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Some TX dmamap cleanups.

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* Don't use BUS_DMA_ALLOCNOW for descriptor DMA maps; we never use
  bounce buffers for the descriptors themselves.

* Add some XXX's to mark where the ath_buf has its mbuf ripped from
  underneath it without actually cleaning up the dmamap.  I haven't
  audited those particular code paths to see if the DMA map is guaranteed
  to be setup there; I'll do that later.

* Print out a warning if the descdma tidyup code is given some descriptors
  w/ maps to free.  Ideally the owner will free the mbufs and unmap
  the descriptors before freeing the descriptor/ath_buf pairs, but
  right now that's not guaranteed to be done.

Reviewed by:	scottl (BUS_DMA_ALLOCNOW tag)
This commit is contained in:
Adrian Chadd 2013-04-02 06:24:22 +00:00
parent 18303fd833
commit a91ab3c099
1 changed files with 23 additions and 1 deletions
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24
sys/dev/ath/if_ath.c
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@ -2742,6 +2742,7 @@ ath_start(struct ifnet *ifp)
"%s: flush fragmented packet, state %s\n",
__func__,
ieee80211_state_name[ni->ni_vap->iv_state]);
/* XXX dmamap */
ath_freetx(next);
goto reclaim;
}
@ -3031,6 +3032,9 @@ ath_descdma_alloc_desc(struct ath_softc *sc,
/*
* Setup DMA descriptor area.
*
* BUS_DMA_ALLOCNOW is not used; we never use bounce
* buffers for the descriptors themselves.
*/
error = bus_dma_tag_create(bus_get_dma_tag(sc->sc_dev), /* parent */
PAGE_SIZE, 0, /* alignment, bounds */
@ -3040,7 +3044,7 @@ ath_descdma_alloc_desc(struct ath_softc *sc,
dd->dd_desc_len, /* maxsize */
1, /* nsegments */
dd->dd_desc_len, /* maxsegsize */
BUS_DMA_ALLOCNOW, /* flags */
0, /* flags */
NULL, /* lockfunc */
NULL, /* lockarg */
&dd->dd_dmat);
@ -3237,6 +3241,7 @@ ath_descdma_cleanup(struct ath_softc *sc,
{
struct ath_buf *bf;
struct ieee80211_node *ni;
int do_warning = 0;
if (dd->dd_dmamap != 0) {
bus_dmamap_unload(dd->dd_dmat, dd->dd_dmamap);
@ -3247,6 +3252,23 @@ ath_descdma_cleanup(struct ath_softc *sc,
if (head != NULL) {
TAILQ_FOREACH(bf, head, bf_list) {
if (bf->bf_m) {
/*
* XXX warn if there's buffers here.
* XXX it should have been freed by the
* owner!
*/
if (do_warning == 0) {
do_warning = 1;
device_printf(sc->sc_dev,
"%s: %s: mbuf should've been"
" unmapped/freed!\n",
__func__,
dd->dd_name);
}
bus_dmamap_sync(sc->sc_dmat, bf->bf_dmamap,
BUS_DMASYNC_POSTREAD);
bus_dmamap_unload(sc->sc_dmat, bf->bf_dmamap);
m_freem(bf->bf_m);
bf->bf_m = NULL;
}