]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
ARM: CMA: avoid double mapping to the CMA area if CONFIG_HIGHMEM=y
authorJoonsoo Kim <iamjoonsoo.kim@lge.com>
Tue, 10 Apr 2018 23:30:23 +0000 (16:30 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 11 Apr 2018 17:28:32 +0000 (10:28 -0700)
commit3d2054ad8c2d5100b68b0c0405f89fd90bf4107b
treeb8dd3671bb016515084e4f9a63cf66589f0cbe15
parent1d47a3ec09b5489cd915e8f492aa623cdab5d002
ARM: CMA: avoid double mapping to the CMA area if CONFIG_HIGHMEM=y

CMA area is now managed by the separate zone, ZONE_MOVABLE, to fix many
MM related problems.  In this implementation, if CONFIG_HIGHMEM = y,
then ZONE_MOVABLE is considered as HIGHMEM and the memory of the CMA
area is also considered as HIGHMEM.  That means that they are considered
as the page without direct mapping.  However, CMA area could be in a
lowmem and the memory could have direct mapping.

In ARM, when establishing a new mapping for DMA, direct mapping should
be cleared since two mapping with different cache policy could cause
unknown problem.  With this patch, PageHighmem() for the CMA memory
located in lowmem returns true so that the function for DMA mapping
cannot notice whether it needs to clear direct mapping or not,
correctly.  To handle this situation, this patch always clears direct
mapping for such CMA memory.

Link: http://lkml.kernel.org/r/1512114786-5085-4-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/arm/mm/dma-mapping.c