Re: [RFC PATCH net-next 3/4] rocker: add fwd_mark support

Jiri Pirko
2015-06-15T05:49:14Z

Sun, Jun 14, 2015 at 08:00:11PM CEST, sfeldma@gmail.com wrote:
>On Sun, Jun 14, 2015 at 12:02 AM, Jiri Pirko <jiri@resnulli.us> wrote:
>> Sat, Jun 13, 2015 at 08:04:29PM CEST, sfeldma@gmail.com wrote:
>>>From: Scott Feldman <sfeldma@gmail.com>
>>>
>>>If device flags ingress packet as "fwd offload", mark the skb->fwd_mark
>>>using the ingress port's dev->fwd_mark. This will be the hint to the
>>>kernel that this packet has already been forwarded by device to egress
>>>ports matching skb->fwd_mark.
>>>
>>>For rocker, derive port dev->fwd_mark based on device switch ID. If port
>>>is bridged, include the bridge's ifindex in the key for deriving
>>>dev->fwd_mark.
>>>
>>>Signed-off-by: Scott Feldman <sfeldma@gmail.com>
>>>---
>>> drivers/net/ethernet/rocker/rocker.c | 24 ++++++++++++++++++++++++
>>> drivers/net/ethernet/rocker/rocker.h | 1 +
>>> 2 files changed, 25 insertions(+)
>>>
>>>diff --git a/drivers/net/ethernet/rocker/rocker.c b/drivers/net/ethernet/rocker/rocker.c
>>>index a06b93d..81407d8 100644
>>>--- a/drivers/net/ethernet/rocker/rocker.c
>>>+++ b/drivers/net/ethernet/rocker/rocker.c
>>>@@ -4701,6 +4701,7 @@ static int rocker_port_rx_proc(const struct rocker *rocker,
>>> const struct rocker_tlv *attrs[ROCKER_TLV_RX_MAX + 1];
>>> struct sk_buff *skb = rocker_desc_cookie_ptr_get(desc_info);
>>> size_t rx_len;
>>>+ u16 rx_flags = 0;
>>>
>>> if (!skb)
>>> return -ENOENT;
>>>@@ -4708,6 +4709,8 @@ static int rocker_port_rx_proc(const struct rocker *rocker,
>>> rocker_tlv_parse_desc(attrs, ROCKER_TLV_RX_MAX, desc_info);
>>> if (!attrs[ROCKER_TLV_RX_FRAG_LEN])
>>> return -EINVAL;
>>>+ if (attrs[ROCKER_TLV_RX_FLAGS])
>>>+ rx_flags = rocker_tlv_get_u16(attrs[ROCKER_TLV_RX_FLAGS]);
>>>
>>> rocker_dma_rx_ring_skb_unmap(rocker, attrs);
>>>
>>>@@ -4715,6 +4718,9 @@ static int rocker_port_rx_proc(const struct rocker *rocker,
>>> skb_put(skb, rx_len);
>>> skb->protocol = eth_type_trans(skb, rocker_port->dev);
>>>
>>>+ if (rx_flags & ROCKER_RX_FLAGS_FWD_OFFLOAD)
>>
>> Nasty :) I'm not sure that this can be easily done for real hw. But
>> anyway, that is a driver problem.
>
>Why is this nasty?
>
>Some real HW can do it, some can't. Some that can go into detail of
>the nature of the fwd. Rocker can do it because we know when we copy
>a pkt to the CPU port that's also been forwarded.

Yep, rocker has advantage in this.

>
>>
>>>+ skb->fwd_mark = rocker_port->dev->fwd_mark;
>>>+
>>> rocker_port->dev->stats.rx_packets++;
>>> rocker_port->dev->stats.rx_bytes += skb->len;
>>>
>>>@@ -4814,6 +4820,21 @@ static void rocker_port_dev_addr_init(struct rocker_port *rocker_port)
>>> }
>>> }
>>>
>>>+static void rocker_port_fwd_mark_set(struct rocker_port *rocker_port)
>>>+{
>>>+ struct rocker *rocker = rocker_port->rocker;
>>>+ struct {
>>>+ u64 hw_id;
>>>+ int ifindex;
>>>+ } key = {
>>>+ .hw_id = rocker->hw.id,
>>>+ .ifindex = rocker_port_is_bridged(rocker_port) ?
>>>+ rocker_port->bridge_dev->ifindex : 0,
>>>+ };
>>>+
>>>+ rocker_port->dev->fwd_mark = switchdev_mark_get(&key, sizeof(key));
>>>+}
>>>+
>>> static int rocker_probe_port(struct rocker *rocker, unsigned int port_number)
>>> {
>>> const struct pci_dev *pdev = rocker->pdev;
>>>@@ -4832,6 +4853,7 @@ static int rocker_probe_port(struct rocker *rocker, unsigned int port_number)
>>> rocker_port->pport = port_number + 1;
>>> rocker_port->brport_flags = BR_LEARNING | BR_LEARNING_SYNC;
>>> INIT_LIST_HEAD(&rocker_port->trans_mem);
>>>+ rocker_port_fwd_mark_set(rocker_port);
>>>
>>> rocker_port_dev_addr_init(rocker_port);
>>> dev->netdev_ops = &rocker_port_netdev_ops;
>>>@@ -5131,6 +5153,7 @@ static int rocker_port_bridge_join(struct rocker_port *rocker_port,
>>> rocker_port_internal_vlan_id_get(rocker_port, bridge->ifindex);
>>>
>>> rocker_port->bridge_dev = bridge;
>>>+ rocker_port_fwd_mark_set(rocker_port);
>>>
>>> return rocker_port_vlan_add(rocker_port, SWITCHDEV_TRANS_NONE,
>>> untagged_vid, 0);
>>>@@ -5152,6 +5175,7 @@ static int rocker_port_bridge_leave(struct rocker_port *rocker_port)
>>> rocker_port->dev->ifindex);
>>>
>>> rocker_port->bridge_dev = NULL;
>>>+ rocker_port_fwd_mark_set(rocker_port);
>>
>>
>> Hmm, wouldn't it make sense to move fwd_mark setting from drivers to
>> switchdev core? This will look the same for all drivers, so I think it
>> should be in common swithdev core, always generated according to "switch id".
>
>This is setting the fwd_mark on the port during init, not the skb
>during run-time.

I know this particular code is called during initialization.

But what do you say about my idea to move common code sreating fwd_mark and
actual skb marking into swtichdev code?

>
>> So all what driver needs to do is to call some helper like:
>> static inline void switchdev_skb_fwd_mark(struct sk_buff *skb,
>> struct net_device *dev) {
>> skb->fwd_mark = dev->fwd_mark;
>> }
>>
>>