From 99ba6a4610c8413c9166e600b1797f0a8f1c4498 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Mon, 8 Apr 2013 00:04:13 +0200 Subject: [PATCH] ath9k: implement buffer holding handling for EDMA FIFO Inside one FIFO slot queue, EDMA chipsets have the same link pointer re-read race condition as older chipsets, so the same buffer holding logic needs to be used in order to avoid use-after-free bugs. Unlike on older chips, it can be skipped for the end of the queue. Signed-off-by: Felix Fietkau Signed-off-by: John W. Linville --- drivers/net/wireless/ath/ath9k/xmit.c | 30 +++++++++++++++++---------- 1 file changed, 19 insertions(+), 11 deletions(-) diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c index 94b2ee1220db..5bc580276493 100644 --- a/drivers/net/wireless/ath/ath9k/xmit.c +++ b/drivers/net/wireless/ath/ath9k/xmit.c @@ -516,8 +516,7 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq, * not a holding desc. */ INIT_LIST_HEAD(&bf_head); - if ((sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) || - bf_next != NULL || !bf_last->bf_stale) + if (bf_next != NULL || !bf_last->bf_stale) list_move_tail(&bf->list, &bf_head); if (!txpending || (tid->state & AGGR_CLEANUP)) { @@ -537,8 +536,7 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq, !txfail); } else { /* retry the un-acked ones */ - if (!(sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) && - bf->bf_next == NULL && bf_last->bf_stale) { + if (bf->bf_next == NULL && bf_last->bf_stale) { struct ath_buf *tbf; tbf = ath_clone_txbuf(sc, bf_last); @@ -2264,6 +2262,7 @@ void ath_tx_edma_tasklet(struct ath_softc *sc) struct ath_txq *txq; struct ath_buf *bf, *lastbf; struct list_head bf_head; + struct list_head *fifo_list; int status; for (;;) { @@ -2291,20 +2290,24 @@ void ath_tx_edma_tasklet(struct ath_softc *sc) TX_STAT_INC(txq->axq_qnum, txprocdesc); - if (list_empty(&txq->txq_fifo[txq->txq_tailidx])) { + fifo_list = &txq->txq_fifo[txq->txq_tailidx]; + if (list_empty(fifo_list)) { ath_txq_unlock(sc, txq); return; } - bf = list_first_entry(&txq->txq_fifo[txq->txq_tailidx], - struct ath_buf, list); + bf = list_first_entry(fifo_list, struct ath_buf, list); + if (bf->bf_stale) { + list_del(&bf->list); + ath_tx_return_buffer(sc, bf); + bf = list_first_entry(fifo_list, struct ath_buf, list); + } + lastbf = bf->bf_lastbf; INIT_LIST_HEAD(&bf_head); - list_cut_position(&bf_head, &txq->txq_fifo[txq->txq_tailidx], - &lastbf->list); - - if (list_empty(&txq->txq_fifo[txq->txq_tailidx])) { + if (list_is_last(&lastbf->list, fifo_list)) { + list_splice_tail_init(fifo_list, &bf_head); INCR(txq->txq_tailidx, ATH_TXFIFO_DEPTH); if (!list_empty(&txq->axq_q)) { @@ -2315,6 +2318,11 @@ void ath_tx_edma_tasklet(struct ath_softc *sc) list_splice_tail_init(&txq->axq_q, &bf_q); ath_tx_txqaddbuf(sc, txq, &bf_q, true); } + } else { + lastbf->bf_stale = true; + if (bf != lastbf) + list_cut_position(&bf_head, fifo_list, + lastbf->list.prev); } ath_tx_process_buffer(sc, txq, &ts, bf, &bf_head); -- 2.30.2