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Subject[PATCH v1 2/2] mm: factor out next_present_section_nr()
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Let's move it to the header and use the shorter variant from
mm/page_alloc.c (the original one will also check
"__highest_present_section_nr + 1", which is not necessary). While at it,
make the section_nr in next_pfn() const.

In next_pfn(), we now return section_nr_to_pfn(-1) instead of -1 once
we exceed __highest_present_section_nr, which doesn't make a difference in
the caller as it is big enough (>= all sane end_pfn).

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
include/linux/mmzone.h | 10 ++++++++++
mm/page_alloc.c | 11 ++---------
mm/sparse.c | 10 ----------
3 files changed, 12 insertions(+), 19 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index c2bc309d1634..462f6873905a 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1379,6 +1379,16 @@ static inline int pfn_present(unsigned long pfn)
return present_section(__nr_to_section(pfn_to_section_nr(pfn)));
}

+static inline unsigned long next_present_section_nr(unsigned long section_nr)
+{
+ while (++section_nr <= __highest_present_section_nr) {
+ if (present_section_nr(section_nr))
+ return section_nr;
+ }
+
+ return -1;
+}
+
/*
* These are _only_ used during initialisation, therefore they
* can use __initdata ... They could have names to indicate
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a92791512077..26e8044e9848 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5852,18 +5852,11 @@ overlap_memmap_init(unsigned long zone, unsigned long *pfn)
/* Skip PFNs that belong to non-present sections */
static inline __meminit unsigned long next_pfn(unsigned long pfn)
{
- unsigned long section_nr;
+ const unsigned long section_nr = pfn_to_section_nr(++pfn);

- section_nr = pfn_to_section_nr(++pfn);
if (present_section_nr(section_nr))
return pfn;
-
- while (++section_nr <= __highest_present_section_nr) {
- if (present_section_nr(section_nr))
- return section_nr_to_pfn(section_nr);
- }
-
- return -1;
+ return section_nr_to_pfn(next_present_section_nr(section_nr));
}
#else
static inline __meminit unsigned long next_pfn(unsigned long pfn)
diff --git a/mm/sparse.c b/mm/sparse.c
index 3822ecbd8a1f..ac4a2bfae514 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -198,16 +198,6 @@ static void section_mark_present(struct mem_section *ms)
ms->section_mem_map |= SECTION_MARKED_PRESENT;
}

-static inline unsigned long next_present_section_nr(unsigned long section_nr)
-{
- do {
- section_nr++;
- if (present_section_nr(section_nr))
- return section_nr;
- } while ((section_nr <= __highest_present_section_nr));
-
- return -1;
-}
#define for_each_present_section_nr(start, section_nr) \
for (section_nr = next_present_section_nr(start-1); \
((section_nr != -1) && \
--
2.24.1
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