CMA: generalize CMA reserved area management functionality
authorJoonsoo Kim <iamjoonsoo.kim@lge.com>
Wed, 6 Aug 2014 23:05:25 +0000 (16:05 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 7 Aug 2014 01:01:16 +0000 (18:01 -0700)
commita254129e8686bff7a340b58f35241b04927e81c0
tree90828b720ab7221a0f13c2fe3b15f997e64ea0c3
parente0bdb37d95dd44086159607e571fd70f6b62dc2d
CMA: generalize CMA reserved area management functionality

Currently, there are two users on CMA functionality, one is the DMA
subsystem and the other is the KVM on powerpc.  They have their own code
to manage CMA reserved area even if they looks really similar.  From my
guess, it is caused by some needs on bitmap management.  KVM side wants
to maintain bitmap not for 1 page, but for more size.  Eventually it use
bitmap where one bit represents 64 pages.

When I implement CMA related patches, I should change those two places
to apply my change and it seem to be painful to me.  I want to change
this situation and reduce future code management overhead through this
patch.

This change could also help developer who want to use CMA in their new
feature development, since they can use CMA easily without copying &
pasting this reserved area management code.

In previous patches, we have prepared some features to generalize CMA
reserved area management and now it's time to do it.  This patch moves
core functions to mm/cma.c and change DMA APIs to use these functions.

There is no functional change in DMA APIs.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/arm/mm/dma-mapping.c
drivers/base/Kconfig
drivers/base/dma-contiguous.c
include/linux/cma.h [new file with mode: 0644]
include/linux/dma-contiguous.h
mm/Kconfig
mm/Makefile
mm/cma.c [new file with mode: 0644]