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From:   David Hildenbrand <david@redhat.com>
To:     linux-kernel@vger.kernel.org
Cc:     linux-mm@kvack.org, David Hildenbrand <david@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@kernel.org>,
        Oscar Salvador <osalvador@suse.de>,
        "Kirill A . Shutemov" <kirill@shutemov.name>
Subject: [PATCH v1 2/2] mm: factor out next_present_section_nr()
Date:   Mon, 13 Jan 2020 15:40:35 +0100
Message-Id: <20200113144035.10848-3-david@redhat.com>
In-Reply-To: <20200113144035.10848-1-david@redhat.com>
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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 i=
n
the caller as it is big enough (>=3D 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)));
 }
=20
+static inline unsigned long next_present_section_nr(unsigned long sectio=
n_nr)
+{
+	while (++section_nr <=3D __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 =3D pfn_to_section_nr(++pfn);
=20
-	section_nr =3D pfn_to_section_nr(++pfn);
 	if (present_section_nr(section_nr))
 		return pfn;
-
-	while (++section_nr <=3D __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 |=3D SECTION_MARKED_PRESENT;
 }
=20
-static inline unsigned long next_present_section_nr(unsigned long sectio=
n_nr)
-{
-	do {
-		section_nr++;
-		if (present_section_nr(section_nr))
-			return section_nr;
-	} while ((section_nr <=3D __highest_present_section_nr));
-
-	return -1;
-}
 #define for_each_present_section_nr(start, section_nr)		\
 	for (section_nr =3D next_present_section_nr(start-1);	\
 	     ((section_nr !=3D -1) &&				\
--=20
2.24.1