[PATCH RFC v4 38/42] kmsan: dma: unpoison memory mapped by dma_direct_map_page()

[glider@google.com]

KMSAN doesn't know about DMA memory writes performed by devices.
We unpoison such memory when it's mapped to avoid false positive
reports.

Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: linux-mm@kvack.org
---

Change-Id: Ib1019ed531fea69f88b5cdec3d1e27403f2f3d64
---
 kernel/dma/direct.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 6af7ae83c4ad..19d6d7dd10ec 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -376,6 +376,7 @@ dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
 		report_addr(dev, dma_addr, size);
 		return DMA_MAPPING_ERROR;
 	}
+	kmsan_handle_dma(page_address(page) + offset, size, dir);
 
 	if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 		arch_sync_dma_for_device(phys, size, dir);
-- 
2.24.1.735.g03f4e72817-goog