From: Felix Fietkau <nbd@nbd.name>
Date: Mon, 20 Jan 2020 11:07:09 +0000 (+0100)
Subject: mt76: set dma-done flag for flushed descriptors
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5ffc6b5a98404db51529c427ccbccd4878593cea;p=linux.git

mt76: set dma-done flag for flushed descriptors

Avoids a theoretical corner case where the hardware could try to process
a stale descriptor after a watchdog reset

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

diff --git a/drivers/net/wireless/mediatek/mt76/dma.c b/drivers/net/wireless/mediatek/mt76/dma.c
index 9e03a7871ff44..e69329feed78a 100644
--- a/drivers/net/wireless/mediatek/mt76/dma.c
+++ b/drivers/net/wireless/mediatek/mt76/dma.c
@@ -246,7 +246,9 @@ mt76_dma_dequeue(struct mt76_dev *dev, struct mt76_queue *q, bool flush,
 	if (!q->queued)
 		return NULL;
 
-	if (!flush && !(q->desc[idx].ctrl & cpu_to_le32(MT_DMA_CTL_DMA_DONE)))
+	if (flush)
+		q->desc[idx].ctrl |= cpu_to_le32(MT_DMA_CTL_DMA_DONE);
+	else if (!(q->desc[idx].ctrl & cpu_to_le32(MT_DMA_CTL_DMA_DONE)))
 		return NULL;
 
 	q->tail = (q->tail + 1) % q->ndesc;