[PATCH v2 0/1] mm: pgtable: fix pte_swp_exclusive

[PATCH v2 0/1] mm: pgtable: fix pte_swp_exclusive

[Magnus Lindholm]

The first version of this patch intended to fix issues with swap memory on
alpha, when swapoff fails to writeback exclusive swap pages and gets stuck
in an infinite loop trying to do so. This problem appeared after commit
a172d5128706028ac07b8db709728379ecc72f6e and as far as I know only
affected the alpha architecure.

Changes in v2:
As suggested by Al Viro, rather than doing a bit-shift alpha-only fix this
version of the patch makes pte_swp_exclusive return bool instead of int.
As Al pointed out, this will also better reflect how pte_swp_exclusive
is actually used in the code.

Best regards
Magnus Lindholm linmag7@gmail.com

 arch/alpha/include/asm/pgtable.h             | 2 +-
 arch/arc/include/asm/pgtable-bits-arcv2.h    | 2 +-
 arch/arm/include/asm/pgtable.h               | 2 +-
 arch/arm64/include/asm/pgtable.h             | 2 +-
 arch/csky/include/asm/pgtable.h              | 2 +-
 arch/hexagon/include/asm/pgtable.h           | 2 +-
 arch/loongarch/include/asm/pgtable.h         | 2 +-
 arch/m68k/include/asm/mcf_pgtable.h          | 2 +-
 arch/m68k/include/asm/motorola_pgtable.h     | 2 +-
 arch/m68k/include/asm/sun3_pgtable.h         | 2 +-
 arch/microblaze/include/asm/pgtable.h        | 2 +-
 arch/mips/include/asm/pgtable.h              | 4 ++--
 arch/nios2/include/asm/pgtable.h             | 2 +-
 arch/openrisc/include/asm/pgtable.h          | 2 +-
 arch/parisc/include/asm/pgtable.h            | 2 +-
 arch/powerpc/include/asm/book3s/32/pgtable.h | 2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +-
 arch/powerpc/include/asm/nohash/pgtable.h    | 2 +-
 arch/riscv/include/asm/pgtable.h             | 2 +-
 arch/s390/include/asm/pgtable.h              | 2 +-
 arch/sh/include/asm/pgtable_32.h             | 2 +-
 arch/sparc/include/asm/pgtable_32.h          | 2 +-
 arch/sparc/include/asm/pgtable_64.h          | 2 +-
 arch/um/include/asm/pgtable.h                | 2 +-
 arch/x86/include/asm/pgtable.h               | 2 +-
 arch/xtensa/include/asm/pgtable.h            | 2 +-
 26 files changed, 27 insertions(+), 27 deletions(-)

[PATCH v2 1/1] mm: pgtable: fix pte_swp_exclusive

[Magnus Lindholm]

Make pte_swp_exclusive return bool instead of int. This will better reflect
how pte_swp_exclusive is actually used in the code. This fixes swap/swapoff
problems on Alpha due pte_swp_exclusive not returning correct values when
_PAGE_SWP_EXCLUSIVE bit resides in upper 32-bits of PTE (like on alpha).

Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
---
 arch/alpha/include/asm/pgtable.h             | 2 +-
 arch/arc/include/asm/pgtable-bits-arcv2.h    | 2 +-
 arch/arm/include/asm/pgtable.h               | 2 +-
 arch/arm64/include/asm/pgtable.h             | 2 +-
 arch/csky/include/asm/pgtable.h              | 2 +-
 arch/hexagon/include/asm/pgtable.h           | 2 +-
 arch/loongarch/include/asm/pgtable.h         | 2 +-
 arch/m68k/include/asm/mcf_pgtable.h          | 2 +-
 arch/m68k/include/asm/motorola_pgtable.h     | 2 +-
 arch/m68k/include/asm/sun3_pgtable.h         | 2 +-
 arch/microblaze/include/asm/pgtable.h        | 2 +-
 arch/mips/include/asm/pgtable.h              | 4 ++--
 arch/nios2/include/asm/pgtable.h             | 2 +-
 arch/openrisc/include/asm/pgtable.h          | 2 +-
 arch/parisc/include/asm/pgtable.h            | 2 +-
 arch/powerpc/include/asm/book3s/32/pgtable.h | 2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +-
 arch/powerpc/include/asm/nohash/pgtable.h    | 2 +-
 arch/riscv/include/asm/pgtable.h             | 2 +-
 arch/s390/include/asm/pgtable.h              | 2 +-
 arch/sh/include/asm/pgtable_32.h             | 2 +-
 arch/sparc/include/asm/pgtable_32.h          | 2 +-
 arch/sparc/include/asm/pgtable_64.h          | 2 +-
 arch/um/include/asm/pgtable.h                | 2 +-
 arch/x86/include/asm/pgtable.h               | 2 +-
 arch/xtensa/include/asm/pgtable.h            | 2 +-
 26 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pgtable.h
index 02e8817a8921..b0870de4b5b8 100644
--- a/arch/alpha/include/asm/pgtable.h
+++ b/arch/alpha/include/asm/pgtable.h
@@ -334,7 +334,7 @@ extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/arc/include/asm/pgtable-bits-arcv2.h b/arch/arc/include/asm/pgtable-bits-arcv2.h
index 8ebec1b21d24..3084c53f402d 100644
--- a/arch/arc/include/asm/pgtable-bits-arcv2.h
+++ b/arch/arc/include/asm/pgtable-bits-arcv2.h
@@ -130,7 +130,7 @@ void update_mmu_cache_range(struct vm_fault *vmf, struct vm_area_struct *vma,
 #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index be91e376df79..aa4f3f71789c 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -303,7 +303,7 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(swp)	__pte((swp).val)
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_isset(pte, L_PTE_SWP_EXCLUSIVE);
 }
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 0b2a2ad1b9e8..b48b70d8d12d 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -496,7 +496,7 @@ static inline pte_t pte_swp_mkexclusive(pte_t pte)
 	return set_pte_bit(pte, __pgprot(PTE_SWP_EXCLUSIVE));
 }
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & PTE_SWP_EXCLUSIVE;
 }
diff --git a/arch/csky/include/asm/pgtable.h b/arch/csky/include/asm/pgtable.h
index a397e1718ab6..e68722eb33d9 100644
--- a/arch/csky/include/asm/pgtable.h
+++ b/arch/csky/include/asm/pgtable.h
@@ -200,7 +200,7 @@ static inline pte_t pte_mkyoung(pte_t pte)
 	return pte;
 }
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/hexagon/include/asm/pgtable.h b/arch/hexagon/include/asm/pgtable.h
index 8c5b7a1c3d90..fa007eb9aad3 100644
--- a/arch/hexagon/include/asm/pgtable.h
+++ b/arch/hexagon/include/asm/pgtable.h
@@ -390,7 +390,7 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
 		(((type & 0x1f) << 1) | \
 		 ((offset & 0x3ffff8) << 10) | ((offset & 0x7) << 7)) })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
index da346733a1da..bac946693d87 100644
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h
@@ -302,7 +302,7 @@ static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
 #define __pmd_to_swp_entry(pmd) ((swp_entry_t) { pmd_val(pmd) })
 #define __swp_entry_to_pmd(x)	((pmd_t) { (x).val | _PAGE_HUGE })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/m68k/include/asm/mcf_pgtable.h b/arch/m68k/include/asm/mcf_pgtable.h
index 48f87a8a8832..7e9748b29c44 100644
--- a/arch/m68k/include/asm/mcf_pgtable.h
+++ b/arch/m68k/include/asm/mcf_pgtable.h
@@ -274,7 +274,7 @@ extern pgd_t kernel_pg_dir[PTRS_PER_PGD];
 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)	(__pte((x).val))
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/m68k/include/asm/motorola_pgtable.h b/arch/m68k/include/asm/motorola_pgtable.h
index 9866c7acdabe..26da9b985c5f 100644
--- a/arch/m68k/include/asm/motorola_pgtable.h
+++ b/arch/m68k/include/asm/motorola_pgtable.h
@@ -191,7 +191,7 @@ extern pgd_t kernel_pg_dir[128];
 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/m68k/include/asm/sun3_pgtable.h b/arch/m68k/include/asm/sun3_pgtable.h
index 30081aee8164..ac0793f57f31 100644
--- a/arch/m68k/include/asm/sun3_pgtable.h
+++ b/arch/m68k/include/asm/sun3_pgtable.h
@@ -175,7 +175,7 @@ extern pgd_t kernel_pg_dir[PTRS_PER_PGD];
 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/microblaze/include/asm/pgtable.h b/arch/microblaze/include/asm/pgtable.h
index e4ea2ec3642f..b281c2bbd6c0 100644
--- a/arch/microblaze/include/asm/pgtable.h
+++ b/arch/microblaze/include/asm/pgtable.h
@@ -406,7 +406,7 @@ extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) >> 2 })
 #define __swp_entry_to_pte(x)	((pte_t) { (x).val << 2 })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index c29a551eb0ca..c19da4ab7552 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -540,7 +540,7 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 #endif
 
