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lagg: Avoid dropping locks when starting the interface

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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
This commit is contained in:
Zhenlei Huang
2026-02-12 02:15:41 +08:00
parent 71569594d8
commit c182cf646a
1 changed files with 19 additions and 17 deletions
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sys/net/if_lagg.c
+19 -17
View File
@@ -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)
@@ -1279,16 +1280,21 @@ 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.
@@ -1310,8 +1316,7 @@ 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
@@ -1674,24 +1679,21 @@ 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: