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: 0abdd7a81b7e ("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>

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 8855f019ebe8a61957795b0d5f5c3339fe180f5a..d34bd24c2c84779c38c300f470b22df52e76cb58 100644 (file)
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -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,