 #if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte.pte_low & _PAGE_SWP_EXCLUSIVE;
 }
@@ -557,7 +557,7 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
 	return pte;
 }
 #else
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h
index eab87c6beacb..64ce06bae8ac 100644
--- a/arch/nios2/include/asm/pgtable.h
+++ b/arch/nios2/include/asm/pgtable.h
@@ -265,7 +265,7 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
 #define __swp_entry_to_pte(swp)	((pte_t) { (swp).val })
 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/openrisc/include/asm/pgtable.h b/arch/openrisc/include/asm/pgtable.h
index 60c6ce7ff2dc..34cad9177a48 100644
--- a/arch/openrisc/include/asm/pgtable.h
+++ b/arch/openrisc/include/asm/pgtable.h
@@ -413,7 +413,7 @@ static inline void update_mmu_cache_range(struct vm_fault *vmf,
 #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index babf65751e81..dfeba45b6d6f 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -431,7 +431,7 @@ static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
 #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 42c3af90d1f0..92d21c6faf1e 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -365,7 +365,7 @@ static inline void __ptep_set_access_flags(struct vm_area_struct *vma,
 #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) >> 3 })
 #define __swp_entry_to_pte(x)		((pte_t) { (x).val << 3 })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 6d98e6f08d4d..dbf772bef20d 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -693,7 +693,7 @@ static inline pte_t pte_swp_mkexclusive(pte_t pte)
 	return __pte_raw(pte_raw(pte) | cpu_to_be64(_PAGE_SWP_EXCLUSIVE));
 }
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return !!(pte_raw(pte) & cpu_to_be64(_PAGE_SWP_EXCLUSIVE));
 }
diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
index 8d1f0b7062eb..7d6b9e5b286e 100644
--- a/arch/powerpc/include/asm/nohash/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/pgtable.h
@@ -286,7 +286,7 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 	return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
 }
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 050fdc49b5ad..433c78c44e02 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -880,7 +880,7 @@ extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 3ca5af4cfe43..cb86dbf7126a 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -913,7 +913,7 @@ static inline int pmd_protnone(pmd_t pmd)
 }
 #endif
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/sh/include/asm/pgtable_32.h b/arch/sh/include/asm/pgtable_32.h
index f939f1215232..5f221f3269e3 100644
--- a/arch/sh/include/asm/pgtable_32.h
+++ b/arch/sh/include/asm/pgtable_32.h
@@ -478,7 +478,7 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
 /* In both cases, we borrow bit 6 to store the exclusive marker in swap PTEs. */
 #define _PAGE_SWP_EXCLUSIVE	_PAGE_USER
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte.pte_low & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
index 62bcafe38b1f..0362f8357371 100644
--- a/arch/sparc/include/asm/pgtable_32.h
+++ b/arch/sparc/include/asm/pgtable_32.h
@@ -353,7 +353,7 @@ static inline swp_entry_t __swp_entry(unsigned long type, unsigned long offset)
 #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & SRMMU_SWP_EXCLUSIVE;
 }
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 2b7f358762c1..65e53491fe07 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -1027,7 +1027,7 @@ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h
index 5601ca98e8a6..c32309614a15 100644
--- a/arch/um/include/asm/pgtable.h
+++ b/arch/um/include/asm/pgtable.h
@@ -316,7 +316,7 @@ extern pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr);
 	((swp_entry_t) { pte_val(pte_mkuptodate(pte)) })
 #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_get_bits(pte, _PAGE_SWP_EXCLUSIVE);
 }
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 593f10aabd45..4c7ce40023d3 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1586,7 +1586,7 @@ static inline pte_t pte_swp_mkexclusive(pte_t pte)
 	return pte_set_flags(pte, _PAGE_SWP_EXCLUSIVE);
 }
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_flags(pte) & _PAGE_SWP_EXCLUSIVE;
 }
diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
index 1647a7cc3fbf..6da0aa0604f1 100644
--- a/arch/xtensa/include/asm/pgtable.h
+++ b/arch/xtensa/include/asm/pgtable.h
@@ -355,7 +355,7 @@ ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
 
