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Subject[PATCH v3 3/7] mm/sparse.c: introduce a new function clear_subsection_map()
Date
Factor out the code which clear subsection map of one memory region from
section_deactivate() into clear_subsection_map().

Signed-off-by: Baoquan He <bhe@redhat.com>
---
mm/sparse.c | 31 ++++++++++++++++++++++++-------
1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index e37c0abcdc89..d9dcd58d5c1d 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -726,15 +726,11 @@ static void free_map_bootmem(struct page *memmap)
}
#endif /* CONFIG_SPARSEMEM_VMEMMAP */

-static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
- struct vmem_altmap *altmap)
+static int clear_subsection_map(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;
- bool empty = false;
unsigned long *subsection_map = ms->usage
? &ms->usage->subsection_map[0] : NULL;

@@ -745,8 +741,31 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION),
"section already deactivated (%#lx + %ld)\n",
pfn, nr_pages))
+ return -EINVAL;
+
+ bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION);
+
+ return 0;
+}
+
+static bool is_subsection_map_empty(struct mem_section *ms)
+{
+ return bitmap_empty(&ms->usage->subsection_map[0],
+ SUBSECTIONS_PER_SECTION);
+}
+
+static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
+ struct vmem_altmap *altmap)
+{
+ struct mem_section *ms = __pfn_to_section(pfn);
+ bool section_is_early = early_section(ms);
+ struct page *memmap = NULL;
+ bool empty = false;
+
+ if (clear_subsection_map(pfn, nr_pages))
return;

+ empty = is_subsection_map_empty(ms);
/*
* There are 3 cases to handle across two configurations
* (SPARSEMEM_VMEMMAP={y,n}):
@@ -764,8 +783,6 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
*
* For 2/ and 3/ the SPARSEMEM_VMEMMAP={y,n} cases are unified
*/
- bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION);
- empty = bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION);
if (empty) {
unsigned long section_nr = pfn_to_section_nr(pfn);

--
2.17.2
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