mm: remove __HAVE_ARCH_PTE_SWP_EXCLUSIVE

__HAVE_ARCH_PTE_SWP_EXCLUSIVE is now supported by all architectures that
support swp PTEs, so let's drop it.

Link: https://lkml.kernel.org/r/20230113171026.582290-27-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pgtable.h
index 970abf5..ba43cb8 100644 (file)
--- a/arch/alpha/include/asm/pgtable.h
+++ b/arch/alpha/include/asm/pgtable.h
@@ -328,7 +328,6 @@ 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 })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 611f412..6e9f8ca 100644 (file)
--- a/arch/arc/include/asm/pgtable-bits-arcv2.h
+++ b/arch/arc/include/asm/pgtable-bits-arcv2.h
@@ -132,7 +132,6 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
 #define __pte_to_swp_entry(pte)                ((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)          ((pte_t) { (x).val })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 886c275..2e626e6 100644 (file)
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -298,7 +298,6 @@ 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)
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 65e7899..575c63d 100644 (file)
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -417,7 +417,6 @@ static inline pgprot_t mk_pmd_sect_prot(pgprot_t prot)
        return __pgprot((pgprot_val(prot) & ~PMD_TABLE_BIT) | PMD_TYPE_SECT);
 }
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline pte_t pte_swp_mkexclusive(pte_t pte)
 {
        return set_pte_bit(pte, __pgprot(PTE_SWP_EXCLUSIVE));

diff --git a/arch/csky/include/asm/pgtable.h b/arch/csky/include/asm/pgtable.h
index 574c97b..d404249 100644 (file)
--- a/arch/csky/include/asm/pgtable.h
+++ b/arch/csky/include/asm/pgtable.h
@@ -200,7 +200,6 @@ static inline pte_t pte_mkyoung(pte_t pte)
        return pte;
 }
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 7eb008e..5939361 100644 (file)
--- a/arch/hexagon/include/asm/pgtable.h
+++ b/arch/hexagon/include/asm/pgtable.h
@@ -397,7 +397,6 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
                (((type & 0x1f) << 1) | \
                 ((offset & 0x3ffff8) << 10) | ((offset & 0x7) << 7)) })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int pte_swp_exclusive(pte_t pte)
 {
        return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;

diff --git a/arch/ia64/include/asm/pgtable.h b/arch/ia64/include/asm/pgtable.h
index e4b8ab9..21c97e3 100644 (file)
--- a/arch/ia64/include/asm/pgtable.h
+++ b/arch/ia64/include/asm/pgtable.h
@@ -424,7 +424,6 @@ extern void paging_init (void);
 #define __pte_to_swp_entry(pte)                ((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)          ((pte_t) { (x).val })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 c6b8fe7..d28fb9d 100644 (file)
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h
@@ -276,7 +276,6 @@ 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 })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 e573d7b..13741c1 100644 (file)
--- a/arch/m68k/include/asm/mcf_pgtable.h
+++ b/arch/m68k/include/asm/mcf_pgtable.h
@@ -275,7 +275,6 @@ 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))
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 c178256..ec0dc19 100644 (file)
--- a/arch/m68k/include/asm/motorola_pgtable.h
+++ b/arch/m68k/include/asm/motorola_pgtable.h
@@ -190,7 +190,6 @@ 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 })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 dbfc970..e582b04 100644 (file)
--- a/arch/m68k/include/asm/sun3_pgtable.h
+++ b/arch/m68k/include/asm/sun3_pgtable.h
@@ -174,7 +174,6 @@ 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 })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 7e3de54..d1b8272 100644 (file)
--- a/arch/microblaze/include/asm/pgtable.h
+++ b/arch/microblaze/include/asm/pgtable.h
@@ -412,7 +412,6 @@ 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 })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 711874c..791389b 100644 (file)
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -528,7 +528,6 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 }
 #endif
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 #if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
 static inline int pte_swp_exclusive(pte_t pte)
 {

diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h
index 05999da..0f5c256 100644 (file)
--- a/arch/nios2/include/asm/pgtable.h
+++ b/arch/nios2/include/asm/pgtable.h
@@ -253,7 +253,6 @@ 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) })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 903b32d..3eb9b95 100644 (file)
--- a/arch/openrisc/include/asm/pgtable.h
+++ b/arch/openrisc/include/asm/pgtable.h
@@ -408,7 +408,6 @@ static inline void update_mmu_cache(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 })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 3033bb8..e2950f5 100644 (file)
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -422,7 +422,6 @@ extern void paging_init (void);
 #define __pte_to_swp_entry(pte)                ((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)          ((pte_t) { (x).val })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 0ecb3a5..7bf1fe7 100644 (file)
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -386,7 +386,6 @@ 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 })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 cb4c67b..4acc969 100644 (file)
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -717,7 +717,6 @@ static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
 }
 #endif /* CONFIG_HAVE_ARCH_SOFT_DIRTY */
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline pte_t pte_swp_mkexclusive(pte_t pte)
 {
        return __pte_raw(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 5f46209..a6caaaa 100644 (file)
--- a/arch/powerpc/include/asm/nohash/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/pgtable.h
@@ -151,7 +151,6 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
        return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
 }
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 03a4728..5b9f409 100644 (file)
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -752,7 +752,6 @@ static inline pmd_t pmdp_establish(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 })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 b26cbf1..2b5db99 100644 (file)
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -812,7 +812,6 @@ static inline int pmd_protnone(pmd_t pmd)
 }
 #endif
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 c34aa79..21952b0 100644 (file)
--- a/arch/sh/include/asm/pgtable_32.h
+++ b/arch/sh/include/asm/pgtable_32.h
@@ -479,7 +479,6 @@ 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
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 abf7a26..d4330e3 100644 (file)
--- a/arch/sparc/include/asm/pgtable_32.h
+++ b/arch/sparc/include/asm/pgtable_32.h
@@ -353,7 +353,6 @@ 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 })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 a1658ee..2dc8d46 100644 (file)
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -989,7 +989,6 @@ 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 })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 cedc5fd..a70d161 100644 (file)
--- a/arch/um/include/asm/pgtable.h
+++ b/arch/um/include/asm/pgtable.h
@@ -313,7 +313,6 @@ 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 })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int 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 d251957..7425f32 100644 (file)
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1299,7 +1299,6 @@ static inline void update_mmu_cache_pud(struct vm_area_struct *vma,
                unsigned long addr, pud_t *pud)
 {
 }
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline pte_t pte_swp_mkexclusive(pte_t pte)
 {
        return pte_set_flags(pte, _PAGE_SWP_EXCLUSIVE);

diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
index 1025e2d..fc7a148 100644 (file)
--- a/arch/xtensa/include/asm/pgtable.h
+++ b/arch/xtensa/include/asm/pgtable.h
@@ -360,7 +360,6 @@ 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 })
 
-#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
 static inline int pte_swp_exclusive(pte_t pte)
 {
        return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 1159b25..5fd4545 100644 (file)
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1064,35 +1064,6 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 #define arch_start_context_switch(prev)        do {} while (0)
 #endif
 
-/*
- * When replacing an anonymous page by a real (!non) swap entry, we clear
- * PG_anon_exclusive from the page and instead remember whether the flag was
- * set in the swp pte. During fork(), we have to mark the entry as !exclusive
- * (possibly shared). On swapin, we use that information to restore
- * PG_anon_exclusive, which is very helpful in cases where we might have
- * additional (e.g., FOLL_GET) references on a page and wouldn't be able to
- * detect exclusivity.
- *
- * These functions don't apply to non-swap entries (e.g., migration, hwpoison,
- * ...).
- */
-#ifndef __HAVE_ARCH_PTE_SWP_EXCLUSIVE
-static inline pte_t pte_swp_mkexclusive(pte_t pte)
-{
-       return pte;
-}
-
-static inline int pte_swp_exclusive(pte_t pte)
-{
-       return false;
-}
-
-static inline pte_t pte_swp_clear_exclusive(pte_t pte)
-{
-       return pte;
-}
-#endif
-
 #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
 #ifndef CONFIG_ARCH_ENABLE_THP_MIGRATION
 static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index ff8d6f6..af59cc7 100644 (file)
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -810,7 +810,6 @@ static void __init pmd_swap_soft_dirty_tests(struct pgtable_debug_args *args) {
 
 static void __init pte_swap_exclusive_tests(struct pgtable_debug_args *args)
 {
-#ifdef __HAVE_ARCH_PTE_SWP_EXCLUSIVE
        unsigned long max_swap_offset;
        swp_entry_t entry, entry2;
        pte_t pte;
@@ -841,7 +840,6 @@ static void __init pte_swap_exclusive_tests(struct pgtable_debug_args *args)
        WARN_ON(!is_swap_pte(pte));
        entry2 = pte_to_swp_entry(pte);
        WARN_ON(memcmp(&entry, &entry2, sizeof(entry)));
-#endif /* __HAVE_ARCH_PTE_SWP_EXCLUSIVE */
 }
 
 static void __init pte_swap_tests(struct pgtable_debug_args *args)

diff --git a/mm/memory.c b/mm/memory.c
index c6bacd5..87b33b4 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3864,10 +3864,6 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
         * the swap entry concurrently) for certainly exclusive pages.
         */
        if (!folio_test_ksm(folio)) {
-               /*
-                * Note that pte_swp_exclusive() == false for architectures
-                * without __HAVE_ARCH_PTE_SWP_EXCLUSIVE.
-                */
                exclusive = pte_swp_exclusive(vmf->orig_pte);
                if (folio != swapcache) {
                        /*

diff --git a/mm/rmap.c b/mm/rmap.c
index 073999f..0d07c50 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1710,17 +1710,6 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
                                page_vma_mapped_walk_done(&pvmw);
                                break;
                        }
-                       /*
-                        * Note: We *don't* remember if the page was mapped
-                        * exclusively in the swap pte if the architecture
-                        * doesn't support __HAVE_ARCH_PTE_SWP_EXCLUSIVE. In
-                        * that case, swapin code has to re-determine that
-                        * manually and might detect the page as possibly
-                        * shared, for example, if there are other references on
-                        * the page or if the page is under writeback. We made
-                        * sure that there are no GUP pins on the page that
-                        * would rely on it, so for GUP pins this is fine.
-                        */
                        if (list_empty(&mm->mmlist)) {
                                spin_lock(&mmlist_lock);
                                if (list_empty(&mm->mmlist))