-static inline int pte_swp_exclusive(pte_t pte)
+static inline bool pte_swp_exclusive(pte_t pte)
 {
 	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
 }
-- 
2.48.1

Re: [PATCH v2 1/1] mm: pgtable: fix pte_swp_exclusive

[Sam James]

Lovely cleanup and a great suggestion from Al.

Reviewed-by: Sam James <sam@gentoo.org>

I'd suggest adding a:
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>

thanks,
sam

Re: [PATCH v2 1/1] mm: pgtable: fix pte_swp_exclusive

[Sam James]

Sam James <sam@gentoo.org> writes:

> Lovely cleanup and a great suggestion from Al.
>
> Reviewed-by: Sam James <sam@gentoo.org>
>
> I'd suggest adding a:
> Suggested-by: Al Viro <viro@zeniv.linux.org.uk>

Al, were you planning on taking this through your tree?

>
> thanks,
> sam

Re: [PATCH v2 1/1] mm: pgtable: fix pte_swp_exclusive

[John Paul Adrian Glaubitz]

Hi Magnus,

On Tue, 2025-02-18 at 18:55 +0100, Magnus Lindholm wrote:
> Make pte_swp_exclusive return bool instead of int. This will better reflect
> how pte_swp_exclusive is actually used in the code. This fixes swap/swapoff
> problems on Alpha due pte_swp_exclusive not returning correct values when
> _PAGE_SWP_EXCLUSIVE bit resides in upper 32-bits of PTE (like on alpha).

Minor nitpick:

"when _PAGE_SWP_EXCLUSIVE" => "when the _PAGE_SWP_EXCLUSIVE"

