On Mon, 2013-03-18 at 15:12 -0700, Alexander Duyck wrote: > 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 <[email protected]> > ---
Looks good. Tested it as well. Reviewed-by: [email protected] Tested-by: [email protected] Thanks for finding and fixing the problem. -- Shuah -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
