Commit a79390f5 authored by Peter Xu's avatar Peter Xu Committed by Andrew Morton

mm/mprotect: use long for page accountings and retval

Switch to use type "long" for page accountings and retval across the whole
procedure of change_protection().

The change should have shrinked the possible maximum page number to be
half comparing to previous (ULONG_MAX / 2), but it shouldn't overflow on
any system either because the maximum possible pages touched by change
protection should be ULONG_MAX / PAGE_SIZE.

Two reasons to switch from "unsigned long" to "long":

  1. It suites better on count_vm_numa_events(), whose 2nd parameter takes
     a long type.

  2. It paves way for returning negative (error) values in the future.

Currently the only caller that consumes this retval is change_prot_numa(),
where the unsigned long was converted to an int.  Since at it, touching up
the numa code to also take a long, so it'll avoid any possible overflow
too during the int-size convertion.

Link: https://lkml.kernel.org/r/20230104225207.1066932-3-peterx@redhat.comSigned-off-by: default avatarPeter Xu <peterx@redhat.com>
Acked-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Acked-by: default avatarJames Houghton <jthoughton@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 6b7cea90
...@@ -248,7 +248,7 @@ void hugetlb_vma_lock_release(struct kref *kref); ...@@ -248,7 +248,7 @@ void hugetlb_vma_lock_release(struct kref *kref);
int pmd_huge(pmd_t pmd); int pmd_huge(pmd_t pmd);
int pud_huge(pud_t pud); int pud_huge(pud_t pud);
unsigned long hugetlb_change_protection(struct vm_area_struct *vma, long hugetlb_change_protection(struct vm_area_struct *vma,
unsigned long address, unsigned long end, pgprot_t newprot, unsigned long address, unsigned long end, pgprot_t newprot,
unsigned long cp_flags); unsigned long cp_flags);
...@@ -437,7 +437,7 @@ static inline void move_hugetlb_state(struct folio *old_folio, ...@@ -437,7 +437,7 @@ static inline void move_hugetlb_state(struct folio *old_folio,
{ {
} }
static inline unsigned long hugetlb_change_protection( static inline long hugetlb_change_protection(
struct vm_area_struct *vma, unsigned long address, struct vm_area_struct *vma, unsigned long address,
unsigned long end, pgprot_t newprot, unsigned long end, pgprot_t newprot,
unsigned long cp_flags) unsigned long cp_flags)
......
...@@ -2132,7 +2132,7 @@ static inline bool vma_wants_manual_pte_write_upgrade(struct vm_area_struct *vma ...@@ -2132,7 +2132,7 @@ static inline bool vma_wants_manual_pte_write_upgrade(struct vm_area_struct *vma
} }
bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
pte_t pte); pte_t pte);
extern unsigned long change_protection(struct mmu_gather *tlb, extern long change_protection(struct mmu_gather *tlb,
struct vm_area_struct *vma, unsigned long start, struct vm_area_struct *vma, unsigned long start,
unsigned long end, unsigned long cp_flags); unsigned long end, unsigned long cp_flags);
extern int mprotect_fixup(struct mmu_gather *tlb, struct vm_area_struct *vma, extern int mprotect_fixup(struct mmu_gather *tlb, struct vm_area_struct *vma,
......
...@@ -6615,7 +6615,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, ...@@ -6615,7 +6615,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
return i ? i : err; return i ? i : err;
} }
unsigned long hugetlb_change_protection(struct vm_area_struct *vma, long hugetlb_change_protection(struct vm_area_struct *vma,
unsigned long address, unsigned long end, unsigned long address, unsigned long end,
pgprot_t newprot, unsigned long cp_flags) pgprot_t newprot, unsigned long cp_flags)
{ {
...@@ -6624,7 +6624,7 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma, ...@@ -6624,7 +6624,7 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
pte_t *ptep; pte_t *ptep;
pte_t pte; pte_t pte;
struct hstate *h = hstate_vma(vma); struct hstate *h = hstate_vma(vma);
unsigned long pages = 0, psize = huge_page_size(h); long pages = 0, psize = huge_page_size(h);
bool shared_pmd = false; bool shared_pmd = false;
struct mmu_notifier_range range; struct mmu_notifier_range range;
unsigned long last_addr_mask; unsigned long last_addr_mask;
......
...@@ -631,7 +631,7 @@ unsigned long change_prot_numa(struct vm_area_struct *vma, ...@@ -631,7 +631,7 @@ unsigned long change_prot_numa(struct vm_area_struct *vma,
unsigned long addr, unsigned long end) unsigned long addr, unsigned long end)
{ {
struct mmu_gather tlb; struct mmu_gather tlb;
int nr_updated; long nr_updated;
tlb_gather_mmu(&tlb, vma->vm_mm); tlb_gather_mmu(&tlb, vma->vm_mm);
......
...@@ -80,13 +80,13 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr, ...@@ -80,13 +80,13 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
return pte_dirty(pte); return pte_dirty(pte);
