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Ensure that we only call the busdma unmap/flush routines once, when

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the buffer is being freed.

* When buffers are cloned, the original mapping isn't copied but it
  wasn't freeing the mapping until later.  To be safe, free the
  mapping when the buffer is cloned.

* ath_freebuf() now no longer calls the busdma sync/unmap routines.

* ath_tx_freebuf() now calls sync/unmap.

* Call sync first, before calling unmap.

Tested:

* AR5416, STA mode
This commit is contained in:
Adrian Chadd 2013-04-01 20:57:13 +00:00
parent 70d41b5846
commit 3f3a5dbd2c
3 changed files with 39 additions and 22 deletions
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49
sys/dev/ath/if_ath.c
View File

@ -2512,7 +2512,7 @@ _ath_getbuf_locked(struct ath_softc *sc, ath_buf_type_t btype)
* The caller must free the buffer using ath_freebuf().
*/
struct ath_buf *
ath_buf_clone(struct ath_softc *sc, const struct ath_buf *bf)
ath_buf_clone(struct ath_softc *sc, struct ath_buf *bf)
{
struct ath_buf *tbf;
@ -2528,14 +2528,6 @@ ath_buf_clone(struct ath_softc *sc, const struct ath_buf *bf)
tbf->bf_flags = bf->bf_flags & ATH_BUF_FLAGS_CLONE;
tbf->bf_status = bf->bf_status;
tbf->bf_m = bf->bf_m;
/*
* XXX Copy the node reference, the caller is responsible
* for deleting the node reference before it frees its
* buffer.
*
* XXX It's done like this so we don't call the net80211
* code whilst having active TX queue locks held.
*/
tbf->bf_node = bf->bf_node;
/* will be setup by the chain/setup function */
tbf->bf_lastds = NULL;
@ -2547,6 +2539,23 @@ ath_buf_clone(struct ath_softc *sc, const struct ath_buf *bf)
/* The caller has to re-init the descriptor + links */
/*
* Free the DMA mapping here, before we NULL the mbuf.
* We must only call bus_dmamap_unload() once per mbuf chain
* or behaviour is undefined.
*/
if (bf->bf_m != NULL) {
/*
* XXX is this POSTWRITE call required?
*/
bus_dmamap_sync(sc->sc_dmat, bf->bf_dmamap,
BUS_DMASYNC_POSTWRITE);
bus_dmamap_unload(sc->sc_dmat, bf->bf_dmamap);
}
bf->bf_m = NULL;
bf->bf_node = NULL;
/* Copy state */
memcpy(&tbf->bf_state, &bf->bf_state, sizeof(bf->bf_state));
@ -4220,9 +4229,6 @@ ath_txq_addholdingbuf(struct ath_softc *sc, struct ath_buf *bf)
void
ath_freebuf(struct ath_softc *sc, struct ath_buf *bf)
{
bus_dmamap_unload(sc->sc_dmat, bf->bf_dmamap);
bus_dmamap_sync(sc->sc_dmat, bf->bf_dmamap, BUS_DMASYNC_POSTWRITE);
KASSERT((bf->bf_node == NULL), ("%s: bf->bf_node != NULL\n", __func__));
KASSERT((bf->bf_m == NULL), ("%s: bf->bf_m != NULL\n", __func__));
@ -4256,6 +4262,17 @@ ath_tx_freebuf(struct ath_softc *sc, struct ath_buf *bf, int status)
struct ieee80211_node *ni = bf->bf_node;
struct mbuf *m0 = bf->bf_m;
/*
* Make sure that we only sync/unload if there's an mbuf.
* If not (eg we cloned a buffer), the unload will have already
* occured.
*/
if (bf->bf_m != NULL) {
bus_dmamap_sync(sc->sc_dmat, bf->bf_dmamap,
BUS_DMASYNC_POSTWRITE);
bus_dmamap_unload(sc->sc_dmat, bf->bf_dmamap);
}
bf->bf_node = NULL;
bf->bf_m = NULL;
@ -4270,13 +4287,9 @@ ath_tx_freebuf(struct ath_softc *sc, struct ath_buf *bf, int status)
ieee80211_process_callback(ni, m0, status);
ieee80211_free_node(ni);
}
m_freem(m0);
/*
* XXX the buffer used to be freed -after-, but the DMA map was
* freed where ath_freebuf() now is. I've no idea what this
* will do.
*/
/* Finally, we don't need this mbuf any longer */
m_freem(m0);
}
static struct ath_buf *

2
sys/dev/ath/if_ath_misc.h
View File

@ -59,7 +59,7 @@ extern struct ath_buf * ath_getbuf(struct ath_softc *sc,
extern struct ath_buf * _ath_getbuf_locked(struct ath_softc *sc,
ath_buf_type_t btype);
extern struct ath_buf * ath_buf_clone(struct ath_softc *sc,
const struct ath_buf *bf);
struct ath_buf *bf);
/* XXX change this to NULL the buffer pointer? */
extern void ath_freebuf(struct ath_softc *sc, struct ath_buf *bf);
extern void ath_returnbuf_head(struct ath_softc *sc, struct ath_buf *bf);

10
sys/dev/ath/if_ath_tx.c
View File

@ -3842,6 +3842,12 @@ ath_tx_retry_clone(struct ath_softc *sc, struct ath_node *an,
struct ath_buf *nbf;
int error;
/*
* Clone the buffer. This will handle the dma unmap and
* copy the node reference to the new buffer. If this
* works out, 'bf' will have no DMA mapping, no mbuf
* pointer and no node reference.
*/
nbf = ath_buf_clone(sc, bf);
#if 0
@ -3879,9 +3885,7 @@ ath_tx_retry_clone(struct ath_softc *sc, struct ath_node *an,
if (bf->bf_state.bfs_dobaw)
ath_tx_switch_baw_buf(sc, an, tid, bf, nbf);
/* Free current buffer; return the older buffer */
bf->bf_m = NULL;
bf->bf_node = NULL;
/* Free original buffer; return new buffer */
ath_freebuf(sc, bf);
return nbf;