[PATCH v2 2/7] mm/sparse.c: introduce new function fill_subsection_map()

Baoquan He
2020-02-20T04:33:46Z

Wrap the codes filling subsection map from section_activate() into
fill_subsection_map(), this makes section_activate() cleaner and
easier to follow.

Signed-off-by: Baoquan He <bhe@redhat.com>
---
mm/sparse.c | 45 ++++++++++++++++++++++++++++++++++-----------
1 file changed, 34 insertions(+), 11 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index b8e52c8fed7f..977b47acd38d 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -790,24 +790,28 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
ms->section_mem_map = (unsigned long)NULL;
}

-static struct page * __meminit section_activate(int nid, unsigned long pfn,
- unsigned long nr_pages, struct vmem_altmap *altmap)
+/**
+ * fill_subsection_map - fill subsection map of a memory region
+ * @pfn - start pfn of the memory range
+ * @nr_pages - number of pfns to add in the region
+ *
+ * This fills the related subsection map inside one section, and only
+ * intended for hotplug.
+ *
+ * Return:
+ * * 0 - On success.
+ * * -EINVAL - Invalid memory region.
+ * * -EEXIST - Subsection map has been set.
+ */
+static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages)
{
- DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
struct mem_section *ms = __pfn_to_section(pfn);
- struct mem_section_usage *usage = NULL;
+ DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
unsigned long *subsection_map;
- struct page *memmap;
int rc = 0;

subsection_mask_set(map, pfn, nr_pages);

- if (!ms->usage) {
- usage = kzalloc(mem_section_usage_size(), GFP_KERNEL);
- if (!usage)
- return ERR_PTR(-ENOMEM);
- ms->usage = usage;
- }
subsection_map = &ms->usage->subsection_map[0];

if (bitmap_empty(map, SUBSECTIONS_PER_SECTION))
@@ -818,6 +822,25 @@ static struct page * __meminit section_activate(int nid, unsigned long pfn,
bitmap_or(subsection_map, map, subsection_map,
SUBSECTIONS_PER_SECTION);

+ return rc;
+}
+
+static struct page * __meminit section_activate(int nid, unsigned long pfn,
+ unsigned long nr_pages, struct vmem_altmap *altmap)
+{
+ struct mem_section *ms = __pfn_to_section(pfn);
+ struct mem_section_usage *usage = NULL;
+ struct page *memmap;
+ int rc = 0;
+
+ if (!ms->usage) {
+ usage = kzalloc(mem_section_usage_size(), GFP_KERNEL);
+ if (!usage)
+ return ERR_PTR(-ENOMEM);
+ ms->usage = usage;
+ }
+
+ rc = fill_subsection_map(pfn, nr_pages);
if (rc) {
if (usage)
ms->usage = NULL;
--
2.17.2