git: c3bd32f225ec - stable/13 - epair: Avoid loading m_flags into a short
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Date: Mon, 13 Mar 2023 15:53:29 UTC
The branch stable/13 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=c3bd32f225ec093ba0f7cd7fc1a000b02aad5211 commit c3bd32f225ec093ba0f7cd7fc1a000b02aad5211 Author: Mark Johnston <markj@FreeBSD.org> AuthorDate: 2023-03-06 14:39:17 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2023-03-13 15:53:16 +0000 epair: Avoid loading m_flags into a short The m_flags field of struct mbuf is 24 bits wide and so gets truncated in a couple of places in the epair code. Instead of preserving the entire flag set, just remember whether M_BCAST or M_MCAST is set. MFC after: 1 week Sponsored by: Klara, Inc. (cherry picked from commit 48227d1c6db8fceaceebbf8578612302d64ca170) --- sys/net/if_epair.c | 95 +++++++++++++++++++++++++++++++----------------------- 1 file changed, 54 insertions(+), 41 deletions(-) diff --git a/sys/net/if_epair.c b/sys/net/if_epair.c index e7257f5fa551..05667633fa42 100644 --- a/sys/net/if_epair.c +++ b/sys/net/if_epair.c @@ -188,39 +188,14 @@ epair_tx_start_deferred(void *arg, int pending) if_rele(sc->ifp); } -static int -epair_menq(struct mbuf *m, struct epair_softc *osc) +static struct epair_queue * +epair_select_queue(struct epair_softc *sc, struct mbuf *m) { - struct ifnet *ifp, *oifp; - int len, ret; - int ridx; - short mflags; - struct epair_queue *q = NULL; uint32_t bucket; #ifdef RSS struct ether_header *eh; -#endif - - /* - * I know this looks weird. We pass the "other sc" as we need that one - * and can get both ifps from it as well. - */ - oifp = osc->ifp; - ifp = osc->oifp; - - M_ASSERTPKTHDR(m); - epair_clear_mbuf(m); - if_setrcvif(m, oifp); - M_SETFIB(m, oifp->if_fib); - - /* Save values as once the mbuf is queued, it's not ours anymore. */ - len = m->m_pkthdr.len; - mflags = m->m_flags; - - MPASS(m->m_nextpkt == NULL); - MPASS((m->m_pkthdr.csum_flags & CSUM_SND_TAG) == 0); + int ret; -#ifdef RSS ret = rss_m2bucket(m, &bucket); if (ret) { /* Actually hash the packet. */ @@ -246,7 +221,43 @@ epair_menq(struct mbuf *m, struct epair_softc *osc) #else bucket = 0; #endif - q = &osc->queues[bucket]; + return (&sc->queues[bucket]); +} + +static void +epair_prepare_mbuf(struct mbuf *m, struct ifnet *src_ifp) +{ + M_ASSERTPKTHDR(m); + epair_clear_mbuf(m); + if_setrcvif(m, src_ifp); + M_SETFIB(m, src_ifp->if_fib); + + MPASS(m->m_nextpkt == NULL); + MPASS((m->m_pkthdr.csum_flags & CSUM_SND_TAG) == 0); +} + +static void +epair_menq(struct mbuf *m, struct epair_softc *osc) +{ + struct ifnet *ifp, *oifp; + int len, ret; + int ridx; + bool mcast; + + /* + * I know this looks weird. We pass the "other sc" as we need that one + * and can get both ifps from it as well. + */ + oifp = osc->ifp; + ifp = osc->oifp; + + epair_prepare_mbuf(m, oifp); + + /* Save values as once the mbuf is queued, it's not ours anymore. */ + len = m->m_pkthdr.len; + mcast = (m->m_flags & (M_BCAST | M_MCAST)) != 0; + + struct epair_queue *q = epair_select_queue(osc, m); atomic_set_long(&q->state, (1 << BIT_MBUF_QUEUED)); ridx = atomic_load_int(&q->ridx); @@ -255,7 +266,7 @@ epair_menq(struct mbuf *m, struct epair_softc *osc) /* Ring is full. */ if_inc_counter(ifp, IFCOUNTER_OQDROPS, 1); m_freem(m); - return (0); + return; } if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1); @@ -265,15 +276,13 @@ epair_menq(struct mbuf *m, struct epair_softc *osc) * the logic another time. */ if_inc_counter(ifp, IFCOUNTER_OBYTES, len); - if (mflags & (M_BCAST|M_MCAST)) + if (mcast) if_inc_counter(ifp, IFCOUNTER_OMCASTS, 1); /* Someone else received the packet. */ if_inc_counter(oifp, IFCOUNTER_IPACKETS, 1); if (!atomic_testandset_long(&q->state, BIT_QUEUE_TASK)) - taskqueue_enqueue(epair_tasks.tq[bucket], &q->tx_task); - - return (0); + taskqueue_enqueue(epair_tasks.tq[q->id], &q->tx_task); } static void @@ -317,8 +326,10 @@ epair_transmit(struct ifnet *ifp, struct mbuf *m) { struct epair_softc *sc; struct ifnet *oifp; - int error, len; - short mflags; +#ifdef ALTQ + int len; + bool mcast; +#endif if (m == NULL) return (0); @@ -355,10 +366,12 @@ epair_transmit(struct ifnet *ifp, struct mbuf *m) m_freem(m); return (0); } - len = m->m_pkthdr.len; - mflags = m->m_flags; #ifdef ALTQ + len = m->m_pkthdr.len; + mcast = (m->m_flags & (M_BCAST | M_MCAST)) != 0; + int error = 0; + /* Support ALTQ via the classic if_start() path. */ IF_LOCK(&ifp->if_snd); if (ALTQ_IS_ENABLED(&ifp->if_snd)) { @@ -368,7 +381,7 @@ epair_transmit(struct ifnet *ifp, struct mbuf *m) IF_UNLOCK(&ifp->if_snd); if (!error) { if_inc_counter(ifp, IFCOUNTER_OBYTES, len); - if (mflags & (M_BCAST|M_MCAST)) + if (mcast) if_inc_counter(ifp, IFCOUNTER_OMCASTS, 1); epair_start(ifp); } @@ -377,8 +390,8 @@ epair_transmit(struct ifnet *ifp, struct mbuf *m) IF_UNLOCK(&ifp->if_snd); #endif - error = epair_menq(m, oifp->if_softc); - return (error); + epair_menq(m, oifp->if_softc); + return (0); } static int