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authorPeter Xu <peterx@redhat.com>2023-01-05 01:52:06 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-01-19 04:12:53 +0300
commita79390f5d6a78647fd70856bd42b22d994de0ba2 (patch)
tree4b6528a12bf5bcab1ca80b47029b286f80268f0d /mm/mprotect.c
parent6b7cea90c82e104c1151fec1f3ee216997fda652 (diff)
downloadlinux-a79390f5d6a78647fd70856bd42b22d994de0ba2.tar.xz
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.com Signed-off-by: Peter Xu <peterx@redhat.com> Acked-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: James 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: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/mprotect.c')
-rw-r--r--mm/mprotect.c26
1 files changed, 13 insertions, 13 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 71358e45a742..0af22ab59ea8 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -80,13 +80,13 @@ bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
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,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
pte_t *pte, oldpte;
spinlock_t *ptl;
- unsigned long pages = 0;
+ long pages = 0;
int target_node = NUMA_NO_NODE;
bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
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)
} \
} 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,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
pmd_t *pmd;
unsigned long next;
- unsigned long pages = 0;
+ long pages = 0;
unsigned long nr_huge_updates = 0;
struct mmu_notifier_range range;
@@ -367,7 +367,7 @@ static inline unsigned long change_pmd_range(struct mmu_gather *tlb,
pmd = pmd_offset(pud, addr);
do {
- unsigned long this_pages;
+ long this_pages;
next = pmd_addr_end(addr, end);
@@ -437,13 +437,13 @@ next:
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,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
pud_t *pud;
unsigned long next;
- unsigned long pages = 0;
+ long pages = 0;
pud = pud_offset(p4d, addr);
do {
@@ -458,13 +458,13 @@ static inline unsigned long change_pud_range(struct mmu_gather *tlb,
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,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
p4d_t *p4d;
unsigned long next;
- unsigned long pages = 0;
+ long pages = 0;
p4d = p4d_offset(pgd, addr);
do {
@@ -479,14 +479,14 @@ static inline unsigned long change_p4d_range(struct mmu_gather *tlb,
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,
unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{
struct mm_struct *mm = vma->vm_mm;
pgd_t *pgd;
unsigned long next;
- unsigned long pages = 0;
+ long pages = 0;
BUG_ON(addr >= end);
pgd = pgd_offset(mm, addr);
@@ -505,12 +505,12 @@ static unsigned long change_protection_range(struct mmu_gather *tlb,
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,
unsigned long end, unsigned long cp_flags)
{
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);