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thunderbolt: stream: Unmap buffers with mapped size

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The size passed to dma_unmap_page() must match the size used for the
corresponding dma_map_page() call.

Stream RX and TX buffers are mapped with TB_MAX_FRAME_SIZE when the
buffer pools are allocated. However, tbstream_ring_free() currently uses
tb_ring_frame_size() as the unmap size.

That helper returns the current frame payload size, not the DMA mapping
size. On the TX path, tbstream_dev_alloc_tx() stores a shorter payload
length in frame.size when the payload is smaller than TB_MAX_FRAME_SIZE.
This happens for a short final DATA frame, and also for the CLOSE frame,
which is allocated with SZ_256.

In those cases the buffer was mapped with TB_MAX_FRAME_SIZE, but
tb_ring_frame_size() returns the shorter frame payload length. This makes
the dma_unmap_page() size differ from the original dma_map_page() size.

Use TB_MAX_FRAME_SIZE when unmapping stream buffers so the unmap size
matches the DMA mapping size used by the buffer allocation paths.

Signed-off-by: Xu Rao <raoxu@uniontech.com>
Fixes: 6db21d817b ("thunderbolt: Add support for USB4STREAM")
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
This commit is contained in:
Xu Rao 2026-06-11 14:45:30 +08:00 committed by Mika Westerberg
parent dc59e4fea9
commit 97b228e596
1 changed files with 1 additions and 1 deletions
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2
drivers/thunderbolt/stream.c
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@ -257,7 +257,7 @@ static void tbstream_ring_free(struct tbstream_ring *ring)
if (sf->frame.buffer_phy)
dma_unmap_page(dma_dev, sf->frame.buffer_phy,
tb_ring_frame_size(&sf->frame), dir);
TB_MAX_FRAME_SIZE, dir);
sf->frame.buffer_phy = 0;
if (sf->page)
__free_page(sf->page);