s patch adds a Kconfig dependency on an MMU being available before CMA can be enabled. Without this patch, CMA can be enabled on an MMU-less system which can lead to issues. This was discovered during randconfig testing, in which CMA was enabled w/o MMU being enabled, leading to the following error: CC mm/migrate.o mm/migrate.c: In function ‘remove_migration_pte’: mm/migrate.c:134:3: error: implicit declaration of function ‘pmd_trans_huge’ [-Werror=implicit-function-declaration] if (pmd_trans_huge(*pmd)) ^ mm/migrate.c:137:3: error: implicit declaration of function ‘pte_offset_map’ [-Werror=implicit-function-declaration] ptep = pte_offset_map(pmd, addr); Signed-off-by: Manjunath Goudar <manjunath.goudar@xxxxxxxxxx> Acked-by: Arnd Bergmann <arnd@xxxxxxxxxx> Cc: Deepak Saxena <dsaxena@xxxxxxxxxx> Cc: IWAMOTO Toshihiro <iwamoto@xxxxxxxxxxxxx> Cc: Hirokazu Takahashi <taka@xxxxxxxxxxxxx> Cc: Dave Hansen <haveblue@xxxxxxxxxx> Cc: linux-mm@xxxxxxxxx Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxx> Cc: Balbir Singh <bsingharora@xxxxxxxxx> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> --- mm/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/Kconfig b/mm/Kconfig index 256bfd0..ad6b98e 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -522,7 +522,7 @@ config MEM_SOFT_DIRTY config CMA bool "Contiguous Memory Allocator" - depends on HAVE_MEMBLOCK + depends on MMU && HAVE_MEMBLOCK select MIGRATION select MEMORY_ISOLATION help -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>