Date: Wed, 8 May 2013 21:23:51 +0000 (UTC) From: Adrian Chadd <adrian@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r250391 - head/sys/dev/ath Message-ID: <201305082123.r48LNpw9091035@svn.freebsd.org>
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Author: adrian Date: Wed May 8 21:23:51 2013 New Revision: 250391 URL: http://svnweb.freebsd.org/changeset/base/250391 Log: Fix the holding descriptor logic to actually be "right" (for values of "right".) Flip back on the "always continue TX DMA using the holding descriptor" code - by always setting ATH_BUF_BUSY and never setting axq_link to NULL. Since the holding descriptor is accessed via txq->axq_link and _that_ is done behind the TXQ lock rather than the TX path lock, the holding descriptor stuff itself needs to be behind the TXQ lock. So, do the mental gymnastics needed to do this. I've not seen any of the hardware failures that I was seeing when I last tried to do this. Tested: * AR5416, STA mode Modified: head/sys/dev/ath/if_ath.c head/sys/dev/ath/if_athvar.h Modified: head/sys/dev/ath/if_ath.c ============================================================================== --- head/sys/dev/ath/if_ath.c Wed May 8 21:07:11 2013 (r250390) +++ head/sys/dev/ath/if_ath.c Wed May 8 21:23:51 2013 (r250391) @@ -3896,6 +3896,7 @@ ath_tx_process_buf_completion(struct ath struct ath_node *an = NULL; ATH_TX_UNLOCK_ASSERT(sc); + ATH_TXQ_UNLOCK_ASSERT(txq); /* If unicast frame, update general statistics */ if (ni != NULL) { @@ -4000,6 +4001,28 @@ ath_tx_processq(struct ath_softc *sc, st break; } ATH_TXQ_REMOVE(txq, bf, bf_list); + + /* + * Sanity check. + */ + if (txq->axq_qnum != bf->bf_state.bfs_tx_queue) { + device_printf(sc->sc_dev, + "%s: TXQ=%d: bf=%p, bfs_tx_queue=%d\n", + __func__, + txq->axq_qnum, + bf, + bf->bf_state.bfs_tx_queue); + } + if (txq->axq_qnum != bf->bf_last->bf_state.bfs_tx_queue) { + device_printf(sc->sc_dev, + "%s: TXQ=%d: bf_last=%p, bfs_tx_queue=%d\n", + __func__, + txq->axq_qnum, + bf->bf_last, + bf->bf_last->bf_state.bfs_tx_queue); + } + +#if 0 if (txq->axq_depth > 0) { /* * More frames follow. Mark the buffer busy @@ -4013,6 +4036,9 @@ ath_tx_processq(struct ath_softc *sc, st bf->bf_last->bf_flags |= ATH_BUF_BUSY; } else txq->axq_link = NULL; +#else + bf->bf_last->bf_flags |= ATH_BUF_BUSY; +#endif if (bf->bf_state.bfs_aggr) txq->axq_aggr_depth--; @@ -4288,13 +4314,18 @@ ath_returnbuf_head(struct ath_softc *sc, void ath_txq_freeholdingbuf(struct ath_softc *sc, struct ath_txq *txq) { - ATH_TXBUF_LOCK_ASSERT(sc); + ATH_TXBUF_UNLOCK_ASSERT(sc); + ATH_TXQ_LOCK_ASSERT(txq); if (txq->axq_holdingbf == NULL) return; txq->axq_holdingbf->bf_flags &= ~ATH_BUF_BUSY; + + ATH_TXBUF_LOCK(sc); ath_returnbuf_tail(sc, txq->axq_holdingbf); + ATH_TXBUF_UNLOCK(sc); + txq->axq_holdingbf = NULL; } @@ -4307,7 +4338,10 @@ ath_txq_addholdingbuf(struct