mm/page_ext: remove rollback for untouched mem_section in online_page_ext

If init_section_page_ext failed, we only need rollback for mem_section
before failed mem_section.  Make rollback end point to failed mem_section
to remove unnecessary rollback.

As pfn += PAGES_PER_SECTION will be executed even if init_section_page_ext
failed.  So pfn points to mem_section after failed mem_section.  Subtract
one mem_section from pfn to get failed mem_section.

Link: https://lkml.kernel.org/r/20230714114749.1743032-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/page_ext.c b/mm/page_ext.c
index 096451d..f052397 100644 (file)
--- a/mm/page_ext.c
+++ b/mm/page_ext.c
@@ -424,6 +424,7 @@ static int __meminit online_page_ext(unsigned long start_pfn,
                return 0;
 
        /* rollback */
+       end = pfn - PAGES_PER_SECTION;
        for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
                __free_page_ext(pfn);