Change Details

Historically drivers were always traversing address lists manually. This always was a nuisance: - drivers depending on struct ifaddr, struct ifmaddr - yet another dependency on struct ifnet - dependency on how we lock address lists All three points had been changed in the past numerous times and always required at minimum recompilation of drivers, but sometimes a sweeping edit. The most recent problem came with the network epoch. Conversion from LIST to CK_LIST was performed with sed(1), but the bitter problem is that epoch isn't a lock. Thus if_addr_rlock, if_maddr_rlock were converted into epoch acqusition, but in an ugly way - the epoch tracker was placed on ifnet. Thus, parallel call into if_addr_rlock on same interface would panic. This was attempted to be corrected in r340413, which moved epoch tracker into struct thread. This also emerged FreeBSD-EN-19:11.net for the stable/12. The new KPI hides locking and internal representation of interface addresses. The inital plan was to give KPI that will call a given callback for every address. After editing all the drivers in the system, the plan was updated: - filter out only link level addresses, no driver is interested in !AF_LINK - count successfully processed addresses and return resulting count - provide basic address counting functions After converting all the drivers, the old KBIs are removed and then all epoch related hacks from struct thread removed as well. The branch is not planned to be committed as a single commit. The full commit history can be browsed here: https://github.com/glebius/FreeBSD/commits/if_foreach_maddr

Historically drivers were always traversing address lists manually. This always was a nuisance: - drivers depending on struct ifaddr, struct ifmaddr - yet another dependency on struct ifnet - dependency on how we lock address lists All three points had been changed in the past numerous times and always required at minimum recompilation of drivers, but sometimes a sweeping edit. The most recent problem came with the network epoch. Conversion from LIST to CK_LIST was performed with sed(1), but the bitter problem is that epoch isn't a lock. Thus if_addr_rlock, if_maddr_rlock were converted into epoch acqusition, but in an ugly way - the epoch tracker was placed on ifnet. Thus, parallel call into if_addr_rlock on same interface would panic. This was attempted to be corrected in r340413, which moved epoch tracker into struct thread. This also emerged FreeBSD-EN-19:11.net for the stable/12. The new KPI hides locking and internal representation of interface addresses. The inital plan was to give KPI that will call a given callback for every address. After editing all the drivers in the system, the plan was updated: - filter out only link level addresses, no driver is interested in !AF_LINK - count successfully processed addresses and return resulting count - provide basic address counting functions After converting all the drivers, the old KPIs are removed and then all epoch related hacks from struct thread removed as well. The branch is not planned to be committed as a single commit. The full commit history can be browsed here: https://github.com/glebius/FreeBSD/commits/if_foreach_maddr

Historically drivers were always traversing address lists manually. This always was a nuisance: - drivers depending on struct ifaddr, struct ifmaddr - yet another dependency on struct ifnet - dependency on how we lock address lists All three points had been changed in the past numerous times and always required at minimum recompilation of drivers, but sometimes a sweeping edit. The most recent problem came with the network epoch. Conversion from LIST to CK_LIST was performed with sed(1), but the bitter problem is that epoch isn't a lock. Thus if_addr_rlock, if_maddr_rlock were converted into epoch acqusition, but in an ugly way - the epoch tracker was placed on ifnet. Thus, parallel call into if_addr_rlock on same interface would panic. This was attempted to be corrected in r340413, which moved epoch tracker into struct thread. This also emerged FreeBSD-EN-19:11.net for the stable/12. The new KPI hides locking and internal representation of interface addresses. The inital plan was to give KPI that will call a given callback for every address. After editing all the drivers in the system, the plan was updated: - filter out only link level addresses, no driver is interested in !AF_LINK - count successfully processed addresses and return resulting count - provide basic address counting functions After converting all the drivers, the old KBIsPIs are removed and then all epoch related hacks from struct thread removed as well. The branch is not planned to be committed as a single commit. The full commit history can be browsed here: https://github.com/glebius/FreeBSD/commits/if_foreach_maddr