lib/dma-debug.c: fix incorrect pfn calculation
dma-debug reports the following warning:
WARNING: CPU: 3 PID: 298 at kernel-4.4/lib/dma-debug.c:604
debug _dma_assert_idle+0x1a8/0x230()
DMA-API: cpu touching an active dma mapped cacheline [cln=0x00000882300]
CPU: 3 PID: 298 Comm: vold Tainted: G W O 4.4.22+ #1
Hardware name: MT6739 (DT)
Call trace:
debug_dma_assert_idle+0x1a8/0x230
wp_page_copy.isra.96+0x118/0x520
do_wp_page+0x4fc/0x534
handle_mm_fault+0xd4c/0x1310
do_page_fault+0x1c8/0x394
do_mem_abort+0x50/0xec
I found that debug_dma_alloc_coherent() and debug_dma_free_coherent()
assume that dma_alloc_coherent() always returns a linear address.
However it's possible that dma_alloc_coherent() returns a non-linear
address. In this case, page_to_pfn(virt_to_page(virt)) will return an
incorrect pfn. If the pfn is valid and mapped as a COW page, we will
hit the warning when doing wp_page_copy().
Fix this by calculating pfn for linear and non-linear addresses.
[miles.chen@mediatek.com: v4]
Link: http://lkml.kernel.org/r/1510872972-23919-1-git-send-email-miles.chen@mediatek.com
Link: http://lkml.kernel.org/r/1506484087-1177-1-git-send-email-miles.chen@mediatek.com
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed