diff options
| author | Felix Fietkau <nbd@openwrt.org> | 2013-08-10 15:59:15 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-10-26 21:05:58 +0100 |
| commit | 42cb87a101c3fd0e080e9605ee70275efdcc8280 (patch) | |
| tree | 06ca210e7543b962d67a81309d03aab794313127 /drivers/net/wireless | |
| parent | f4dc9ffcb6227d10335af8be77c0f9a1a43f2578 (diff) | |
ath9k: fix rx descriptor related race condition
commit e96542e55a2aacf4bdeccfe2f17b77c4895b4df2 upstream.
Similar to a race condition that exists in the tx path, the hardware
might re-read the 'next' pointer of a descriptor of the last completed
frame. This only affects non-EDMA (pre-AR93xx) devices.
To deal with this race, defer clearing and re-linking a completed rx
descriptor until the next one has been processed.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'drivers/net/wireless')
| -rw-r--r-- | drivers/net/wireless/ath/ath9k/ath9k.h | 5 | ||||
| -rw-r--r-- | drivers/net/wireless/ath/ath9k/recv.c | 17 |
2 files changed, 14 insertions, 8 deletions
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h index 1c269f50822b..7c70cf2b5d1a 100644 --- a/drivers/net/wireless/ath/ath9k/ath9k.h +++ b/drivers/net/wireless/ath/ath9k/ath9k.h @@ -77,10 +77,6 @@ struct ath_config { sizeof(struct ath_buf_state)); \ } while (0) -#define ATH_RXBUF_RESET(_bf) do { \ - (_bf)->bf_stale = false; \ - } while (0) - /** * enum buffer_type - Buffer type flags * @@ -308,6 +304,7 @@ struct ath_rx { struct ath_buf *rx_bufptr; struct ath_rx_edma rx_edma[ATH9K_RX_QUEUE_MAX]; + struct ath_buf *buf_hold; struct sk_buff *frag; }; diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c index d171a7242e4a..8326c1402ea7 100644 --- a/drivers/net/wireless/ath/ath9k/recv.c +++ b/drivers/net/wireless/ath/ath9k/recv.c @@ -78,8 +78,6 @@ static void ath_rx_buf_link(struct ath_softc *sc, struct ath_buf *bf) struct ath_desc *ds; struct sk_buff *skb; - ATH_RXBUF_RESET(bf); - ds = bf->bf_desc; ds->ds_link = 0; /* link to null */ ds->ds_data = bf->bf_buf_addr; @@ -106,6 +104,14 @@ static void ath_rx_buf_link(struct ath_softc *sc, struct ath_buf *bf) sc->rx.rxlink = &ds->ds_link; } +static void ath_rx_buf_relink(struct ath_softc *sc, struct ath_buf *bf) +{ + if (sc->rx.buf_hold) + ath_rx_buf_link(sc, sc->rx.buf_hold); + + sc->rx.buf_hold = bf; +} + static void ath_setdefantenna(struct ath_softc *sc, u32 antenna) { /* XXX block beacon interrupts */ @@ -153,7 +159,6 @@ static bool ath_rx_edma_buf_link(struct ath_softc *sc, skb = bf->bf_mpdu; - ATH_RXBUF_RESET(bf); memset(skb->data, 0, ah->caps.rx_status_len); dma_sync_single_for_device(sc->dev, bf->bf_buf_addr, ah->caps.rx_status_len, DMA_TO_DEVICE); @@ -492,6 +497,7 @@ int ath_startrecv(struct ath_softc *sc) if (list_empty(&sc->rx.rxbuf)) goto start_recv; + sc->rx.buf_hold = NULL; sc->rx.rxlink = NULL; list_for_each_entry_safe(bf, tbf, &sc->rx.rxbuf, list) { ath_rx_buf_link(sc, bf); @@ -742,6 +748,9 @@ static struct ath_buf *ath_get_next_rx_buf(struct ath_softc *sc, } bf = list_first_entry(&sc->rx.rxbuf, struct ath_buf, list); + if (bf == sc->rx.buf_hold) + return NULL; + ds = bf->bf_desc; /* @@ -1974,7 +1983,7 @@ requeue: if (edma) { ath_rx_edma_buf_link(sc, qtype); } else { - ath_rx_buf_link(sc, bf); + ath_rx_buf_relink(sc, bf); ath9k_hw_rxena(ah); } } while (1); |