> 
> Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
> ---
>  arch/alpha/include/asm/pgtable.h             | 2 +-
>  arch/arc/include/asm/pgtable-bits-arcv2.h    | 2 +-
>  arch/arm/include/asm/pgtable.h               | 2 +-
>  arch/arm64/include/asm/pgtable.h             | 2 +-
>  arch/csky/include/asm/pgtable.h              | 2 +-
>  arch/hexagon/include/asm/pgtable.h           | 2 +-
>  arch/loongarch/include/asm/pgtable.h         | 2 +-
>  arch/m68k/include/asm/mcf_pgtable.h          | 2 +-
>  arch/m68k/include/asm/motorola_pgtable.h     | 2 +-
>  arch/m68k/include/asm/sun3_pgtable.h         | 2 +-
>  arch/microblaze/include/asm/pgtable.h        | 2 +-
>  arch/mips/include/asm/pgtable.h              | 4 ++--
>  arch/nios2/include/asm/pgtable.h             | 2 +-
>  arch/openrisc/include/asm/pgtable.h          | 2 +-
>  arch/parisc/include/asm/pgtable.h            | 2 +-
>  arch/powerpc/include/asm/book3s/32/pgtable.h | 2 +-
>  arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +-
>  arch/powerpc/include/asm/nohash/pgtable.h    | 2 +-
>  arch/riscv/include/asm/pgtable.h             | 2 +-
>  arch/s390/include/asm/pgtable.h              | 2 +-
>  arch/sh/include/asm/pgtable_32.h             | 2 +-
>  arch/sparc/include/asm/pgtable_32.h          | 2 +-
>  arch/sparc/include/asm/pgtable_64.h          | 2 +-
>  arch/um/include/asm/pgtable.h                | 2 +-
>  arch/x86/include/asm/pgtable.h               | 2 +-
>  arch/xtensa/include/asm/pgtable.h            | 2 +-
>  26 files changed, 27 insertions(+), 27 deletions(-)
> 
> diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pgtable.h
> index 02e8817a8921..b0870de4b5b8 100644
> --- a/arch/alpha/include/asm/pgtable.h
> +++ b/arch/alpha/include/asm/pgtable.h
> @@ -334,7 +334,7 @@ extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
>  #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
>  #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/arc/include/asm/pgtable-bits-arcv2.h b/arch/arc/include/asm/pgtable-bits-arcv2.h
> index 8ebec1b21d24..3084c53f402d 100644
> --- a/arch/arc/include/asm/pgtable-bits-arcv2.h
> +++ b/arch/arc/include/asm/pgtable-bits-arcv2.h
> @@ -130,7 +130,7 @@ void update_mmu_cache_range(struct vm_fault *vmf, struct vm_area_struct *vma,
>  #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
>  #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
> index be91e376df79..aa4f3f71789c 100644
> --- a/arch/arm/include/asm/pgtable.h
> +++ b/arch/arm/include/asm/pgtable.h
> @@ -303,7 +303,7 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
>  #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
>  #define __swp_entry_to_pte(swp)	__pte((swp).val)
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_isset(pte, L_PTE_SWP_EXCLUSIVE);
>  }
> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> index 0b2a2ad1b9e8..b48b70d8d12d 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -496,7 +496,7 @@ static inline pte_t pte_swp_mkexclusive(pte_t pte)
>  	return set_pte_bit(pte, __pgprot(PTE_SWP_EXCLUSIVE));
>  }
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & PTE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/csky/include/asm/pgtable.h b/arch/csky/include/asm/pgtable.h
> index a397e1718ab6..e68722eb33d9 100644
> --- a/arch/csky/include/asm/pgtable.h
> +++ b/arch/csky/include/asm/pgtable.h
> @@ -200,7 +200,7 @@ static inline pte_t pte_mkyoung(pte_t pte)
>  	return pte;
>  }
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/hexagon/include/asm/pgtable.h b/arch/hexagon/include/asm/pgtable.h
> index 8c5b7a1c3d90..fa007eb9aad3 100644
> --- a/arch/hexagon/include/asm/pgtable.h
> +++ b/arch/hexagon/include/asm/pgtable.h
> @@ -390,7 +390,7 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
>  		(((type & 0x1f) << 1) | \
>  		 ((offset & 0x3ffff8) << 10) | ((offset & 0x7) << 7)) })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
> index da346733a1da..bac946693d87 100644
> --- a/arch/loongarch/include/asm/pgtable.h
> +++ b/arch/loongarch/include/asm/pgtable.h
> @@ -302,7 +302,7 @@ static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
>  #define __pmd_to_swp_entry(pmd) ((swp_entry_t) { pmd_val(pmd) })
>  #define __swp_entry_to_pmd(x)	((pmd_t) { (x).val | _PAGE_HUGE })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/m68k/include/asm/mcf_pgtable.h b/arch/m68k/include/asm/mcf_pgtable.h
> index 48f87a8a8832..7e9748b29c44 100644
> --- a/arch/m68k/include/asm/mcf_pgtable.h
> +++ b/arch/m68k/include/asm/mcf_pgtable.h
> @@ -274,7 +274,7 @@ extern pgd_t kernel_pg_dir[PTRS_PER_PGD];
>  #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
>  #define __swp_entry_to_pte(x)	(__pte((x).val))
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/m68k/include/asm/motorola_pgtable.h b/arch/m68k/include/asm/motorola_pgtable.h
> index 9866c7acdabe..26da9b985c5f 100644
> --- a/arch/m68k/include/asm/motorola_pgtable.h
> +++ b/arch/m68k/include/asm/motorola_pgtable.h
> @@ -191,7 +191,7 @@ extern pgd_t kernel_pg_dir[128];
>  #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
>  #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/m68k/include/asm/sun3_pgtable.h b/arch/m68k/include/asm/sun3_pgtable.h
> index 30081aee8164..ac0793f57f31 100644
> --- a/arch/m68k/include/asm/sun3_pgtable.h
> +++ b/arch/m68k/include/asm/sun3_pgtable.h
> @@ -175,7 +175,7 @@ extern pgd_t kernel_pg_dir[PTRS_PER_PGD];
>  #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
>  #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/microblaze/include/asm/pgtable.h b/arch/microblaze/include/asm/pgtable.h
> index e4ea2ec3642f..b281c2bbd6c0 100644
> --- a/arch/microblaze/include/asm/pgtable.h
> +++ b/arch/microblaze/include/asm/pgtable.h
> @@ -406,7 +406,7 @@ extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
>  #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) >> 2 })
>  #define __swp_entry_to_pte(x)	((pte_t) { (x).val << 2 })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
> index c29a551eb0ca..c19da4ab7552 100644
> --- a/arch/mips/include/asm/pgtable.h
> +++ b/arch/mips/include/asm/pgtable.h
> @@ -540,7 +540,7 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
>  #endif
>  
>  #if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte.pte_low & _PAGE_SWP_EXCLUSIVE;
>  }
> @@ -557,7 +557,7 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
>  	return pte;
>  }
>  #else
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h
> index eab87c6beacb..64ce06bae8ac 100644
> --- a/arch/nios2/include/asm/pgtable.h
> +++ b/arch/nios2/include/asm/pgtable.h
> @@ -265,7 +265,7 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
>  #define __swp_entry_to_pte(swp)	((pte_t) { (swp).val })
>  #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/openrisc/include/asm/pgtable.h b/arch/openrisc/include/asm/pgtable.h
> index 60c6ce7ff2dc..34cad9177a48 100644
> --- a/arch/openrisc/include/asm/pgtable.h
> +++ b/arch/openrisc/include/asm/pgtable.h
> @@ -413,7 +413,7 @@ static inline void update_mmu_cache_range(struct vm_fault *vmf,
>  #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
>  #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
> index babf65751e81..dfeba45b6d6f 100644
> --- a/arch/parisc/include/asm/pgtable.h
> +++ b/arch/parisc/include/asm/pgtable.h
> @@ -431,7 +431,7 @@ static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
>  #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
>  #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
> index 42c3af90d1f0..92d21c6faf1e 100644
> --- a/arch/powerpc/include/asm/book3s/32/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
> @@ -365,7 +365,7 @@ static inline void __ptep_set_access_flags(struct vm_area_struct *vma,
>  #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) >> 3 })
>  #define __swp_entry_to_pte(x)		((pte_t) { (x).val << 3 })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index 6d98e6f08d4d..dbf772bef20d 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -693,7 +693,7 @@ static inline pte_t pte_swp_mkexclusive(pte_t pte)
>  	return __pte_raw(pte_raw(pte) | cpu_to_be64(_PAGE_SWP_EXCLUSIVE));
>  }
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return !!(pte_raw(pte) & cpu_to_be64(_PAGE_SWP_EXCLUSIVE));
>  }
> diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
> index 8d1f0b7062eb..7d6b9e5b286e 100644
> --- a/arch/powerpc/include/asm/nohash/pgtable.h
> +++ b/arch/powerpc/include/asm/nohash/pgtable.h
> @@ -286,7 +286,7 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
>  	return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
>  }
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index 050fdc49b5ad..433c78c44e02 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -880,7 +880,7 @@ extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
>  #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
>  #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
> index 3ca5af4cfe43..cb86dbf7126a 100644
> --- a/arch/s390/include/asm/pgtable.h
> +++ b/arch/s390/include/asm/pgtable.h
> @@ -913,7 +913,7 @@ static inline int pmd_protnone(pmd_t pmd)
>  }
>  #endif
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/sh/include/asm/pgtable_32.h b/arch/sh/include/asm/pgtable_32.h
> index f939f1215232..5f221f3269e3 100644
> --- a/arch/sh/include/asm/pgtable_32.h
> +++ b/arch/sh/include/asm/pgtable_32.h
> @@ -478,7 +478,7 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
>  /* In both cases, we borrow bit 6 to store the exclusive marker in swap PTEs. */
>  #define _PAGE_SWP_EXCLUSIVE	_PAGE_USER
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte.pte_low & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
> index 62bcafe38b1f..0362f8357371 100644
> --- a/arch/sparc/include/asm/pgtable_32.h
> +++ b/arch/sparc/include/asm/pgtable_32.h
> @@ -353,7 +353,7 @@ static inline swp_entry_t __swp_entry(unsigned long type, unsigned long offset)
>  #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
>  #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & SRMMU_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
> index 2b7f358762c1..65e53491fe07 100644
> --- a/arch/sparc/include/asm/pgtable_64.h
> +++ b/arch/sparc/include/asm/pgtable_64.h
> @@ -1027,7 +1027,7 @@ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
>  #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
>  #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h
> index 5601ca98e8a6..c32309614a15 100644
> --- a/arch/um/include/asm/pgtable.h
> +++ b/arch/um/include/asm/pgtable.h
> @@ -316,7 +316,7 @@ extern pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr);
>  	((swp_entry_t) { pte_val(pte_mkuptodate(pte)) })
>  #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_get_bits(pte, _PAGE_SWP_EXCLUSIVE);
>  }
> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
> index 593f10aabd45..4c7ce40023d3 100644
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -1586,7 +1586,7 @@ static inline pte_t pte_swp_mkexclusive(pte_t pte)
>  	return pte_set_flags(pte, _PAGE_SWP_EXCLUSIVE);
>  }
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_flags(pte) & _PAGE_SWP_EXCLUSIVE;
>  }
> diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
> index 1647a7cc3fbf..6da0aa0604f1 100644
> --- a/arch/xtensa/include/asm/pgtable.h
> +++ b/arch/xtensa/include/asm/pgtable.h
> @@ -355,7 +355,7 @@ ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
>  #define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
>  #define __swp_entry_to_pte(x)	((pte_t) { (x).val })
>  
> -static inline int pte_swp_exclusive(pte_t pte)
> +static inline bool pte_swp_exclusive(pte_t pte)
>  {
>  	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
>  }

