if_awg: avoid hole in the rx ring buffer when mbuf allocation fails
Use a spare dma map when attempting to map a new mbuf on the rx path. If the mbuf allocation fails or the dma map loading for the new mbuf fails just reuse the old mbuf and increase the drop counter. Submitted by: Guy Yur <guyyur@gmail.com> Differential Revision: https://reviews.freebsd.org/D12538
This commit is contained in:
Emmanuel Vadot
parent
337c6940a9
commit
bd9063297c
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=325984
@ -179,6 +179,7 @@ struct awg_rxring {
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bus_addr_t desc_ring_paddr;
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bus_dma_tag_t buf_tag;
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struct awg_bufmap buf_map[RX_DESC_COUNT];
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bus_dmamap_t buf_spare_map;
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u_int cur;
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};
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@ -519,24 +520,45 @@ awg_setup_rxdesc(struct awg_softc *sc, int index, bus_addr_t paddr)
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sc->rx.desc_ring[index].addr = htole32((uint32_t)paddr);
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sc->rx.desc_ring[index].size = htole32(size);
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sc->rx.desc_ring[index].next =
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htole32(sc->rx.desc_ring_paddr + DESC_OFF(RX_NEXT(index)));
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sc->rx.desc_ring[index].status = htole32(status);
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}
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static int
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awg_setup_rxbuf(struct awg_softc *sc, int index, struct mbuf *m)
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static void
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awg_reuse_rxdesc(struct awg_softc *sc, int index)
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{
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bus_dma_segment_t seg;
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int error, nsegs;
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sc->rx.desc_ring[index].status = htole32(RX_DESC_CTL);
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}
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static int
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awg_newbuf_rx(struct awg_softc *sc, int index)
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{
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struct mbuf *m;
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bus_dma_segment_t seg;
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bus_dmamap_t map;
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int nsegs;
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m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
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if (m == NULL)
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return (ENOBUFS);
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m->m_pkthdr.len = m->m_len = m->m_ext.ext_size;
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m_adj(m, ETHER_ALIGN);
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error = bus_dmamap_load_mbuf_sg(sc->rx.buf_tag,
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sc->rx.buf_map[index].map, m, &seg, &nsegs, 0);
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if (error != 0)
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return (error);
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if (bus_dmamap_load_mbuf_sg(sc->rx.buf_tag, sc->rx.buf_spare_map,
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m, &seg, &nsegs, BUS_DMA_NOWAIT) != 0) {
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m_freem(m);
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return (ENOBUFS);
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}
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if (sc->rx.buf_map[index].mbuf != NULL) {
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bus_dmamap_sync(sc->rx.buf_tag, sc->rx.buf_map[index].map,
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BUS_DMASYNC_POSTREAD);
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bus_dmamap_unload(sc->rx.buf_tag, sc->rx.buf_map[index].map);
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}
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map = sc->rx.buf_map[index].map;
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sc->rx.buf_map[index].map = sc->rx.buf_spare_map;
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sc->rx.buf_spare_map = map;
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bus_dmamap_sync(sc->rx.buf_tag, sc->rx.buf_map[index].map,
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BUS_DMASYNC_PREREAD);
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@ -546,18 +568,6 @@ awg_setup_rxbuf(struct awg_softc *sc, int index, struct mbuf *m)
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return (0);
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}
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static struct mbuf *
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awg_alloc_mbufcl(struct awg_softc *sc)
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{
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struct mbuf *m;
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m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
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if (m != NULL)
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m->m_pkthdr.len = m->m_len = m->m_ext.ext_size;
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return (m);
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}
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static void
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awg_start_locked(struct awg_softc *sc)
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{
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@ -840,7 +850,7 @@ static int
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awg_rxintr(struct awg_softc *sc)
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{
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if_t ifp;
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struct mbuf *m, *m0, *mh, *mt;
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struct mbuf *m, *mh, *mt;
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int error, index, len, cnt, npkt;
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uint32_t status;
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@ -857,61 +867,62 @@ awg_rxintr(struct awg_softc *sc)
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if ((status & RX_DESC_CTL) != 0)
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break;
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bus_dmamap_sync(sc->rx.buf_tag, sc->rx.buf_map[index].map,
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BUS_DMASYNC_POSTREAD);
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bus_dmamap_unload(sc->rx.buf_tag, sc->rx.buf_map[index].map);
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len = (status & RX_FRM_LEN) >> RX_FRM_LEN_SHIFT;
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if (len != 0) {
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m = sc->rx.buf_map[index].mbuf;
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m->m_pkthdr.rcvif = ifp;
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m->m_pkthdr.len = len;
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m->m_len = len;
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if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
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if ((if_getcapenable(ifp) & IFCAP_RXCSUM) != 0 &&
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(status & RX_FRM_TYPE) != 0) {
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m->m_pkthdr.csum_flags = CSUM_IP_CHECKED;
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if ((status & RX_HEADER_ERR) == 0)
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m->m_pkthdr.csum_flags |= CSUM_IP_VALID;
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if ((status & RX_PAYLOAD_ERR) == 0) {
