doc: update switchdev L3 section

This is to reflect the change of FIB offload infrastructure from
switchdev objects to FIB notifier.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Reviewed-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/networking/switchdev.txt

@@ -314,30 +314,29 @@ the kernel, with the device doing the FIB lookup and forwarding.  The device
 does a longest prefix match (LPM) on FIB entries matching route prefix and
 forwards the packet to the matching FIB entry's nexthop(s) egress ports.
 
-To program the device, the driver implements support for
-SWITCHDEV_OBJ_IPV[4|6]_FIB object using switchdev_port_obj_xxx ops.
-switchdev_port_obj_add is used for both adding a new FIB entry to the device,
-or modifying an existing entry on the device.
+To program the device, the driver has to register a FIB notifier handler
+using register_fib_notifier. The following events are available:
+FIB_EVENT_ENTRY_ADD: used for both adding a new FIB entry to the device,
+                     or modifying an existing entry on the device.
+FIB_EVENT_ENTRY_DEL: used for removing a FIB entry
+FIB_EVENT_RULE_ADD, FIB_EVENT_RULE_DEL: used to propagate FIB rule changes
 
-XXX: Currently, only SWITCHDEV_OBJ_ID_IPV4_FIB objects are supported.
+FIB_EVENT_ENTRY_ADD and FIB_EVENT_ENTRY_DEL events pass:
 
-SWITCHDEV_OBJ_ID_IPV4_FIB object passes:
-
-	struct switchdev_obj_ipv4_fib {         /* IPV4_FIB */
+	struct fib_entry_notifier_info {
+		struct fib_notifier_info info; /* must be first */
 		u32 dst;
 		int dst_len;
 		struct fib_info *fi;
 		u8 tos;
 		u8 type;
-		u32 nlflags;
 		u32 tb_id;
-	} ipv4_fib;
+		u32 nlflags;
+	};
 
 to add/modify/delete IPv4 dst/dest_len prefix on table tb_id.  The *fi
 structure holds details on the route and route's nexthops.  *dev is one of the
-port netdevs mentioned in the routes next hop list.  If the output port netdevs
-referenced in the route's nexthop list don't all have the same switch ID, the
-driver is not called to add/modify/delete the FIB entry.
+port netdevs mentioned in the route's next hop list.
 
 Routes offloaded to the device are labeled with "offload" in the ip route
 listing:
@@ -355,6 +354,8 @@ listing:
 	12.0.0.4 via 11.0.0.9 dev sw1p2  proto zebra  metric 20 offload
 	192.168.0.0/24 dev eth0  proto kernel  scope link  src 192.168.0.15
 
+The "offload" flag is set in case at least one device offloads the FIB entry.
+
 XXX: add/mod/del IPv6 FIB API
 
 Nexthop Resolution