Date: Mon, 16 Feb 2026 10:01:05 +0000 From: Zhenlei Huang <zlei@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: fe1299f16c55 - stable/15 - lagg: Avoid dropping locks when starting the interface Message-ID: <6992eae1.24129.509b476e@gitrepo.freebsd.org>
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The branch stable/15 has been updated by zlei: URL: https://cgit.FreeBSD.org/src/commit/?id=fe1299f16c55f09fa053e71bf1e1feee7f32527f commit fe1299f16c55f09fa053e71bf1e1feee7f32527f Author: Zhenlei Huang <zlei@FreeBSD.org> AuthorDate: 2026-02-11 18:15:41 +0000 Commit: Zhenlei Huang <zlei@FreeBSD.org> CommitDate: 2026-02-16 10:00:30 +0000 lagg: Avoid dropping locks when starting the interface The init routine of a lagg(4) interface will not change during the whole lifecycle. So we can call lagg_init() directly instead of through the function pointer. Well, that requires a drop and pickup lock, which unnecessarily expose a small race window. Refactor lagg_init() into lagg_init_locked() and call the later one to avoid that. Meanwhile, delay updating the driver managed status until after the interface is really ready. Reviewed by: markj MFC after: 5 days Differential Revision: https://reviews.freebsd.org/D55198 (cherry picked from commit c182cf646a4f995fa8506afd8afc9541c4d32905) --- sys/net/if_lagg.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) diff --git a/sys/net/if_lagg.c b/sys/net/if_lagg.c index c30af5bfcc4e..23ad4f72d255 100644 --- a/sys/net/if_lagg.c +++ b/sys/net/if_lagg.c @@ -139,6 +139,7 @@ static int lagg_port_checkstacking(struct lagg_softc *); static void lagg_port2req(struct lagg_port *, struct lagg_reqport *); static void lagg_if_updown(struct lagg_softc *, bool); static void lagg_init(void *); +static void lagg_init_locked(struct lagg_softc *); static void lagg_stop(struct lagg_softc *); static int lagg_ioctl(struct ifnet *, u_long, caddr_t); #if defined(KERN_TLS) || defined(RATELIMIT) @@ -1282,16 +1283,21 @@ static void lagg_init(void *xsc) { struct lagg_softc *sc = (struct lagg_softc *)xsc; + + LAGG_XLOCK(sc); + lagg_init_locked(sc); + LAGG_XUNLOCK(sc); +} + +static void +lagg_init_locked(struct lagg_softc *sc) +{ struct ifnet *ifp = sc->sc_ifp; struct lagg_port *lp; - LAGG_XLOCK(sc); - if (ifp->if_drv_flags & IFF_DRV_RUNNING) { - LAGG_XUNLOCK(sc); + LAGG_XLOCK_ASSERT(sc); + if ((ifp->if_drv_flags & IFF_DRV_RUNNING) != 0) return; - } - - ifp->if_drv_flags |= IFF_DRV_RUNNING; /* * Update the port lladdrs if needed. @@ -1313,8 +1319,7 @@ lagg_init(void *xsc) lagg_watchdog_infiniband(sc); mtx_unlock(&sc->sc_mtx); } - - LAGG_XUNLOCK(sc); + ifp->if_drv_flags |= IFF_DRV_RUNNING; } static void @@ -1677,24 +1682,21 @@ lagg_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) lagg_setflags(lp, 1); } - if (!(ifp->if_flags & IFF_UP) && - (ifp->if_drv_flags & IFF_DRV_RUNNING)) { + if ((ifp->if_flags & IFF_UP) == 0 && + (ifp->if_drv_flags & IFF_DRV_RUNNING) != 0) /* * If interface is marked down and it is running, * then stop and disable it. */ lagg_stop(sc); - LAGG_XUNLOCK(sc); - } else if ((ifp->if_flags & IFF_UP) && - !(ifp->if_drv_flags & IFF_DRV_RUNNING)) { + else if ((ifp->if_flags & IFF_UP) != 0 && + (ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) /* * If interface is marked up and it is stopped, then * start it. */ - LAGG_XUNLOCK(sc); - (*ifp->if_init)(sc); - } else - LAGG_XUNLOCK(sc); + lagg_init_locked(sc); + LAGG_XUNLOCK(sc); break; case SIOCADDMULTI: case SIOCDELMULTI:home | help
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