[PATCH 09/12] mm/sparse: remove SECTION_MARKED_PRESENT

["David Hildenbrand (Arm)" <david@kernel.org>]

All present section iterators run before memory hotplug added any
further memory sections, Therefore, we can simply use the SECTION_IS_EARLY
flag by setting that flag earlier in sparse_prepare_early_sections().

Get rid of SECTION_MARKED_PRESENT entirely and rename
for_each_present_section_nr() to for_each_early_section_nr().

Also update the gdb script to use the updated value for
SECTION_IS_EARLY.

No functional change intended.

Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
---
 drivers/base/memory.c   |  2 +-
 include/linux/mmzone.h  | 27 ++++++++++-----------------
 mm/sparse-vmemmap.c     |  1 -
 mm/sparse.c             | 17 ++++++++---------
 mm/sparse.h             |  6 ------
 scripts/gdb/linux/mm.py |  2 +-
 6 files changed, 20 insertions(+), 35 deletions(-)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 5eead3346f1e3..b0338de2f1d82 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -972,7 +972,7 @@ void __init memory_dev_init(void)
 	 * block so that it can be covered.
 	 */
 	block_id = ULONG_MAX;
-	for_each_present_section_nr(0, nr) {
+	for_each_early_section_nr(0, nr) {
 		if (block_id != ULONG_MAX && memory_block_id(nr) == block_id)
 			continue;
 
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index e0fac344f6ac2..62cff59dd80c4 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -2084,7 +2084,6 @@ static inline struct mem_section *__nr_to_section(unsigned long nr)
  * accommodate SECTION_MAP_LAST_BIT. We use BUILD_BUG_ON() to ensure this.
  */
 enum {
-	SECTION_MARKED_PRESENT_BIT,
 	SECTION_HAS_MEM_MAP_BIT,
 	SECTION_IS_ONLINE_BIT,
 	SECTION_IS_EARLY_BIT,
@@ -2094,7 +2093,6 @@ enum {
 	SECTION_MAP_LAST_BIT,
 };
 
-#define SECTION_MARKED_PRESENT		BIT(SECTION_MARKED_PRESENT_BIT)
 #define SECTION_HAS_MEM_MAP		BIT(SECTION_HAS_MEM_MAP_BIT)
 #define SECTION_IS_ONLINE		BIT(SECTION_IS_ONLINE_BIT)
 #define SECTION_IS_EARLY		BIT(SECTION_IS_EARLY_BIT)
@@ -2111,16 +2109,6 @@ static inline struct page *__section_mem_map_addr(struct mem_section *section)
 	return (struct page *)map;
 }
 
-static inline int present_section(const struct mem_section *section)
-{
-	return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
-}
-
-static inline int present_section_nr(unsigned long nr)
-{
-	return present_section(__nr_to_section(nr));
-}
-
 static inline int valid_section(const struct mem_section *section)
 {
 	return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
@@ -2136,6 +2124,11 @@ static inline int valid_section_nr(unsigned long nr)
 	return valid_section(__nr_to_section(nr));
 }
 
+static inline int early_section_nr(unsigned long nr)
+{
+	return early_section(__nr_to_section(nr));
+}
+
 static inline int online_section(const struct mem_section *section)
 {
 	return (section && (section->section_mem_map & SECTION_IS_ONLINE));
@@ -2315,20 +2308,20 @@ static inline unsigned long next_valid_pfn(unsigned long pfn, unsigned long end_
 
 #endif
 
-static inline unsigned long next_present_section_nr(unsigned long section_nr)
+static inline unsigned long next_early_section_nr(unsigned long section_nr)
 {
 	while (++section_nr <= __highest_used_section_nr) {
-		if (present_section_nr(section_nr))
+		if (early_section_nr(section_nr))
 			return section_nr;
 	}
 
 	return -1;
 }
 
-#define for_each_present_section_nr(start, section_nr)		\
-	for (section_nr = next_present_section_nr(start - 1);	\
+#define for_each_early_section_nr(start, section_nr)		\
+	for (section_nr = next_early_section_nr(start - 1);	\
 	     section_nr != -1;					\
-	     section_nr = next_present_section_nr(section_nr))
+	     section_nr = next_early_section_nr(section_nr))
 
 /*
  * These are _only_ used during initialisation, therefore they
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index e62e6aa07f126..5aba058df6b67 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -890,7 +890,6 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn,
 	page_init_poison(memmap, sizeof(struct page) * nr_pages);
 
 	ms = __nr_to_section(section_nr);
-	__section_mark_present(ms, section_nr);
 
 	/* Align memmap to section boundary in the subsection case */
 	if (section_nr_to_pfn(section_nr) != start_pfn)
diff --git a/mm/sparse.c b/mm/sparse.c
index 2d0f2db34f4cf..344acaaed94db 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -170,13 +170,14 @@ static void __init mminit_validate_memmodel_limits(unsigned long *start_pfn,
  */
 unsigned long __highest_used_section_nr;
 
-static inline unsigned long first_present_section_nr(void)
+static inline unsigned long first_early_section_nr(void)
 {
-	return next_present_section_nr(-1);
+	return next_early_section_nr(-1);
 }
 
 void __init sparse_sections_init(void)
 {
+	const unsigned long flags = SECTION_IS_EARLY | SECTION_IS_ONLINE;
 	unsigned long pfn, start_pfn, end_pfn, section_nr;
 	int i, nid;
 
@@ -196,9 +197,7 @@ void __init sparse_sections_init(void)
 				continue;
 
 			set_section_nid(section_nr, nid);
-			ms->section_mem_map = sparse_encode_early_nid(nid) |
-							SECTION_IS_ONLINE;
-			__section_mark_present(ms, section_nr);
+			ms->section_mem_map = sparse_encode_early_nid(nid) | flags;
 		}
 	}
 	__highest_used_section_nr = section_nr;
@@ -231,7 +230,7 @@ static void __init sparse_metadata_init_nid(int nid,
 	if (!usage)
 		panic("Failed to allocate usemap for node %d\n", nid);
 
-	for_each_present_section_nr(start_section_nr, section_nr) {
+	for_each_early_section_nr(start_section_nr, section_nr) {
 		unsigned long pfn = section_nr_to_pfn(section_nr);
 		struct page *mem_map;
 
@@ -246,18 +245,18 @@ static void __init sparse_metadata_init_nid(int nid,
 		memmap_boot_pages_add(section_nr_vmemmap_pages(pfn, PAGES_PER_SECTION,
 							       NULL, NULL));
 		sparse_init_one_section(__nr_to_section(section_nr), section_nr,
-					mem_map, usage, SECTION_IS_EARLY);
+					mem_map, usage, 0);
 		usage = (void *)usage + mem_section_usage_size();
 	}
 }
 
 static void __init sparse_metadata_init(void)
 {
-	unsigned long start_section_nr = first_present_section_nr();
+	unsigned long start_section_nr = first_early_section_nr();
 	int nid_begin = sparse_early_nid(__nr_to_section(start_section_nr));
 	unsigned long section_nr, nr_sections = 1;
 
-	for_each_present_section_nr(start_section_nr + 1, section_nr) {
+	for_each_early_section_nr(start_section_nr + 1, section_nr) {
 		const int nid = sparse_early_nid(__nr_to_section(section_nr));
 
 		if (nid == nid_begin) {
diff --git a/mm/sparse.h b/mm/sparse.h
index a3af4967fd5c5..03351f2467e34 100644
--- a/mm/sparse.h
+++ b/mm/sparse.h
@@ -114,12 +114,6 @@ static inline void sparse_init_one_section(struct mem_section *ms,
 	ms->usage = usage;
 }
 
-static inline void __section_mark_present(struct mem_section *ms,
-		unsigned long section_nr)
-{
-	ms->section_mem_map |= SECTION_MARKED_PRESENT;
-}
-
 static inline size_t mem_section_usage_size(void)
 {
 	return struct_size_t(struct mem_section_usage, pageblock_flags,
diff --git a/scripts/gdb/linux/mm.py b/scripts/gdb/linux/mm.py
index 193a88d763abf..73d637d28c8e6 100644
--- a/scripts/gdb/linux/mm.py
+++ b/scripts/gdb/linux/mm.py
@@ -76,7 +76,7 @@ class x86_page_ops():
             self.SECTION_IS_EARLY = 1 << int(gdb.parse_and_eval('SECTION_IS_EARLY_BIT'))
         except:
             self.SECTION_HAS_MEM_MAP = 1 << 0
-            self.SECTION_IS_EARLY = 1 << 3
+            self.SECTION_IS_EARLY = 1 << 2
 
         self.SUBSECTION_SHIFT = 21
         self.PAGES_PER_SUBSECTION = 1 << (self.SUBSECTION_SHIFT - self.PAGE_SHIFT)

-- 
2.43.0