handle fragmented mbuf DMA segments in the qwx(4) Tx path

Fixes qwx0: failed to map Tx buffer: 27

diff --git a/sys/dev/ic/qwx.c b/sys/dev/ic/qwx.c
index 9e90867..b20a2fd 100644 (file)
--- a/sys/dev/ic/qwx.c
+++ b/sys/dev/ic/qwx.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: qwx.c,v 1.19 2024/02/08 11:06:50 stsp Exp $   */
+/*     $OpenBSD: qwx.c,v 1.20 2024/02/08 11:09:53 stsp Exp $   */
 
 /*
  * Copyright 2023 Stefan Sperling <stsp@openbsd.org>
@@ -22171,12 +22171,27 @@ qwx_dp_tx(struct qwx_softc *sc, struct qwx_vif *arvif, uint8_t pdev_id,
 #endif
        ret = bus_dmamap_load_mbuf(sc->sc_dmat, tx_data->map,
            m, BUS_DMA_WRITE | BUS_DMA_NOWAIT);
-       if (ret) {
+       if (ret && ret != EFBIG) {
                printf("%s: failed to map Tx buffer: %d\n",
                    sc->sc_dev.dv_xname, ret);
                m_freem(m);
                return ret;
        }
+       if (ret) {
+               /* Too many DMA segments, linearize mbuf. */
+               if (m_defrag(m, M_DONTWAIT)) {
+                       m_freem(m);
+                       return ENOBUFS;
+               }
+               ret = bus_dmamap_load_mbuf(sc->sc_dmat, tx_data->map, m,
+                   BUS_DMA_NOWAIT | BUS_DMA_WRITE);
+               if (ret) {
+                       printf("%s: failed to map Tx buffer: %d\n",
+                           sc->sc_dev.dv_xname, ret);
+                       m_freem(m);
+                       return ret;
+               }
+       }
        ti.paddr = tx_data->map->dm_segs[0].ds_addr;
 
        ti.data_len = m->m_pkthdr.len;
@@ -22290,11 +22305,26 @@ qwx_mac_mgmt_tx_wmi(struct qwx_softc *sc, struct qwx_vif *arvif,
 #endif
        ret = bus_dmamap_load_mbuf(sc->sc_dmat, tx_data->map,
            m, BUS_DMA_WRITE | BUS_DMA_NOWAIT);
-       if (ret) {
+       if (ret && ret != EFBIG) {
                printf("%s: failed to map mgmt Tx buffer: %d\n",
                    sc->sc_dev.dv_xname, ret);
                return ret;
        }
+       if (ret) {
+               /* Too many DMA segments, linearize mbuf. */
+               if (m_defrag(m, M_DONTWAIT)) {
+                       m_freem(m);
+                       return ENOBUFS;
+               }
+               ret = bus_dmamap_load_mbuf(sc->sc_dmat, tx_data->map, m,
+                   BUS_DMA_NOWAIT | BUS_DMA_WRITE);
+               if (ret) {
+                       printf("%s: failed to map mgmt Tx buffer: %d\n",
+                           sc->sc_dev.dv_xname, ret);
+                       m_freem(m);
+                       return ret;
+               }
+       }
 
        ret = qwx_wmi_mgmt_send(sc, arvif, pdev_id, buf_id, m, tx_data);
        if (ret) {