diff options
author | Alexander Duyck <alexander.h.duyck@intel.com> | 2013-03-23 02:04:49 +0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-03-23 03:41:20 +0400 |
commit | 96e7d7a1e0fc7780b4c1981c787e42473aa91a95 (patch) | |
tree | dcb32597569f7b45ba48ae28c717f79661c0ff17 /mm/memory_hotplug.c | |
parent | 8d640a51ec9e9cdefa680b67ad55f933eefc5923 (diff) |
dma-debug: update DMA debug API to better handle multiple mappings of a buffer
There were reports of the igb driver unmapping buffers without calling
dma_mapping_error. On closer inspection issues were found in the DMA
debug API and how it handled multiple mappings of the same buffer.
The issue I found is the fact that the debug_dma_mapping_error would
only set the map_err_type to MAP_ERR_CHECKED in the case that the was
only one match for device and device address. However in the case of
non-IOMMU, multiple addresses existed and as a result it was not setting
this field once a second mapping was instantiated. I have resolved this
by changing the search so that it instead will now set MAP_ERR_CHECKED
on the first buffer that matches the device and DMA address that is
currently in the state MAP_ERR_NOT_CHECKED.
A secondary side effect of this patch is that in the case of multiple
buffers using the same address only the last mapping will have a valid
map_err_type. The previous mappings will all end up with map_err_type
set to MAP_ERR_CHECKED because of the dma_mapping_error call in
debug_dma_map_page. However this behavior may be preferable as it means
you will likely only see one real error per multi-mapped buffer, versus
the current behavior of multiple false errors mer multi-mapped buffer.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Reviewed-by: Shuah Khan <shuah.khan@hp.com>
Tested-by: Shuah Khan <shuah.khan@hp.com>
Cc: Jakub Kicinski <kubakici@wp.pl>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory_hotplug.c')
0 files changed, 0 insertions, 0 deletions