[to-be-updated] mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix.patch removed from -mm tree

[to-be-updated] mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix
has been removed from the -mm tree.  Its filename was
     mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix.patch

This patch was dropped because an updated version will be issued

------------------------------------------------------
From: Andrew Morton <akpm@linux-foundation.org>
Subject: mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix
Date: Wed Sep  9 03:33:07 PM PDT 2026

hack around build error

https://lore.kernel.org/202609100517.0DrzxrW4-lkp@intel.com
Cc: David Hildenbrand <david@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/mmzone.h |    4 ++++
 1 file changed, 4 insertions(+)

--- a/include/linux/mmzone.h~mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix
+++ a/include/linux/mmzone.h
@@ -1687,16 +1687,20 @@ static inline bool zone_is_zone_device(c
 	return zone_idx(zone) == ZONE_DEVICE;
 }
 
+#ifdef CONFIG_NUMA
 static inline struct zone *device_zone(int nid)
 {
 	return &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
 }
+#endif
 #else
 static inline bool zone_is_zone_device(const struct zone *zone)
 {
 	return false;
 }
+#endif
 
+#if !defined(CONFIG_ZONE_DEVICE) && !defined(CONFIG_NUMA)
 static inline struct zone *device_zone(int nid)
 {
 	return NULL;
_

Patches currently in -mm which might be from akpm@linux-foundation.org are

mm-memory_hotplug-factor-out-node_is_memoryless-fix.patch
drivers-media-v4l2-core-v4l2-vp9c-reduce-inlining.patch

[to-be-updated] mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix
has been removed from the -mm tree.  Its filename was
     mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix.patch

This patch was dropped because an updated version will be issued

------------------------------------------------------
From: Muchun Song <muchun.song@linux.dev>
Subject: mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix
Date: Thu, 10 Sep 2026 10:43:41 +0800

device_zone() uses NODE_DATA() before it is defined when CONFIG_NUMA is
disabled.  This causes non-NUMA builds with CONFIG_ZONE_DEVICE=y to fail.

Move device_zone() after the definition of NODE_DATA() so it is available
in non-NUMA builds.

Link: https://lore.kernel.org/AA5FC896-AC1B-4112-BA14-E1F8865358BF@linux.dev
Signed-off-by: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/mmzone.h |   20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

--- a/include/linux/mmzone.h~mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix
+++ a/include/linux/mmzone.h
@@ -1686,21 +1686,11 @@ static inline bool zone_is_zone_device(c
 {
 	return zone_idx(zone) == ZONE_DEVICE;
 }
-
-static inline struct zone *device_zone(int nid)
-{
-	return &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
-}
 #else
 static inline bool zone_is_zone_device(const struct zone *zone)
 {
 	return false;
 }
-
-static inline struct zone *device_zone(int nid)
-{
-	return NULL;
-}
 #endif
 
 /*
@@ -2159,11 +2149,21 @@ static inline int online_device_section(
 
 	return section && ((section->section_mem_map & flags) == flags);
 }
+
+static inline struct zone *device_zone(int nid)
+{
+	return &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
+}
 #else
 static inline int online_device_section(const struct mem_section *section)
 {
 	return 0;
 }
+
+static inline struct zone *device_zone(int nid)
+{
+	return NULL;
+}
 #endif
 
 static inline int online_section_nr(unsigned long nr)
_

Patches currently in -mm which might be from muchun.song@linux.dev are

[to-be-updated] mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix
has been removed from the -mm tree.  Its filename was
     mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix.patch

This patch was dropped because an updated version will be issued

------------------------------------------------------
From: Muchun Song <muchun.song@linux.dev>
Subject: mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix
Date: Mon, 28 Sep 2026 12:41:48 +0800

Each PTE mapping the shared device DAX tail page takes a page reference.
A sufficiently large range could therefore cycle the reference count back
to zero if population were allowed to continue after it became
non-positive.

Use try_get_page() so further mappings fail once the reference count is no
longer positive. The section population error path tears down mappings
created for the failed section, while the warning makes this currently
impractical limit visible.

Link: https://lore.kernel.org/20260928044148.3300333-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <chleroy@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Lance Yang <lance.yang@linux.dev>
---

 mm/sparse-vmemmap.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/mm/sparse-vmemmap.c~mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix
+++ a/mm/sparse-vmemmap.c
@@ -286,14 +286,18 @@ static pte_t * __meminit vmemmap_pte_pop
 			/*
 			 * When a PTE/PMD entry is freed from the init_mm
 			 * there's a free_pages() call to this page allocated
-			 * above. Thus this get_page() is paired with the
+			 * above. Thus this try_get_page() is paired with the
 			 * put_page_testzero() on the freeing path.
 			 * This can only called by certain ZONE_DEVICE path,
 			 * and through vmemmap_populate_compound_pages() when
 			 * slab is available.
+			 *
+			 * Use try_get_page() to prevent the shared page refcount
+			 * from overflowing.
 			 */
-			if (flags & VMEMMAP_POPULATE_DAX)
-				get_page(pfn_to_page(ptpfn));
+			if ((flags & VMEMMAP_POPULATE_DAX) &&
+			    !try_get_page(pfn_to_page(ptpfn)))
+				return NULL;
 		}
 		entry = pfn_pte(ptpfn, PAGE_KERNEL);
 		set_pte_at(&init_mm, addr, pte, entry);
_

Patches currently in -mm which might be from muchun.song@linux.dev are

mm-sparse-vmemmap-move-vmemmap-optimization-helpers-to-a-public-header.patch
powerpc-mm-switch-device-dax-to-shared-tail-vmemmap-pages.patch
mm-sparse-vmemmap-drop-the-extra-tail-page-from-device-dax-reservation.patch
mm-sparse-vmemmap-drop-unused-section_nr_vmemmap_pages-arguments.patch
documentation-mm-update-dax-vmemmap-deduplication-docs.patch
mm-sparse-vmemmap-drop-vmemmap_populate_dax.patch
mm-sparse-vmemmap-support-device-dax-in-common-vmemmap-path.patch
mm-sparse-vmemmap-drop-device-dax-specific-population-path.patch
mm-sparse-vmemmap-remove-the-unused-ptpfn-argument.patch
mm-sparse-vmemmap-open-code-vmemmap_populate_address.patch
mm-mm_init-add-zone-mismatch-warning-during-page-init.patch