Commit 0354aec1 authored Dec 15, 2015 by Daniel Mentz Committed by Dan Williams Dec 16, 2015

dma-debug: Fix dma_debug_entry offset calculation



dma-debug uses struct dma_debug_entry to keep track of dma coherent
memory allocation requests. The virtual address is converted into a pfn
and an offset. Previously, the offset was calculated using an incorrect
bit mask.  As a result, we saw incorrect error messages from dma-debug
like the following:

"DMA-API: exceeded 7 overlapping mappings of cacheline 0x03e00000"

Cacheline 0x03e00000 does not exist on our platform.

Cc: <stable@vger.kernel.org>
Fixes: 0abdd7a8 ("dma-debug: introduce debug_dma_assert_idle()")
Signed-off-by: Daniel Mentz <danielmentz@google.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

parent 3e6110fd

lib/dma-debug.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1464,7 +1464,7 @@ void debug_dma_alloc_coherent(struct device *dev, size_t size,
		entry->type = dma_debug_coherent;
		entry->dev = dev;
		entry->pfn = page_to_pfn(virt_to_page(virt));
		entry->offset = (size_t) virt & PAGE_MASK;
		entry->offset = (size_t) virt & ~PAGE_MASK;
		entry->size = size;
		entry->dev_addr = dma_addr;
		entry->direction = DMA_BIDIRECTIONAL;
		@@ -1480,7 +1480,7 @@ void debug_dma_free_coherent(struct device *dev, size_t size,
		.type = dma_debug_coherent,
		.dev = dev,
		.pfn = page_to_pfn(virt_to_page(virt)),
		.offset = (size_t) virt & PAGE_MASK,
		.offset = (size_t) virt & ~PAGE_MASK,
		.dev_addr = addr,
		.size = size,
		.direction = DMA_BIDIRECTIONAL,

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