ath_softc * { struct ath_txq *txq; - ATH_TXBUF_LOCK_ASSERT(sc); + txq = &sc->sc_txq[bf->bf_state.bfs_tx_queue]; + + ATH_TXBUF_UNLOCK_ASSERT(sc); + ATH_TXQ_LOCK_ASSERT(txq); /* XXX assert ATH_BUF_BUSY is set */ @@ -4321,7 +4355,6 @@ ath_txq_addholdingbuf(struct ath_softc * ath_returnbuf_tail(sc, bf); return; } - txq = &sc->sc_txq[bf->bf_state.bfs_tx_queue]; ath_txq_freeholdingbuf(sc, txq); txq->axq_holdingbf = bf; } @@ -4336,20 +4369,30 @@ ath_txq_addholdingbuf(struct ath_softc * * for restart (eg for TDMA.) * * The caller must free the mbuf and recycle the node reference. + * + * XXX This method of handling busy / holding buffers is insanely stupid. + * It requires bf_state.bfs_tx_queue to be correctly assigned. It would + * be much nicer if buffers in the processq() methods would instead be + * always completed there (pushed onto a txq or ath_bufhead) so we knew + * exactly what hardware queue they came from in the first place. */ void ath_freebuf(struct ath_softc *sc, struct ath_buf *bf) { + struct ath_txq *txq; + + txq = &sc->sc_txq[bf->bf_state.bfs_tx_queue]; + KASSERT((bf->bf_node == NULL), ("%s: bf->bf_node != NULL\n", __func__)); KASSERT((bf->bf_m == NULL), ("%s: bf->bf_m != NULL\n", __func__)); /* - * If this buffer is busy, push it onto the holding queue + * If this buffer is busy, push it onto the holding queue. */ if (bf->bf_flags & ATH_BUF_BUSY) { - ATH_TXBUF_LOCK(sc); + ATH_TXQ_LOCK(txq); ath_txq_addholdingbuf(sc, bf); - ATH_TXBUF_UNLOCK(sc); + ATH_TXQ_UNLOCK(txq); return; } @@ -4521,9 +4564,9 @@ ath_tx_draintxq(struct ath_softc *sc, st /* * Free the holding buffer if it exists */ - ATH_TXBUF_LOCK(sc); + ATH_TXQ_LOCK(txq); ath_txq_freeholdingbuf(sc, txq); - ATH_TXBUF_UNLOCK(sc); + ATH_TXQ_UNLOCK(txq); /* * Drain software queued frames which are on Modified: head/sys/dev/ath/if_athvar.h ============================================================================== --- head/sys/dev/ath/if_athvar.h Wed May 8 21:07:11 2013 (r250390) +++ head/sys/dev/ath/if_athvar.h Wed May 8 21:23:51 2013 (r250391) @@ -381,6 +381,8 @@ struct ath_txq { #define ATH_TXQ_LOCK(_tq) mtx_lock(&(_tq)->axq_lock) #define ATH_TXQ_UNLOCK(_tq) mtx_unlock(&(_tq)->axq_lock) #define ATH_TXQ_LOCK_ASSERT(_tq) mtx_assert(&(_tq)->axq_lock, MA_OWNED) +#define ATH_TXQ_UNLOCK_ASSERT(_tq) mtx_assert(&(_tq)->axq_lock, \ + MA_NOTOWNED) #define ATH_NODE_LOCK(_an) mtx_lock(&(_an)->an_mtx) @@ -964,6 +966,8 @@ struct ath_softc { #define ATH_TXBUF_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_txbuflock) #define ATH_TXBUF_LOCK_ASSERT(_sc) \ mtx_assert(&(_sc)->sc_txbuflock, MA_OWNED) +#define ATH_TXBUF_UNLOCK_ASSERT(_sc) \ + mtx_assert(&(_sc)->sc_txbuflock, MA_NOTOWNED) #define ATH_TXSTATUS_LOCK_INIT(_sc) do { \ snprintf((_sc)->sc_txcompname, sizeof((_sc)->sc_txcompname), \
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