} }
static unsigned long change_pte_range(struct mmu_gather *tlb, static long change_pte_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags) unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{ {
pte_t *pte, oldpte; pte_t *pte, oldpte;
spinlock_t *ptl; spinlock_t *ptl;
unsigned long pages = 0; long pages = 0;
int target_node = NUMA_NO_NODE; int target_node = NUMA_NO_NODE;
bool prot_numa = cp_flags & MM_CP_PROT_NUMA; bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
bool uffd_wp = cp_flags & MM_CP_UFFD_WP; bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
...@@ -353,13 +353,13 @@ uffd_wp_protect_file(struct vm_area_struct *vma, unsigned long cp_flags) ...@@ -353,13 +353,13 @@ uffd_wp_protect_file(struct vm_area_struct *vma, unsigned long cp_flags)
} \ } \
} while (0) } while (0)
static inline unsigned long change_pmd_range(struct mmu_gather *tlb, static inline long change_pmd_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pud_t *pud, unsigned long addr, struct vm_area_struct *vma, pud_t *pud, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags) unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{ {
pmd_t *pmd; pmd_t *pmd;
unsigned long next; unsigned long next;
unsigned long pages = 0; long pages = 0;
unsigned long nr_huge_updates = 0; unsigned long nr_huge_updates = 0;
struct mmu_notifier_range range; struct mmu_notifier_range range;
...@@ -367,7 +367,7 @@ static inline unsigned long change_pmd_range(struct mmu_gather *tlb, ...@@ -367,7 +367,7 @@ static inline unsigned long change_pmd_range(struct mmu_gather *tlb,
pmd = pmd_offset(pud, addr); pmd = pmd_offset(pud, addr);
do { do {
unsigned long this_pages; long this_pages;
next = pmd_addr_end(addr, end); next = pmd_addr_end(addr, end);
...@@ -437,13 +437,13 @@ static inline unsigned long change_pmd_range(struct mmu_gather *tlb, ...@@ -437,13 +437,13 @@ static inline unsigned long change_pmd_range(struct mmu_gather *tlb,
return pages; return pages;
} }
static inline unsigned long change_pud_range(struct mmu_gather *tlb, static inline long change_pud_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr, struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags) unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{ {
pud_t *pud; pud_t *pud;
unsigned long next; unsigned long next;
unsigned long pages = 0; long pages = 0;
pud = pud_offset(p4d, addr); pud = pud_offset(p4d, addr);
do { do {
...@@ -458,13 +458,13 @@ static inline unsigned long change_pud_range(struct mmu_gather *tlb, ...@@ -458,13 +458,13 @@ static inline unsigned long change_pud_range(struct mmu_gather *tlb,
return pages; return pages;
} }
static inline unsigned long change_p4d_range(struct mmu_gather *tlb, static inline long change_p4d_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr, struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags) unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{ {
p4d_t *p4d; p4d_t *p4d;
unsigned long next; unsigned long next;
unsigned long pages = 0; long pages = 0;
p4d = p4d_offset(pgd, addr); p4d = p4d_offset(pgd, addr);
do { do {
...@@ -479,14 +479,14 @@ static inline unsigned long change_p4d_range(struct mmu_gather *tlb, ...@@ -479,14 +479,14 @@ static inline unsigned long change_p4d_range(struct mmu_gather *tlb,
return pages; return pages;
} }
static unsigned long change_protection_range(struct mmu_gather *tlb, static long change_protection_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, unsigned long addr, struct vm_area_struct *vma, unsigned long addr,
unsigned long end, pgprot_t newprot, unsigned long cp_flags) unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{ {
struct mm_struct *mm = vma->vm_mm; struct mm_struct *mm = vma->vm_mm;
pgd_t *pgd; pgd_t *pgd;
unsigned long next; unsigned long next;
unsigned long pages = 0; long pages = 0;
BUG_ON(addr >= end); BUG_ON(addr >= end);
pgd = pgd_offset(mm, addr); pgd = pgd_offset(mm, addr);
...@@ -505,12 +505,12 @@ static unsigned long change_protection_range(struct mmu_gather *tlb, ...@@ -505,12 +505,12 @@ static unsigned long change_protection_range(struct mmu_gather *tlb,
return pages; return pages;
} }
unsigned long change_protection(struct mmu_gather *tlb, long change_protection(struct mmu_gather *tlb,
struct vm_area_struct *vma, unsigned long start, struct vm_area_struct *vma, unsigned long start,
unsigned long end, unsigned long cp_flags) unsigned long end, unsigned long cp_flags)
{ {
pgprot_t newprot = vma->vm_page_prot; pgprot_t newprot = vma->vm_page_prot;
unsigned long pages; long pages;
BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL); BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL);
......
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