+ fs-stable_page_flags-use-bit_ull-for-kpf-flags.patch added to mm-new branch

The patch titled
     Subject: fs: stable_page_flags(): use BIT_ULL() for KPF flags
has been added to the -mm mm-new branch.  Its filename is
     fs-stable_page_flags-use-bit_ull-for-kpf-flags.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fs-stable_page_flags-use-bit_ull-for-kpf-flags.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: Jinjiang Tu <[email protected]>
Subject: fs: stable_page_flags(): use BIT_ULL() for KPF flags
Date: Mon, 20 Jul 2026 11:30:19 +0800

Patch series "cleanup for stable_page_flags()", v2.

This series cleans up stable_page_flags(), see the details in the commit
messages.


This patch (of 3):

The stable_page_flags() function currently sets page flag bits using "1 <<
KPF_xxx" for various KPF_* definitions.  KPF_* may be larger than 32,
which will trigger -Wshift-count-overflow warning.  All KPF_* values
currently used in "1 << KPF_xxx" are smaller than 33, so no warning is
triggered with current code.

Replace all occurrences of "1 << KPF_*" with the BIT_ULL() macro to ensure
all shifts are performed on a 64-bit unsigned type.  This makes the code
robust, and safe for future extension.

No functional change is intended.

Link: https://lore.kernel.org/[email protected]
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Jinjiang Tu <[email protected]>
Acked-by: David Hildenbrand (Arm) <[email protected]>
Acked-by: Zi Yan <[email protected]>
Cc: Chengming Zhou <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Luiz Capitulino <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Miaohe Lin <[email protected]>
Cc: Nanyong Sun <[email protected]>
Cc: Svetly Todorov <[email protected]>
Cc: xu xin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 fs/proc/page.c |   34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

--- a/fs/proc/page.c~fs-stable_page_flags-use-bit_ull-for-kpf-flags
+++ a/fs/proc/page.c
@@ -157,7 +157,7 @@ u64 stable_page_flags(const struct page
 	 * it differentiates a memory hole from a page with no flags
 	 */
 	if (!page)
-		return 1 << KPF_NOPAGE;
+		return BIT_ULL(KPF_NOPAGE);
 
 	snapshot_page(&ps, page);
 	folio = &ps.folio_snapshot;
@@ -170,11 +170,11 @@ u64 stable_page_flags(const struct page
 	 * pseudo flags for the well known (anonymous) memory mapped pages
 	 */
 	if (folio_mapped(folio))
-		u |= 1 << KPF_MMAP;
+		u |= BIT_ULL(KPF_MMAP);
 	if (is_anon) {
-		u |= 1 << KPF_ANON;
+		u |= BIT_ULL(KPF_ANON);
 		if ((mapping & FOLIO_MAPPING_FLAGS) == FOLIO_MAPPING_KSM)
-			u |= 1 << KPF_KSM;
+			u |= BIT_ULL(KPF_KSM);
 	}
 
 	/*
@@ -184,35 +184,35 @@ u64 stable_page_flags(const struct page
 	if (ps.idx == 0)
 		u |= kpf_copy_bit(k, KPF_COMPOUND_HEAD, PG_head);
 	else
-		u |= 1 << KPF_COMPOUND_TAIL;
+		u |= BIT_ULL(KPF_COMPOUND_TAIL);
 	if (folio_test_hugetlb(folio))
-		u |= 1 << KPF_HUGE;
+		u |= BIT_ULL(KPF_HUGE);
 	else if (folio_test_large(folio) &&
 	         folio_test_large_rmappable(folio)) {
 		/* Note: we indicate any THPs here, not just PMD-sized ones */
-		u |= 1 << KPF_THP;
+		u |= BIT_ULL(KPF_THP);
 	} else if (is_huge_zero_pfn(ps.pfn)) {
-		u |= 1 << KPF_ZERO_PAGE;
-		u |= 1 << KPF_THP;
+		u |= BIT_ULL(KPF_ZERO_PAGE);
+		u |= BIT_ULL(KPF_THP);
 	} else if (is_zero_pfn(ps.pfn)) {
-		u |= 1 << KPF_ZERO_PAGE;
+		u |= BIT_ULL(KPF_ZERO_PAGE);
 	}
 
 	if (ps.flags & PAGE_SNAPSHOT_PG_BUDDY)
-		u |= 1 << KPF_BUDDY;
+		u |= BIT_ULL(KPF_BUDDY);
 
 	if (folio_test_offline(folio))
-		u |= 1 << KPF_OFFLINE;
+		u |= BIT_ULL(KPF_OFFLINE);
 	if (folio_test_pgtable(folio))
-		u |= 1 << KPF_PGTABLE;
+		u |= BIT_ULL(KPF_PGTABLE);
 	if (folio_test_slab(folio))
-		u |= 1 << KPF_SLAB;
+		u |= BIT_ULL(KPF_SLAB);
 
 #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
 	u |= kpf_copy_bit(k, KPF_IDLE,          PG_idle);
 #else
 	if (ps.flags & PAGE_SNAPSHOT_PG_IDLE)
-		u |= 1 << KPF_IDLE;
+		u |= BIT_ULL(KPF_IDLE);
 #endif
 
 	u |= kpf_copy_bit(k, KPF_LOCKED,	PG_locked);
@@ -227,14 +227,14 @@ u64 stable_page_flags(const struct page
 
 #define SWAPCACHE ((1 << PG_swapbacked) | (1 << PG_swapcache))
 	if ((k & SWAPCACHE) == SWAPCACHE)
-		u |= 1 << KPF_SWAPCACHE;
+		u |= BIT_ULL(KPF_SWAPCACHE);
 	u |= kpf_copy_bit(k, KPF_SWAPBACKED,	PG_swapbacked);
 
 	u |= kpf_copy_bit(k, KPF_UNEVICTABLE,	PG_unevictable);
 	u |= kpf_copy_bit(k, KPF_MLOCKED,	PG_mlocked);
 
 #ifdef CONFIG_MEMORY_FAILURE
-	if (u & (1 << KPF_HUGE))
+	if (u & BIT_ULL(KPF_HUGE))
 		u |= kpf_copy_bit(k, KPF_HWPOISON,	PG_hwpoison);
 	else
 		u |= kpf_copy_bit(ps.page_snapshot.flags.f, KPF_HWPOISON, PG_hwpoison);
_

Patches currently in -mm which might be from [email protected] are

fs-stable_page_flags-use-bit_ull-for-kpf-flags.patch
fs-stable_page_flags-use-folio_test_-helpers.patch
fs-stable_page_flags-simplify-kpf_idle-handling.patch