING_ROLE_MRP */
struct switchdev_obj_ring_role_mrp {
struct switchdev_obj obj;
u8 ring_role;
u32 ring_id;
u8 sw_backup;
};
#define SWITCHDEV_OBJ_RING_ROLE_MRP(OBJ) \
container_of((OBJ), struct switchdev_obj_ring_role_mrp, obj)
struct switchdev_obj_ring_state_mrp {
struct switchdev_obj obj;
u8 ring_state;
u32 ring_id;
};
#define SWITCHDEV_OBJ_RING_STATE_MRP(OBJ) \
container_of((OBJ), struct switchdev_obj_ring_state_mrp, obj)
/* SWITCHDEV_OBJ_ID_IN_TEST_MRP */
struct switchdev_obj_in_test_mrp {
struct switchdev_obj obj;
/* The value is in us and a value of 0 represents to stop */
u32 interval;
u32 in_id;
u32 period;
u8 max_miss;
};
#define SWITCHDEV_OBJ_IN_TEST_MRP(OBJ) \
container_of((OBJ), struct switchdev_obj_in_test_mrp, obj)
/* SWICHDEV_OBJ_ID_IN_ROLE_MRP */
struct switchdev_obj_in_role_mrp {
struct switchdev_obj obj;
struct net_device *i_port;
u32 ring_id;
u16 in_id;
u8 in_role;
u8 sw_backup;
};
#define SWITCHDEV_OBJ_IN_ROLE_MRP(OBJ) \
container_of((OBJ), struct switchdev_obj_in_role_mrp, obj)
struct switchdev_obj_in_state_mrp {
struct switchdev_obj obj;
u32 in_id;
u8 in_state;
};
#define SWITCHDEV_OBJ_IN_STATE_MRP(OBJ) \
container_of((OBJ), struct switchdev_obj_in_state_mrp, obj)
typedef int switchdev_obj_dump_cb_t(struct switchdev_obj *obj);
struct switchdev_brport {
struct net_device *dev;
const void *ctx;
struct notifier_block *atomic_nb;
struct notifier_block *blocking_nb;
bool tx_fwd_offload;
};
enum switchdev_notifier_type {
SWITCHDEV_FDB_ADD_TO_BRIDGE = 1,
SWITCHDEV_FDB_DEL_TO_BRIDGE,
SWITCHDEV_FDB_ADD_TO_DEVICE,
SWITCHDEV_FDB_DEL_TO_DEVICE,
SWITCHDEV_FDB_OFFLOADED,
SWITCHDEV_FDB_FLUSH_TO_BRIDGE,
SWITCHDEV_PORT_OBJ_ADD, /* Blocking. */
SWITCHDEV_PORT_OBJ_DEL, /* Blocking. */
SWITCHDEV_PORT_ATTR_SET, /* May be blocking . */
SWITCHDEV_VXLAN_FDB_ADD_TO_BRIDGE,
SWITCHDEV_VXLAN_FDB_DEL_TO_BRIDGE,
SWITCHDEV_VXLAN_FDB_ADD_TO_DEVICE,
SWITCHDEV_VXLAN_FDB_DEL_TO_DEVICE,
SWITCHDEV_VXLAN_FDB_OFFLOADED,
SWITCHDEV_BRPORT_OFFLOADED,
SWITCHDEV_BRPORT_UNOFFLOADED,
};
struct switchdev_notifier_info {
struct net_device *dev;
struct netlink_ext_ack *extack;
const void *ctx;
};
struct switchdev_notifier_fdb_info {
struct switchdev_notifier_info info; /* must be first */
const unsigned char *addr;
u16 vid;
u8 added_by_user:1,
is_local:1,
offloaded:1;
};
struct switchdev_notifier_port_obj_info {
struct switchdev_notifier_info info; /* must be first */
const struct switchdev_obj *obj;
bool handled;
};
struct switchdev_notifier_port_attr_info {
struct switchdev_notifier_info info; /* must be first */
const struct switchdev_attr *attr;
bool handled;
};
struct switchdev_notifier_brport_info {
struct switchdev_notifier_info info; /* must be first */
const struct switchdev_brport brport;
};
static inline struct net_device *
switchdev_notifier_info_to_dev(const struct switchdev_notifier_info *info)
{
return info->dev;
}
static inline struct netlink_ext_ack *
switchdev_notifier_info_to_extack(const struct switchdev_notifier_info *info)
{
return info->extack;
}
static inline bool
switchdev_fdb_is_dynamically_learned(const struct switchdev_notifier_fdb_info *fdb_info)
{
return !fdb_info->added_by_user && !fdb_info->is_local;
}
#ifdef CONFIG_NET_SWITCHDEV
int switchdev_bridge_port_offload(struct net_device *brport_dev,
struct net_device *dev, const void *ctx,
struct notifier_block *atomic_nb,
struct notifier_block *blocking_nb,
bool tx_fwd_offload,
struct netlink_ext_ack *extack);
void switchdev_bridge_port_unoffload(struct net_device *brport_dev,
const void *ctx,
struct notifier_block *atomic_nb,
struct notifier_block *blocking_nb);
void switchdev_deferred_process(void);
int switchdev_port_attr_set(struct net_device *dev,
const struct switchdev_attr *attr,
struct netlink_ext_ack *extack);
int switchdev_port_obj_add(struct net_device *dev,
const struct switchdev_obj *obj,
struct netlink_ext_ack *extack);
int switchdev_port_obj_del(struct net_device *dev,
const struct switchdev_obj *obj);
int register_switchdev_notifier(struct notifier_block *nb);
int unregister_switchdev_notifier(struct notifier_block *nb);
int call_switchdev_notifiers(unsigned long val, struct net_device *dev,
struct switchdev_notifier_info *info,
struct netlink_ext_ack *extack);
int register_switchdev_blocking_notifier(struct notifier_block *nb);
int unregister_switchdev_blocking_notifier(struct notifier_block *nb);
int call_switchdev_blocking_notifiers(unsigned long val, struct net_device *dev,
struct switchdev_notifier_info *info,
struct netlink_ext_ack *extack);
void switchdev_port_fwd_mark_set(struct net_device *dev,
struct net_device *group_dev,
bool joining);
int switchdev_handle_fdb_add_to_device(struct net_device *dev,
const struct switchdev_notifier_fdb_info *fdb_info,
