From f2be00b1011ab791ef2a4688c1f65eab7765c398 Mon Sep 17 00:00:00 2001 From: Lorenzo Bianconi Date: Sun, 27 Oct 2019 20:53:09 +0100 Subject: [PATCH] mt76: dma: fix buffer unmap with non-linear skbs 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 --- dma.c | 6 ++++-- mt76.h | 5 +++-- 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/dma.c b/dma.c index 4da7cffb..3de744fb 100644 --- a/dma.c +++ b/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/mt76.h b/mt76.h index a3e89728..4bdf8c44 100644 --- a/mt76.h +++ b/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 {