[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20141119134645.GE1926@nanopsycho.orion>
Date: Wed, 19 Nov 2014 14:46:45 +0100
From: Jiri Pirko <jiri@...nulli.us>
To: Roopa Prabhu <roopa@...ulusnetworks.com>
Cc: netdev@...r.kernel.org, davem@...emloft.net, nhorman@...driver.com,
andy@...yhouse.net, tgraf@...g.ch, dborkman@...hat.com,
ogerlitz@...lanox.com, jesse@...ira.com, pshelar@...ira.com,
azhou@...ira.com, ben@...adent.org.uk, stephen@...workplumber.org,
jeffrey.t.kirsher@...el.com, vyasevic@...hat.com,
xiyou.wangcong@...il.com, john.r.fastabend@...el.com,
edumazet@...gle.com, jhs@...atatu.com, sfeldma@...il.com,
f.fainelli@...il.com, linville@...driver.com, jasowang@...hat.com,
ebiederm@...ssion.com, nicolas.dichtel@...nd.com,
ryazanov.s.a@...il.com, buytenh@...tstofly.org,
aviadr@...lanox.com, nbd@...nwrt.org, alexei.starovoitov@...il.com,
Neil.Jerram@...aswitch.com, ronye@...lanox.com,
simon.horman@...ronome.com, alexander.h.duyck@...hat.com,
john.ronciak@...el.com, mleitner@...hat.com, shrijeet@...il.com,
gospo@...ulusnetworks.com, bcrl@...ck.org
Subject: Re: [patch net-next v2 02/10] net: introduce generic switch devices
support
Wed, Nov 19, 2014 at 02:28:10PM CET, roopa@...ulusnetworks.com wrote:
>On 11/9/14, 2:51 AM, Jiri Pirko wrote:
>>The goal of this is to provide a possibility to support various switch
>>chips. Drivers should implement relevant ndos to do so. Now there is
>>only one ndo defined:
>>- for getting physical switch id is in place.
>>
>>Note that user can use random port netdevice to access the switch.
>>
>>Signed-off-by: Jiri Pirko <jiri@...nulli.us>
>>---
>> Documentation/networking/switchdev.txt | 59 ++++++++++++++++++++++++++++++++++
>> MAINTAINERS | 7 ++++
>> include/linux/netdevice.h | 10 ++++++
>> include/net/switchdev.h | 30 +++++++++++++++++
>> net/Kconfig | 1 +
>> net/Makefile | 3 ++
>> net/switchdev/Kconfig | 13 ++++++++
>> net/switchdev/Makefile | 5 +++
>> net/switchdev/switchdev.c | 33 +++++++++++++++++++
>> 9 files changed, 161 insertions(+)
>> create mode 100644 Documentation/networking/switchdev.txt
>> create mode 100644 include/net/switchdev.h
>> create mode 100644 net/switchdev/Kconfig
>> create mode 100644 net/switchdev/Makefile
>> create mode 100644 net/switchdev/switchdev.c
>>
>>diff --git a/Documentation/networking/switchdev.txt b/Documentation/networking/switchdev.txt
>>new file mode 100644
>>index 0000000..98be76c
>>--- /dev/null
>>+++ b/Documentation/networking/switchdev.txt
>>@@ -0,0 +1,59 @@
>>+Switch (and switch-ish) device drivers HOWTO
>>+===========================
>>+
>>+Please note that the word "switch" is here used in very generic meaning.
>>+This include devices supporting L2/L3 but also various flow offloading chips,
>>+including switches embedded into SR-IOV NICs.
>>+
>>+Lets describe a topology a bit. Imagine the following example:
>>+
>>+ +----------------------------+ +---------------+
>>+ | SOME switch chip | | CPU |
>>+ +----------------------------+ +---------------+
>>+ port1 port2 port3 port4 MNGMNT | PCI-E |
>>+ | | | | | +---------------+
>>+ PHY PHY | | | | NIC0 NIC1
>>+ | | | | | |
>>+ | | +- PCI-E -+ | |
>>+ | +------- MII -------+ |
>>+ +------------- MII ------------+
>>+
>>+In this example, there are two independent lines between the switch silicon
>>+and CPU. NIC0 and NIC1 drivers are not aware of a switch presence. They are
>>+separate from the switch driver. SOME switch chip is by managed by a driver
>>+via PCI-E device MNGMNT. Note that MNGMNT device, NIC0 and NIC1 may be
>>+connected to some other type of bus.
