On 30/04/2020 20:55, Nikolay Aleksandrov wrote: > On 30/04/2020 20:50, Vladimir Oltean wrote: >> Hi Nikolay, Roopa, >> >> On Wed, 29 Apr 2020 at 19:33, Nikolay Aleksandrov >> <[email protected]> wrote: >>> >>> +CC Roopa >>> >>> On 29/04/2020 19:27, Nikolay Aleksandrov wrote: >>>> On 29/04/2020 19:19, Vladimir Oltean wrote: >>>>> From: Florian Fainelli <[email protected]> >>>>> >>>>> Commit 8db0a2ee2c63 ("net: bridge: reject DSA-enabled master netdevices >>>>> as bridge members") added a special check in br_if.c in order to check >>>>> for a DSA master network device with a tagging protocol configured. This >>>>> was done because back then, such devices, once enslaved in a bridge >>>>> would become inoperative and would not pass DSA tagged traffic anymore >>>>> due to br_handle_frame returning RX_HANDLER_CONSUMED. >>>>> >>>>> But right now we have valid use cases which do require bridging of DSA >>>>> masters. One such example is when the DSA master ports are DSA switch >>>>> ports themselves (in a disjoint tree setup). This should be completely >>>>> equivalent, functionally speaking, from having multiple DSA switches >>>>> hanging off of the ports of a switchdev driver. So we should allow the >>>>> enslaving of DSA tagged master network devices. >>>>> >>>>> Make br_handle_frame() return RX_HANDLER_PASS in order to call into the >>>>> DSA specific tagging protocol handlers, and lift the restriction from >>>>> br_add_if. >>>>> >>>>> Signed-off-by: Florian Fainelli <[email protected]> >>>>> Signed-off-by: Vladimir Oltean <[email protected]> >>>>> --- >>>>> net/bridge/br_if.c | 4 +--- >>>>> net/bridge/br_input.c | 4 +++- >>>>> 2 files changed, 4 insertions(+), 4 deletions(-) >>>>> >>>>> diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c >>>>> index ca685c0cdf95..e0fbdb855664 100644 >>>>> --- a/net/bridge/br_if.c >>>>> +++ b/net/bridge/br_if.c >>>>> @@ -18,7 +18,6 @@ >>>>> #include <linux/rtnetlink.h> >>>>> #include <linux/if_ether.h> >>>>> #include <linux/slab.h> >>>>> -#include <net/dsa.h> >>>>> #include <net/sock.h> >>>>> #include <linux/if_vlan.h> >>>>> #include <net/switchdev.h> >>>>> @@ -571,8 +570,7 @@ int br_add_if(struct net_bridge *br, struct >>>>> net_device *dev, >>>>> */ >>>>> if ((dev->flags & IFF_LOOPBACK) || >>>>> dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN || >>>>> - !is_valid_ether_addr(dev->dev_addr) || >>>>> - netdev_uses_dsa(dev)) >>>>> + !is_valid_ether_addr(dev->dev_addr)) >>>>> return -EINVAL; >>>>> >>>>> /* No bridging of bridges */ >>>>> diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c >>>>> index d5c34f36f0f4..396bc0c18cb5 100644 >>>>> --- a/net/bridge/br_input.c >>>>> +++ b/net/bridge/br_input.c >>>>> @@ -17,6 +17,7 @@ >>>>> #endif >>>>> #include <linux/neighbour.h> >>>>> #include <net/arp.h> >>>>> +#include <net/dsa.h> >>>>> #include <linux/export.h> >>>>> #include <linux/rculist.h> >>>>> #include "br_private.h" >>>>> @@ -263,7 +264,8 @@ rx_handler_result_t br_handle_frame(struct sk_buff >>>>> **pskb) >>>>> struct sk_buff *skb = *pskb; >>>>> const unsigned char *dest = eth_hdr(skb)->h_dest; >>>>> >>>>> - if (unlikely(skb->pkt_type == PACKET_LOOPBACK)) >>>>> + if (unlikely(skb->pkt_type == PACKET_LOOPBACK) || >>>>> + netdev_uses_dsa(skb->dev)) >>>>> return RX_HANDLER_PASS; >>>>> >>>>> if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) >>>>> >>>> >>>> Yet another test in fast-path for all packets. >>>> Since br_handle_frame will not be executed at all for such devices I'd >>>> suggest >>>> to look into a scheme that avoid installing rx_handler and thus prevents >>>> br_handle_frame >>>> to be called in the frist place. In case that is not possible then we can >>>> discuss adding >>>> one more test in fast-path. >>>> >>>> Actually you can just add a dummy rx_handler that simply returns >>>> RX_HANDLER_PASS for >>>> these devices and keep rx_handler_data so all br_port_get_* will continue >>>> working. >>>> >>>> Thanks, >>>> Nik >>>> >> >> Actually both of those are problematic, since br_port_get_check_rcu >> and br_port_get_check_rtnl check for the rx_handler pointer against >> br_handle_frame. > > Right, but they can be changed to use a different validation. >
To be more specific I was referring to the most frequently used br_port_get_rcu/rtnl helpers. The versions with _check can be changed to use a different validation. >> Actually a plain old revert of 8db0a2ee2c63 works just fine for what I >> need it to, not sure if there's any point in making this any more >> complicated than that. >> What do you think? >> > > Sounds much better to me if it works for you. > > Thanks! > >> Thanks, >> -Vladimir >> >
