diff options
author | sam <sam@FreeBSD.org> | 2005-03-29 20:54:31 +0000 |
---|---|---|
committer | sam <sam@FreeBSD.org> | 2005-03-29 20:54:31 +0000 |
commit | a946e6decee6b0cf3f5a22e76ea9b03df221be20 (patch) | |
tree | 211e678e7ecc26e7afa66e28e7ba9fcb64d43ff1 /sys/dev | |
parent | 44f7579d90b5186e751df41c12f37d8b467d7e7b (diff) | |
download | FreeBSD-src-a946e6decee6b0cf3f5a22e76ea9b03df221be20.zip FreeBSD-src-a946e6decee6b0cf3f5a22e76ea9b03df221be20.tar.gz |
replace m_defrag with something more suitable
Diffstat (limited to 'sys/dev')
-rw-r--r-- | sys/dev/ath/if_ath.c | 91 |
1 files changed, 88 insertions, 3 deletions
diff --git a/sys/dev/ath/if_ath.c b/sys/dev/ath/if_ath.c index df046d3..e0d7584 100644 --- a/sys/dev/ath/if_ath.c +++ b/sys/dev/ath/if_ath.c @@ -2894,6 +2894,89 @@ ath_tx_cleanup(struct ath_softc *sc) ath_tx_cleanupq(sc, &sc->sc_txq[i]); } +/* + * Defragment an mbuf chain, returning at most maxfrags separate + * mbufs+clusters. If this is not possible NULL is returned and + * the original mbuf chain is reclaimed. We use two techniques: + * collapsing consecutive mbufs and replacing consecutive mbufs + * by a cluster. + */ +static struct mbuf * +ath_defrag(struct mbuf *m0, int how, int maxfrags) +{ + struct mbuf *m, *n, *n2, **prev; + u_int curfrags; + + /* + * Calculate the current number of frags. + */ + curfrags = 0; + for (m = m0; m != NULL; m = m->m_next) + curfrags++; + /* + * First, try to collapse mbufs. Note that we always collapse + * towards the front so we don't need to deal with moving the + * pkthdr. This may be suboptimal if the first mbuf has much + * less data than the following. + */ + m = m0; +again: + for (;;) { + n = m->m_next; + if (n == NULL) + break; + if (n->m_len < M_TRAILINGSPACE(m)) { + bcopy(mtod(n, void *), mtod(m, char *) + m->m_len, + n->m_len); + m->m_len += n->m_len; + m->m_next = n->m_next; + m_free(n); + if (--curfrags <= maxfrags) + return m0; + } else + m = n; + } + KASSERT(maxfrags > 1, + ("maxfrags %u, but normal collapse failed", maxfrags)); + /* + * Collapse consecutive mbufs to a cluster. + */ + prev = &m0->m_next; /* NB: not the first mbuf */ + while ((n = *prev) != NULL) { + if ((n2 = n->m_next) != NULL && + n->m_len + n2->m_len < MCLBYTES) { + m = m_getcl(how, MT_DATA, 0); + if (m == NULL) + goto bad; + bcopy(mtod(n, void *), mtod(m, void *), n->m_len); + bcopy(mtod(n2, void *), mtod(m, char *) + n->m_len, + n2->m_len); + m->m_len = n->m_len + n2->m_len; + m->m_next = n2->m_next; + *prev = m; + m_free(n); + m_free(n2); + if (--curfrags <= maxfrags) /* +1 cl -2 mbufs */ + return m0; + /* + * Still not there, try the normal collapse + * again before we allocate another cluster. + */ + goto again; + } + prev = &n->m_next; + } + /* + * No place where we can collapse to a cluster; punt. + * This can occur if, for example, you request 2 frags + * but the packet requires that both be clusters (we + * never reallocate the first mbuf to avoid moving the + * packet header). + */ +bad: + return NULL; +} + static int ath_tx_start(struct ath_softc *sc, struct ieee80211_node *ni, struct ath_buf *bf, struct mbuf *m0) @@ -2912,6 +2995,7 @@ ath_tx_start(struct ath_softc *sc, struct ieee80211_node *ni, struct ath_buf *bf const HAL_RATE_TABLE *rt; HAL_BOOL shortPreamble; struct ath_node *an; + struct mbuf *m; wh = mtod(m0, struct ieee80211_frame *); iswep = wh->i_fc[1] & IEEE80211_FC1_WEP; @@ -2987,12 +3071,13 @@ ath_tx_start(struct ath_softc *sc, struct ieee80211_node *ni, struct ath_buf *bf */ if (bf->bf_nseg > ATH_TXDESC) { /* too many desc's, linearize */ sc->sc_stats.ast_tx_linear++; - m0 = m_defrag(m0, M_DONTWAIT); - if (m0 == NULL) { - sc->sc_stats.ast_tx_nombuf++; + m = ath_defrag(m0, M_DONTWAIT, ATH_TXDESC); + if (m == NULL) { m_freem(m0); + sc->sc_stats.ast_tx_nombuf++; return ENOMEM; } + m0 = m; error = bus_dmamap_load_mbuf_sg(sc->sc_dmat, bf->bf_dmamap, m0, bf->bf_segs, &bf->bf_nseg, BUS_DMA_NOWAIT); |