[PATCH 1/2] mm,sparse: Fix deactivate_section for early sections

From: Oscar Salvador
Date: Mon Jul 15 2019 - 04:16:06 EST


deactivate_section checks whether a section is early or not
in order to either call free_map_bootmem() or depopulate_section_memmap().
Being the former for sections added at boot time, and the latter for
sections hotplugged.

The problem is that we zero section_mem_map, so the last early_section()
will always report false and the section will not be removed.

Fix this checking whether a section is early or not at function
entry.

Fixes: mmotm ("mm/sparsemem: Support sub-section hotplug")
Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
---
mm/sparse.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index 3267c4001c6d..1e224149aab6 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -738,6 +738,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 };
struct mem_section *ms = __pfn_to_section(pfn);
+ bool section_is_early = early_section(ms);
struct page *memmap = NULL;
unsigned long *subsection_map = ms->usage
? &ms->usage->subsection_map[0] : NULL;
@@ -772,7 +773,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) {
unsigned long section_nr = pfn_to_section_nr(pfn);

- if (!early_section(ms)) {
+ if (!section_is_early) {
kfree(ms->usage);
ms->usage = NULL;
}
@@ -780,7 +781,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
ms->section_mem_map = sparse_encode_mem_map(NULL, section_nr);
}

- if (early_section(ms) && memmap)
+ if (section_is_early && memmap)
free_map_bootmem(memmap);
else
depopulate_section_memmap(pfn, nr_pages, altmap);
--
2.12.3