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dma-debug: New interfaces to debug dma mapping errors

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Add dma-debug interface debug_dma_mapping_error() to debug
drivers that fail to check dma mapping errors on addresses
returned by dma_map_single() and dma_map_page() interfaces.
This interface clears a flag set by debug_dma_map_page() to
indicate that dma_mapping_error() has been called by the
driver. When driver does unmap, debug_dma_unmap() checks the
flag and if this flag is still set, prints warning message
that includes call trace that leads up to the unmap. This
interface can be called from dma_mapping_error() routines to
enable dma mapping error check debugging.

Tested: Intel iommu and swiotlb (iommu=soft) on x86-64 with
        CONFIG_DMA_API_DEBUG enabled and disabled.

Signed-off-by: Shuah Khan <[email protected]>
Reviewed-by: Konrad Rzeszutek Wilk <[email protected]>
Signed-off-by: Joerg Roedel <[email protected]>
This commit is contained in:
Shuah Khan 2012-10-08 11:08:06 -06:00 • committed by Joerg Roedel
commit 6c9c6d6301
4 changed files with 87 additions and 4 deletions
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12
Documentation/DMA-API.txt
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@ -678,3 +678,15 @@ out of dma_debug_entries. These entries are preallocated at boot. The number
of preallocated entries is defined per architecture. If it is too low for you
boot with 'dma_debug_entries=<your_desired_number>' to overwrite the
architectural default.
void debug_dmap_mapping_error(struct device *dev, dma_addr_t dma_addr);
dma-debug interface debug_dma_mapping_error() to debug drivers that fail
to check dma mapping errors on addresses returned by dma_map_single() and
dma_map_page() interfaces. This interface clears a flag set by
debug_dma_map_page() to indicate that dma_mapping_error() has been called by
the driver. When driver does unmap, debug_dma_unmap() checks the flag and if
this flag is still set, prints warning message that includes call trace that
leads up to the unmap. This interface can be called from dma_mapping_error()
routines to enable dma mapping error check debugging.