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m->m_pkthdr.csum_flags |=
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CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
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m->m_pkthdr.csum_data = 0xffff;
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}
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}
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m->m_nextpkt = NULL;
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if (mh == NULL)
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mh = m;
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else
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mt->m_nextpkt = m;
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mt = m;
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++cnt;
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++npkt;
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if (cnt == awg_rx_batch) {
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AWG_UNLOCK(sc);
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if_input(ifp, mh);
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AWG_LOCK(sc);
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mh = mt = NULL;
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cnt = 0;
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}
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if (len == 0) {
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if ((status & (RX_NO_ENOUGH_BUF_ERR | RX_OVERFLOW_ERR)) != 0)
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if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
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awg_reuse_rxdesc(sc, index);
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continue;
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}
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if ((m0 = awg_alloc_mbufcl(sc)) != NULL) {
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error = awg_setup_rxbuf(sc, index, m0);
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if (error != 0) {
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/* XXX hole in RX ring */
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}
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} else
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m = sc->rx.buf_map[index].mbuf;
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error = awg_newbuf_rx(sc, index);
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if (error != 0) {
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if_inc_counter(ifp, IFCOUNTER_IQDROPS, 1);
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awg_reuse_rxdesc(sc, index);
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continue;
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}
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m->m_pkthdr.rcvif = ifp;
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m->m_pkthdr.len = len;
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m->m_len = len;
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if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
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if ((if_getcapenable(ifp) & IFCAP_RXCSUM) != 0 &&
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(status & RX_FRM_TYPE) != 0) {
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m->m_pkthdr.csum_flags = CSUM_IP_CHECKED;
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if ((status & RX_HEADER_ERR) == 0)
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m->m_pkthdr.csum_flags |= CSUM_IP_VALID;
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if ((status & RX_PAYLOAD_ERR) == 0) {
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m->m_pkthdr.csum_flags |=
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CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
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m->m_pkthdr.csum_data = 0xffff;
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}
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}
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m->m_nextpkt = NULL;
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if (mh == NULL)
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mh = m;
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else
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mt->m_nextpkt = m;
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mt = m;
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++cnt;
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++npkt;
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if (cnt == awg_rx_batch) {
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AWG_UNLOCK(sc);
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if_input(ifp, mh);
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AWG_LOCK(sc);
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mh = mt = NULL;
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cnt = 0;
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}
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}
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if (index != sc->rx.cur) {
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bus_dmamap_sync(sc->rx.desc_tag, sc->rx.desc_map,
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BUS_DMASYNC_PREWRITE);
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BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
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}
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if (mh != NULL) {
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@ -1500,7 +1511,6 @@ static int
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awg_setup_dma(device_t dev)
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{
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struct awg_softc *sc;
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struct mbuf *m;
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int error, i;
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sc = device_get_softc(dev);
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@ -1615,18 +1625,25 @@ awg_setup_dma(device_t dev)
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return (error);
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}
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error = bus_dmamap_create(sc->rx.buf_tag, 0, &sc->rx.buf_spare_map);
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if (error != 0) {
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device_printf(dev,
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"cannot create RX buffer spare map\n");
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return (error);
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}
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for (i = 0; i < RX_DESC_COUNT; i++) {
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sc->rx.desc_ring[i].next =
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htole32(sc->rx.desc_ring_paddr + DESC_OFF(RX_NEXT(i)));
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error = bus_dmamap_create(sc->rx.buf_tag, 0,
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&sc->rx.buf_map[i].map);
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if (error != 0) {
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device_printf(dev, "cannot create RX buffer map\n");
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return (error);
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}
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if ((m = awg_alloc_mbufcl(sc)) == NULL) {
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device_printf(dev, "cannot allocate RX mbuf\n");
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return (ENOMEM);
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}
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error = awg_setup_rxbuf(sc, i, m);
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sc->rx.buf_map[i].mbuf = NULL;
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error = awg_newbuf_rx(sc, i);
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if (error != 0) {
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device_printf(dev, "cannot create RX buffer\n");
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return (error);
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