bool (*check_cb)(const struct net_device *dev),
bool (*foreign_dev_check_cb)(const struct net_device *dev,
const struct net_device *foreign_dev),
int (*add_cb)(struct net_device *dev,
const struct net_device *orig_dev, const void *ctx,
const struct switchdev_notifier_fdb_info *fdb_info),
int (*lag_add_cb)(struct net_device *dev,
const struct net_device *orig_dev, const void *ctx,
const struct switchdev_notifier_fdb_info *fdb_info));
int switchdev_handle_fdb_del_to_device(struct net_device *dev,
const struct switchdev_notifier_fdb_info *fdb_info,
bool (*check_cb)(const struct net_device *dev),
bool (*foreign_dev_check_cb)(const struct net_device *dev,
const struct net_device *foreign_dev),
int (*del_cb)(struct net_device *dev,
const struct net_device *orig_dev, const void *ctx,
const struct switchdev_notifier_fdb_info *fdb_info),
int (*lag_del_cb)(struct net_device *dev,
const struct net_device *orig_dev, const void *ctx,
const struct switchdev_notifier_fdb_info *fdb_info));
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 void *ctx,
const struct switchdev_obj *obj,
struct netlink_ext_ack *extack));
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 void *ctx,
const struct switchdev_obj *obj));
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 void *ctx,
const struct switchdev_attr *attr,
struct netlink_ext_ack *extack));
#else
static inline int
switchdev_bridge_port_offload(struct net_device *brport_dev,
struct net_device *dev, const void *ctx,
struct notifier_block *atomic_nb,
struct notifier_block *blocking_nb,
bool tx_fwd_offload,
struct netlink_ext_ack *extack)
{
return -EOPNOTSUPP;
}
static inline void
switchdev_bridge_port_unoffload(struct net_device *brport_dev,
const void *ctx,
struct notifier_block *atomic_nb,
struct notifier_block *blocking_nb)
{
}
static inline void switchdev_deferred_process(void)
{
}
static inline int switchdev_port_attr_set(struct net_device *dev,
const struct switchdev_attr *attr,
struct netlink_ext_ack *extack)
{
return -EOPNOTSUPP;
}
static inline int switchdev_port_obj_add(struct net_device *dev,
const struct switchdev_obj *obj,
struct netlink_ext_ack *extack)
{
return -EOPNOTSUPP;
}
static inline int switchdev_port_obj_del(struct net_device *dev,
const struct switchdev_obj *obj)
{
return -EOPNOTSUPP;
}
static inline int register_switchdev_notifier(struct notifier_block *nb)
{
return 0;
}
static inline int unregister_switchdev_notifier(struct notifier_block *nb)
{
return 0;
}
static inline int call_switchdev_notifiers(unsigned long val,
struct net_device *dev,
struct switchdev_notifier_info *info,
struct netlink_ext_ack *extack)
{
return NOTIFY_DONE;
}
static inline int
register_switchdev_blocking_notifier(struct notifier_block *nb)
{
return 0;
}
static inline int
unregister_switchdev_blocking_notifier(struct notifier_block *nb)
{
return 0;
}
static inline int
call_switchdev_blocking_notifiers(unsigned long val,
struct net_device *dev,
struct switchdev_notifier_info *info,
struct netlink_ext_ack *extack)
{
return NOTIFY_DONE;
}
static inline int
switchdev_handle_fdb_add_to_device(struct net_device *dev,
const struct switchdev_notifier_fdb_info *fdb_info,
bool (*check_cb)(const struct net_device *dev),
bool (*foreign_dev_check_cb)(const struct net_device *dev,
const struct net_device *foreign_dev),
int (*add_cb)(struct net_device *dev,
const struct net_device *orig_dev, const void *ctx,
const struct switchdev_notifier_fdb_info *fdb_info),
int (*lag_add_cb)(struct net_device *dev,
const struct net_device *orig_dev, const void *ctx,
const struct switchdev_notifier_fdb_info *fdb_info))
{
return 0;
}
static inline int
switchdev_handle_fdb_del_to_device(struct net_device *dev,
const struct switchdev_notifier_fdb_info *fdb_info,
bool (*check_cb)(const struct net_device *dev),
bool (*foreign_dev_check_cb)(const struct net_device *dev,
const struct net_device *foreign_dev),
int (*del_cb)(struct net_device *dev,
const struct net_device *orig_dev, const void *ctx,
const struct switchdev_notifier_fdb_info *fdb_info),
int (*lag_del_cb)(struct net_device *dev,
const struct net_device *orig_dev, const void *ctx,
const struct switchdev_notifier_fdb_info *fdb_info))
{
return 0;
}
static inline 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 void *ctx,
const struct switchdev_obj *obj,
struct netlink_ext_ack *extack))
{
return 0;
}
static inline 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 void *ctx,
const struct switchdev_obj *obj))
{
return 0;
}
static inline 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 void *ctx,
const struct switchdev_attr *attr,
struct netlink_ext_ack *extack))
{
return 0;
}
#endif
#endif /* _LINUX_SWITCHDEV_H_ */
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