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

Jiri Pirko
2015-06-14T07:02:59Z

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.

>+ 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".

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;
}