I'm not so sure about this implicit cast from unsigned long to bool though.

Is this verified to work correctly on all architectures? I wonder why this
bug was not caught earlier on alpha on the other hand.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Re: [PATCH v2 1/1] mm: pgtable: fix pte_swp_exclusive

[Geert Uytterhoeven]

Hi Adrian,

On Sat, 5 Apr 2025 at 19:22, John Paul Adrian Glaubitz
<glaubitz@physik.fu-berlin.de> wrote:
> On Tue, 2025-02-18 at 18:55 +0100, Magnus Lindholm wrote:
> > Make pte_swp_exclusive return bool instead of int. This will better reflect
> > how pte_swp_exclusive is actually used in the code. This fixes swap/swapoff
> > problems on Alpha due pte_swp_exclusive not returning correct values when
> > _PAGE_SWP_EXCLUSIVE bit resides in upper 32-bits of PTE (like on alpha).
>
> Minor nitpick:
>
> "when _PAGE_SWP_EXCLUSIVE" => "when the _PAGE_SWP_EXCLUSIVE"
>
> >
> > Signed-off-by: Magnus Lindholm <linmag7@gmail.com>

> > --- a/arch/alpha/include/asm/pgtable.h
> > +++ b/arch/alpha/include/asm/pgtable.h
> > @@ -334,7 +334,7 @@ extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
> >  #define __pte_to_swp_entry(pte)      ((swp_entry_t) { pte_val(pte) })
> >  #define __swp_entry_to_pte(x)        ((pte_t) { (x).val })
> >
> > -static inline int pte_swp_exclusive(pte_t pte)
> > +static inline bool pte_swp_exclusive(pte_t pte)
> >  {
> >       return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
> >  }

> > --- a/arch/xtensa/include/asm/pgtable.h
> > +++ b/arch/xtensa/include/asm/pgtable.h
> > @@ -355,7 +355,7 @@ ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
> >  #define __pte_to_swp_entry(pte)      ((swp_entry_t) { pte_val(pte) })
> >  #define __swp_entry_to_pte(x)        ((pte_t) { (x).val })
> >
> > -static inline int pte_swp_exclusive(pte_t pte)
> > +static inline bool pte_swp_exclusive(pte_t pte)
> >  {
> >       return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
> >  }
>
> I'm not so sure about this implicit cast from unsigned long to bool though.
>
> Is this verified to work correctly on all architectures? I wonder why this

Should work fine: any non-zero value is mapped to one.

> bug was not caught earlier on alpha on the other hand.