>>+
>>+Now, for the previous example show the representation in kernel:
>>+
>>+ +----------------------------+ +---------------+
>>+ | SOME switch chip | | CPU |
>>+ +----------------------------+ +---------------+
>>+ sw0p0 sw0p1 sw0p2 sw0p3 MNGMNT | PCI-E |
>>+ | | | | | +---------------+
>>+ PHY PHY | | | | eth0 eth1
>>+ | | | | | |
>>+ | | +- PCI-E -+ | |
>>+ | +------- MII -------+ |
>>+ +------------- MII ------------+
>>+
>>+Lets call the example switch driver for SOME switch chip "SOMEswitch". This
>>+driver takes care of PCI-E device MNGMNT. There is a netdevice instance sw0pX
>>+created for each port of a switch. These netdevices are instances
>>+of "SOMEswitch" driver. sw0pX netdevices serve as a "representation"
>>+of the switch chip. eth0 and eth1 are instances of some other existing driver.
>>+
>>+The only difference of the switch-port netdevice from the ordinary netdevice
>>+is that is implements couple more NDOs:
>>+
>>+ ndo_sw_parent_get_id - This returns the same ID for two port netdevices
>>+ of the same physical switch chip. This is
>>+ mandatory to be implemented by all switch drivers
>>+ and serves the caller for recognition of a port
>>+ netdevice.
>>+ ndo_sw_parent_* - Functions that serve for a manipulation of the switch
>>+ chip itself (it can be though of as a "parent" of the
>>+ port, therefore the name). They are not port-specific.
>>+ Caller might use arbitrary port netdevice of the same
>>+ switch and it will make no difference.
>>+ ndo_sw_port_* - Functions that serve for a port-specific manipulation.
>>diff --git a/MAINTAINERS b/MAINTAINERS
>>index 3a41fb0..776e078 100644
>>--- a/MAINTAINERS
>>+++ b/MAINTAINERS
>>@@ -9003,6 +9003,13 @@ F: lib/swiotlb.c
>> F: arch/*/kernel/pci-swiotlb.c
>> F: include/linux/swiotlb.h
>>+SWITCHDEV
>>+M: Jiri Pirko <jiri@...nulli.us>
>>+L: netdev@...r.kernel.org
>>+S: Supported
>>+F: net/switchdev/
>>+F: include/net/switchdev.h
>>+
>> SYNOPSYS ARC ARCHITECTURE
>> M: Vineet Gupta <vgupta@...opsys.com>
>> S: Supported
>>diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>>index 71922e0..97eade9 100644
>>--- a/include/linux/netdevice.h
>>+++ b/include/linux/netdevice.h
>>@@ -1017,6 +1017,12 @@ typedef u16 (*select_queue_fallback_t)(struct net_device *dev,
>> * performing GSO on a packet. The device returns true if it is
>> * able to GSO the packet, false otherwise. If the return value is
>> * false the stack will do software GSO.
>>+ *
>>+ * int (*ndo_sw_parent_id_get)(struct net_device *dev,
>>+ * struct netdev_phys_item_id *psid);
>>+ * Called to get an ID of the switch chip this port is part of.
>>+ * If driver implements this, it indicates that it represents a port
>>+ * of a switch chip.
>> */
>> struct net_device_ops {
>> int (*ndo_init)(struct net_device *dev);
>>@@ -1168,6 +1174,10 @@ struct net_device_ops {
>> int (*ndo_get_lock_subclass)(struct net_device *dev);
>> bool (*ndo_gso_check) (struct sk_buff *skb,
>> struct net_device *dev);
>>+#ifdef CONFIG_NET_SWITCHDEV
>>+ int (*ndo_sw_parent_id_get)(struct net_device *dev,
>>+ struct netdev_phys_item_id *psid);
>Can we keep the name generic and not include "sw" which implies switch here
>?.
>I understand that it is under CONFIG_NET_SWITCHDEV but we might find use for
>them in other offload scenarios in the future.
>This particular ndo can be just ndo_parent_id_get().
>And the others that do specific offloads can have "offload" in them if
>required..?.
But this is for getting parent switch id, sw should be there. If comes a
time when this might be reused to something else, we change it then.
This is internal api, easily changeable.
>
>
>
>>+#endif
>> };
>> /**
>>diff --git a/include/net/switchdev.h b/include/net/switchdev.h
>>new file mode 100644
>>index 0000000..79bf9bd
>>--- /dev/null
>>+++ b/include/net/switchdev.h
>>@@ -0,0 +1,30 @@
>>+/*
>>+ * include/net/switchdev.h - Switch device API
>>+ * Copyright (c) 2014 Jiri Pirko <jiri@...nulli.us>
>>+ *
>>+ * This program is free software; you can redistribute it and/or modify
>>+ * it under the terms of the GNU General Public License as published by
>>+ * the Free Software Foundation; either version 2 of the License, or
>>+ * (at your option) any later version.
