Re: [PATCH 2/3] mm/sparse: expand the CONFIG_SPARSEMEM_EXTREME range in __nr_to_section()
From: Michal Hocko <mhocko@suse.com>
Date: 2018-08-23 13:21:16
[Cc Dave] On Thu 23-08-18 21:07:31, Wei Yang wrote:
When CONFIG_SPARSEMEM_EXTREME is not defined, mem_section is a static two dimension array. This means !mem_section[SECTION_NR_TO_ROOT(nr)] is always true. This patch expand the CONFIG_SPARSEMEM_EXTREME range to return a proper mem_section when CONFIG_SPARSEMEM_EXTREME is not defined.
As long as all callers provide a valid section number then yes. I am not really sure this is the case though.
quoted hunk ↗ jump to hunk
Signed-off-by: Wei Yang <redacted> --- include/linux/mmzone.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 32699b2dc52a..33086f86d1a7 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h@@ -1155,9 +1155,9 @@ static inline struct mem_section *__nr_to_section(unsigned long nr) #ifdef CONFIG_SPARSEMEM_EXTREME if (!mem_section) return NULL; -#endif if (!mem_section[SECTION_NR_TO_ROOT(nr)]) return NULL; +#endif return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK]; } extern int __section_nr(struct mem_section* ms);-- 2.15.1
-- Michal Hocko SUSE Labs