On Alpha, "pte_val(pte) & _PAGE_SWP_EXCLUSIVE" is either
_PAGE_SWP_EXCLUSIVE == 0x8000000000UL or zero.  Due to the return
type being int, the return value was truncated, and the function always
returned zero.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v2 1/1] mm: pgtable: fix pte_swp_exclusive

[Al Viro]

On Sat, Apr 05, 2025 at 06:09:11PM +0100, Sam James wrote:
> Sam James <sam@gentoo.org> writes:
> 
> > Lovely cleanup and a great suggestion from Al.
> >
> > Reviewed-by: Sam James <sam@gentoo.org>
> >
> > I'd suggest adding a:
> > Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
> 
> Al, were you planning on taking this through your tree?

FWIW, I expected it to get sent to Linus as "please, run this
sed script before -rc1" kind of thing, script being something
like

sed -i -e 's/int pte_swp_exclusive/bool pte_swp_exclusive/' \
	`git grep -l 'int pte_swp_exclusive'`

with suggested commit message...  It's absolutely regular and
that kind of tree-wide change is easier handled that way.

	Oh, well...  To restore the context: Magnus had spotted a fun
bug on Alpha back in February - pte_swp_exclusive() there returned
pte_val(pte) & _PAGE_SWP_EXCLUSIVE as int.  The problem is that
_PAGE_SWP_EXCLUSIVE is 1UL<<39 there, with obvious results...

	I looked at the originally posted patch and suggested to
make pte_swp_exclusive() return bool instead of int.  All users
are in explicitly boolean contexts:

include/linux/swapops.h:        if (pte_swp_exclusive(pte))
mm/debug_vm_pgtable.c:  WARN_ON(pte_swp_exclusive(pte));
mm/debug_vm_pgtable.c:  WARN_ON(!pte_swp_exclusive(pte));
mm/debug_vm_pgtable.c:  WARN_ON(pte_swp_exclusive(pte));
mm/internal.h:  if (pte_swp_exclusive(pte))
mm/memory.c:            if (pte_swp_exclusive(orig_pte)) {
mm/memory.c:            exclusive = pte_swp_exclusive(vmf->orig_pte);
mm/swapfile.c:          if (pte_swp_exclusive(old_pte))
mm/userfaultfd.c:               if (!pte_swp_exclusive(orig_src_pte)) {

	Magnus posted patch of that form (see
https://lore.kernel.org/all/20250218175735.19882-2-linmag7@gmail.com/),
got no serious objections and then it went nowhere.

	Bug is real and fairly obvious, fix is entirely mechanical and
affects one line in each asm/pgtable.h out there.  Linus, could you
run that sed script just before -rc1?  Commit message from the patch refered
above looks sane:

mm: pgtable: fix pte_swp_exclusive

Make pte_swp_exclusive return bool instead of int. This will better reflect
how pte_swp_exclusive is actually used in the code. This fixes swap/swapoff
problems on Alpha due pte_swp_exclusive not returning correct values when
_PAGE_SWP_EXCLUSIVE bit resides in upper 32-bits of PTE (like on alpha).

Signed-off-by: Magnus Lindholm <linmag7@gmail.com>

Re: [PATCH v2 1/1] mm: pgtable: fix pte_swp_exclusive

[Sam James]

Al Viro <viro@zeniv.linux.org.uk> writes:

> On Sat, Apr 05, 2025 at 06:09:11PM +0100, Sam James wrote:
>> Sam James <sam@gentoo.org> writes:
>> 
>> > Lovely cleanup and a great suggestion from Al.
>> >
>> > Reviewed-by: Sam James <sam@gentoo.org>
>> >
>> > I'd suggest adding a:
>> > Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
>> 
>> Al, were you planning on taking this through your tree?
>
> FWIW, I expected it to get sent to Linus as "please, run this
> sed script before -rc1" kind of thing, script being something
> like
>
> sed -i -e 's/int pte_swp_exclusive/bool pte_swp_exclusive/' \
> 	`git grep -l 'int pte_swp_exclusive'`
>
> with suggested commit message...  It's absolutely regular and
> that kind of tree-wide change is easier handled that way.

Ah, sorry. Both Magnus and I are new and irregular kernel contributors,
but I've seen that before and should've thought of it.

> [...]

cheers,
sam