>>+ */
>>+#ifndef _LINUX_SWITCHDEV_H_
>>+#define _LINUX_SWITCHDEV_H_
>>+
>>+#include <linux/netdevice.h>
>>+
>>+#ifdef CONFIG_NET_SWITCHDEV
>>+
>>+int netdev_sw_parent_id_get(struct net_device *dev,
>>+ struct netdev_phys_item_id *psid);
>>+
>>+#else
>>+
>>+static inline int netdev_sw_parent_id_get(struct net_device *dev,
>>+ struct netdev_phys_item_id *psid)
>>+{
>>+ return -EOPNOTSUPP;
>>+}
>>+
>>+#endif
>>+
>>+#endif /* _LINUX_SWITCHDEV_H_ */
>>diff --git a/net/Kconfig b/net/Kconfig
>>index 99815b5..ff9ffc1 100644
>>--- a/net/Kconfig
>>+++ b/net/Kconfig
>>@@ -228,6 +228,7 @@ source "net/vmw_vsock/Kconfig"
>> source "net/netlink/Kconfig"
>> source "net/mpls/Kconfig"
>> source "net/hsr/Kconfig"
>>+source "net/switchdev/Kconfig"
>> config RPS
>> boolean
>>diff --git a/net/Makefile b/net/Makefile
>>index 7ed1970..95fc694 100644
>>--- a/net/Makefile
>>+++ b/net/Makefile
>>@@ -73,3 +73,6 @@ obj-$(CONFIG_OPENVSWITCH) += openvswitch/
>> obj-$(CONFIG_VSOCKETS) += vmw_vsock/
>> obj-$(CONFIG_NET_MPLS_GSO) += mpls/
>> obj-$(CONFIG_HSR) += hsr/
>>+ifneq ($(CONFIG_NET_SWITCHDEV),)
>>+obj-y += switchdev/
>>+endif
>>diff --git a/net/switchdev/Kconfig b/net/switchdev/Kconfig
>>new file mode 100644
>>index 0000000..1557545
>>--- /dev/null
>>+++ b/net/switchdev/Kconfig
>>@@ -0,0 +1,13 @@
>>+#
>>+# Configuration for Switch device support
>>+#
>>+
>>+config NET_SWITCHDEV
>>+ boolean "Switch (and switch-ish) device support (EXPERIMENTAL)"
>>+ depends on INET
>>+ ---help---
>>+ This module provides glue between core networking code and device
>>+ drivers in order to support hardware switch chips in very generic
>>+ meaning of the word "switch". This include devices supporting L2/L3 but
>>+ also various flow offloading chips, including switches embedded into
>>+ SR-IOV NICs.
>>diff --git a/net/switchdev/Makefile b/net/switchdev/Makefile
>>new file mode 100644
>>index 0000000..5ed63ed
>>--- /dev/null
>>+++ b/net/switchdev/Makefile
>>@@ -0,0 +1,5 @@
>>+#
>>+# Makefile for the Switch device API
>>+#
>>+
>>+obj-$(CONFIG_NET_SWITCHDEV) += switchdev.o
>>diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
>>new file mode 100644
>>index 0000000..5010f646
>>--- /dev/null
>>+++ b/net/switchdev/switchdev.c
>>@@ -0,0 +1,33 @@
>>+/*
>>+ * net/switchdev/switchdev.c - Switch device API
>>+ * Copyright (c) 2014 Jiri Pirko <jiri@...nulli.us>
>>+ *
>>+ * This program is free software; you can redistribute it and/or modify
>>+ * it under the terms of the GNU General Public License as published by
>>+ * the Free Software Foundation; either version 2 of the License, or
>>+ * (at your option) any later version.
>>+ */
>>+
>>+#include <linux/kernel.h>
>>+#include <linux/types.h>
>>+#include <linux/init.h>
>>+#include <linux/netdevice.h>
>>+#include <net/switchdev.h>
>>+
>>+/**
>>+ * netdev_sw_parent_id_get - Get ID of a switch
>>+ * @dev: port device
>>+ * @psid: switch ID
>>+ *
>>+ * Get ID of a switch this port is part of.
>>+ */
>>+int netdev_sw_parent_id_get(struct net_device *dev,
>>+ struct netdev_phys_item_id *psid)
>>+{
>>+ const struct net_device_ops *ops = dev->netdev_ops;
>>+
>>+ if (!ops->ndo_sw_parent_id_get)
>>+ return -EOPNOTSUPP;
>>+ return ops->ndo_sw_parent_id_get(dev, psid);
>>+}
>>+EXPORT_SYMBOL(netdev_sw_parent_id_get);
>
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists