From 6cdadd4dc7621e47739a84548e70713e157fa850 Mon Sep 17 00:00:00 2001 From: Vladimir Kondratiev Date: Thu, 11 Jul 2013 18:03:41 +0300 Subject: [PATCH] wil6210: fix subtle race in wil_tx_vring Finish all SW context modifications prior to notifying hardware It used to be race condition: if HW finish Tx and issue Tx completion IRQ very fast, prior to SW context update in wil_tx_vring, Tx completion will mis-handle descriptor, as SW part will have no skb pointer stored. Signed-off-by: Vladimir Kondratiev Signed-off-by: John W. Linville --- drivers/net/wireless/ath/wil6210/txrx.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/net/wireless/ath/wil6210/txrx.c b/drivers/net/wireless/ath/wil6210/txrx.c index 44cdd2a3dff3..2a9d56a5fd0c 100644 --- a/drivers/net/wireless/ath/wil6210/txrx.c +++ b/drivers/net/wireless/ath/wil6210/txrx.c @@ -712,6 +712,12 @@ static int wil_tx_vring(struct wil6210_priv *wil, struct vring *vring, d->dma.d0 |= BIT(DMA_CFG_DESC_TX_0_CMD_DMA_IT_POS); *_d = *d; + /* hold reference to skb + * to prevent skb release before accounting + * in case of immediate "tx done" + */ + vring->ctx[i].skb = skb_get(skb); + wil_hex_dump_txrx("Tx ", DUMP_PREFIX_NONE, 32, 4, (const void *)d, sizeof(*d), false); @@ -720,11 +726,6 @@ static int wil_tx_vring(struct wil6210_priv *wil, struct vring *vring, wil_dbg_txrx(wil, "Tx swhead %d -> %d\n", swhead, vring->swhead); trace_wil6210_tx(vring_index, swhead, skb->len, nr_frags); iowrite32(vring->swhead, wil->csr + HOSTADDR(vring->hwtail)); - /* hold reference to skb - * to prevent skb release before accounting - * in case of immediate "tx done" - */ - vring->ctx[i].skb = skb_get(skb); return 0; dma_error: -- 2.20.1