diff mbox series

[v3,wireless-drivers,2/2] mt76: dma: fix buffer unmap with non-linear skbs

Message ID b9c87448d9e5f3cf9cd5de5050f5c62e42c3de31.1572204430.git.lorenzo@kernel.org
State Awaiting Upstream
Delegated to: David Miller
Headers show
Series fix mt76x2e hangs on U7612E mini-pcie | expand

Commit Message

Lorenzo Bianconi Oct. 27, 2019, 7:53 p.m. UTC
mt76 dma layer is supposed to unmap skb data buffers while keep txwi
mapped on hw dma ring. At the moment mt76 wrongly unmap txwi or does
not unmap data fragments in even positions for non-linear skbs. This
issue may result in hw hangs with A-MSDU if the system relies on IOMMU
or SWIOTLB. Fix this behaviour properly unmapping data fragments on
non-linear skbs.

Fixes: 17f1de56df05 ("mt76: add common code shared between multiple chipsets")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/wireless/mediatek/mt76/dma.c  | 6 ++++--
 drivers/net/wireless/mediatek/mt76/mt76.h | 5 +++--
 2 files changed, 7 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/wireless/mediatek/mt76/dma.c b/drivers/net/wireless/mediatek/mt76/dma.c
index c747eb24581c..8f69d00bd940 100644
--- a/drivers/net/wireless/mediatek/mt76/dma.c
+++ b/drivers/net/wireless/mediatek/mt76/dma.c
@@ -53,8 +53,10 @@  mt76_dma_add_buf(struct mt76_dev *dev, struct mt76_queue *q,
 	u32 ctrl;
 	int i, idx = -1;
 
-	if (txwi)
+	if (txwi) {
 		q->entry[q->head].txwi = DMA_DUMMY_DATA;
+		q->entry[q->head].skip_buf0 = true;
+	}
 
 	for (i = 0; i < nbufs; i += 2, buf += 2) {
 		u32 buf0 = buf[0].addr, buf1 = 0;
@@ -97,7 +99,7 @@  mt76_dma_tx_cleanup_idx(struct mt76_dev *dev, struct mt76_queue *q, int idx,
 	__le32 __ctrl = READ_ONCE(q->desc[idx].ctrl);
 	u32 ctrl = le32_to_cpu(__ctrl);
 
-	if (!e->txwi || !e->skb) {
+	if (!e->skip_buf0) {
 		__le32 addr = READ_ONCE(q->desc[idx].buf0);
 		u32 len = FIELD_GET(MT_DMA_CTL_SD_LEN0, ctrl);
 
diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index dc468ed9434a..8aec7ccf2d79 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -93,8 +93,9 @@  struct mt76_queue_entry {
 		struct urb *urb;
 	};
 	enum mt76_txq_id qid;
-	bool schedule;
-	bool done;
+	bool skip_buf0:1;
+	bool schedule:1;
+	bool done:1;
 };
 
 struct mt76_queue_regs {