Nikolay Aleksandrov
2022-Jun-02 09:33 UTC
[Bridge] [PATCH V3 net-next 1/4] net: bridge: add fdb flag to extent locked port feature
On 02/06/2022 12:17, Hans Schultz wrote:> On tis, maj 31, 2022 at 17:23, Ido Schimmel <idosch at nvidia.com> wrote: >> On Tue, May 31, 2022 at 11:34:21AM +0200, Hans Schultz wrote: >>>> Just to give you another data point about how this works in other >>>> devices, I can say that at least in Spectrum this works a bit >>>> differently. Packets that ingress via a locked port and incur an FDB >>>> miss are trapped to the CPU where they should be injected into the Rx >>>> path so that the bridge will create the 'locked' FDB entry and notify it >>>> to user space. The packets are obviously rated limited as the CPU cannot >>>> handle billions of packets per second, unlike the ASIC. The limit is not >>>> per bridge port (or even per bridge), but instead global to the entire >>>> device. >>> >>> Btw, will the bridge not create a SWITCHDEV_FDB_ADD_TO_DEVICE event >>> towards the switchcore in the scheme you mention and thus add an entry >>> that opens up for the specified mac address? >> >> It will, but the driver needs to ignore FDB entries that are notified >> with locked flag. I see that you extended 'struct >> switchdev_notifier_fdb_info' with the locked flag, but it's not >> initialized in br_switchdev_fdb_populate(). Can you add it in the next >> version? > > An issue with sending the flag to the driver is that port_fdb_add() is > suddenly getting more and more arguments and getting messy in my > opinion, but maybe that's just how it is... > > Another issue is that > bridge fdb add MAC dev DEV master static > seems to add the entry with the SELF flag set, which I don't think is > what we would want it to do or?I don't see such thing (hacked iproute2 to print the flags before cmd): $ bridge fdb add 00:11:22:33:44:55 dev vnet110 master static flags 0x4 0x4 = NTF_MASTER only> Also the replace command is not really supported properly as it is. I > have made a fix for that which looks something like this: > > diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c > index 6cbb27e3b976..f43aa204f375 100644 > --- a/net/bridge/br_fdb.c > +++ b/net/bridge/br_fdb.c > @@ -917,6 +917,9 @@ static int fdb_add_entry(struct net_bridge *br, struct net_bridge_port *source, > if (flags & NLM_F_EXCL) > return -EEXIST; > > + if (flags & NLM_F_REPLACE) > + modified = true; > + > if (READ_ONCE(fdb->dst) != source) { > WRITE_ONCE(fdb->dst, source); > modified = true; > > The argument for always sending notifications to the driver in the case > of replace is that a replace command will refresh the entries timeout if > the entry is the same. Any thoughts on this?I don't think so. It always updates its "used" timer, not its "updated" timer which is the one for expire. A replace that doesn't actually change anything on the entry shouldn't generate a notification.
Hans Schultz
2022-Jun-02 10:17 UTC
[Bridge] [PATCH V3 net-next 1/4] net: bridge: add fdb flag to extent locked port feature
On tor, jun 02, 2022 at 12:33, Nikolay Aleksandrov <razor at blackwall.org> wrote:> On 02/06/2022 12:17, Hans Schultz wrote: >> On tis, maj 31, 2022 at 17:23, Ido Schimmel <idosch at nvidia.com> wrote: >>> On Tue, May 31, 2022 at 11:34:21AM +0200, Hans Schultz wrote:>> Another issue is that >> bridge fdb add MAC dev DEV master static >> seems to add the entry with the SELF flag set, which I don't think is >> what we would want it to do or? > > I don't see such thing (hacked iproute2 to print the flags before cmd): > $ bridge fdb add 00:11:22:33:44:55 dev vnet110 master static > flags 0x4 > > 0x4 = NTF_MASTER only >I also get 0x4 from iproute2, but I still get SELF entries when I look with: bridge fdb show dev DEV>> Also the replace command is not really supported properly as it is. I >> have made a fix for that which looks something like this: >> >> diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c >> index 6cbb27e3b976..f43aa204f375 100644 >> --- a/net/bridge/br_fdb.c >> +++ b/net/bridge/br_fdb.c >> @@ -917,6 +917,9 @@ static int fdb_add_entry(struct net_bridge *br, struct net_bridge_port *source, >> if (flags & NLM_F_EXCL) >> return -EEXIST; >> >> + if (flags & NLM_F_REPLACE) >> + modified = true; >> + >> if (READ_ONCE(fdb->dst) != source) { >> WRITE_ONCE(fdb->dst, source); >> modified = true; >> >> The argument for always sending notifications to the driver in the case >> of replace is that a replace command will refresh the entries timeout if >> the entry is the same. Any thoughts on this? > > I don't think so. It always updates its "used" timer, not its "updated" timer which is the one > for expire. A replace that doesn't actually change anything on the entry shouldn't generate > a notification.Okay, so then there is missing checks on flags as the issue arose from replacing locked entries with dynamic entries. I will do another fix based on flags as modified needs to be true for the driver to get notified.