common: DMA-mapping: add DMA_ATTR_NO_KERNEL_MAPPING attribute
authorMarek Szyprowski <m.szyprowski@samsung.com>
Wed, 16 May 2012 13:20:37 +0000 (15:20 +0200)
committerGrazvydas Ignotas <notasas@gmail.com>
Sat, 2 Mar 2013 20:11:37 +0000 (22:11 +0200)
commit605eefe85896b4988dfcb476ef71df188db9b9de
treed92bda02a8b434c9d2d49c958a99e86204adff9d
parent509287353b1766e719c983be2d653bcb2b8e5244
common: DMA-mapping: add DMA_ATTR_NO_KERNEL_MAPPING attribute

This patch adds DMA_ATTR_NO_KERNEL_MAPPING attribute which lets the
platform to avoid creating a kernel virtual mapping for the allocated
buffer. On some architectures creating such mapping is non-trivial task
and consumes very limited resources (like kernel virtual address space
or dma consistent address space). Buffers allocated with this attribute
can be only passed to user space by calling dma_mmap_attrs().

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Documentation/DMA-attributes.txt
include/linux/dma-attrs.h