5.4-stable review patch. If anyone has any objections, please let me know.
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From: Peter Xu peterx@redhat.com
commit a79390f5d6a78647fd70856bd42b22d994de0ba2 upstream.
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 [ Adjust context ] Signed-off-by: Harry Yoo harry.yoo@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/hugetlb.h | 4 ++-- include/linux/mm.h | 2 +- mm/hugetlb.c | 4 ++-- mm/mempolicy.c | 2 +- mm/mprotect.c | 26 +++++++++++++------------- 5 files changed, 19 insertions(+), 19 deletions(-)
--- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -137,7 +137,7 @@ struct page *follow_huge_pgd(struct mm_s
int pmd_huge(pmd_t pmd); 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);
bool is_hugetlb_entry_migration(pte_t pte); @@ -195,7 +195,7 @@ static inline bool isolate_huge_page(str #define putback_active_hugepage(p) do {} while (0) #define move_hugetlb_state(old, new, reason) do {} while (0)
-static inline unsigned long hugetlb_change_protection(struct vm_area_struct *vma, +static inline long hugetlb_change_protection(struct vm_area_struct *vma, unsigned long address, unsigned long end, pgprot_t newprot) { return 0; --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1657,7 +1657,7 @@ extern unsigned long move_page_tables(st unsigned long old_addr, struct vm_area_struct *new_vma, unsigned long new_addr, unsigned long len, bool need_rmap_locks); -extern unsigned long change_protection(struct vm_area_struct *vma, unsigned long start, +extern long change_protection(struct vm_area_struct *vma, unsigned long start, unsigned long end, pgprot_t newprot, int dirty_accountable, int prot_numa); extern int mprotect_fixup(struct vm_area_struct *vma, --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4635,7 +4635,7 @@ same_page: #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) #endif
-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) { struct mm_struct *mm = vma->vm_mm; @@ -4643,7 +4643,7 @@ unsigned long hugetlb_change_protection( pte_t *ptep; pte_t pte; struct hstate *h = hstate_vma(vma); - unsigned long pages = 0; + long pages = 0; bool shared_pmd = false; struct mmu_notifier_range range;
--- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -595,7 +595,7 @@ unlock: unsigned long change_prot_numa(struct vm_area_struct *vma, unsigned long addr, unsigned long end) { - int nr_updated; + long nr_updated;
nr_updated = change_protection(vma, addr, end, PAGE_NONE, 0, 1); if (nr_updated) --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -35,13 +35,13 @@
#include "internal.h"
-static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, +static long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, unsigned long end, pgprot_t newprot, int dirty_accountable, int prot_numa) { pte_t *pte, oldpte; spinlock_t *ptl; - unsigned long pages = 0; + long pages = 0; int target_node = NUMA_NO_NODE;
/* @@ -186,13 +186,13 @@ static inline int pmd_none_or_clear_bad_ return 0; }
-static inline unsigned long change_pmd_range(struct vm_area_struct *vma, +static inline long change_pmd_range(struct vm_area_struct *vma, pud_t *pud, unsigned long addr, unsigned long end, pgprot_t newprot, int dirty_accountable, int prot_numa) { pmd_t *pmd; unsigned long next; - unsigned long pages = 0; + long pages = 0; unsigned long nr_huge_updates = 0; struct mmu_notifier_range range;
@@ -200,7 +200,7 @@ static inline unsigned long change_pmd_r
pmd = pmd_offset(pud, addr); do { - unsigned long this_pages; + long this_pages;
next = pmd_addr_end(addr, end);
@@ -258,13 +258,13 @@ next: return pages; }
-static inline unsigned long change_pud_range(struct vm_area_struct *vma, +static inline long change_pud_range(struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr, unsigned long end, pgprot_t newprot, int dirty_accountable, int prot_numa) { pud_t *pud; unsigned long next; - unsigned long pages = 0; + long pages = 0;
pud = pud_offset(p4d, addr); do { @@ -278,13 +278,13 @@ static inline unsigned long change_pud_r return pages; }
-static inline unsigned long change_p4d_range(struct vm_area_struct *vma, +static inline long change_p4d_range(struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr, unsigned long end, pgprot_t newprot, int dirty_accountable, int prot_numa) { p4d_t *p4d; unsigned long next; - unsigned long pages = 0; + long pages = 0;
p4d = p4d_offset(pgd, addr); do { @@ -298,7 +298,7 @@ static inline unsigned long change_p4d_r return pages; }
-static unsigned long change_protection_range(struct vm_area_struct *vma, +static long change_protection_range(struct vm_area_struct *vma, unsigned long addr, unsigned long end, pgprot_t newprot, int dirty_accountable, int prot_numa) { @@ -306,7 +306,7 @@ static unsigned long change_protection_r pgd_t *pgd; unsigned long next; unsigned long start = addr; - unsigned long pages = 0; + long pages = 0;
BUG_ON(addr >= end); pgd = pgd_offset(mm, addr); @@ -328,11 +328,11 @@ static unsigned long change_protection_r return pages; }
-unsigned long change_protection(struct vm_area_struct *vma, unsigned long start, +long change_protection(struct vm_area_struct *vma, unsigned long start, unsigned long end, pgprot_t newprot, int dirty_accountable, int prot_numa) { - unsigned long pages; + long pages;
if (is_vm_hugetlb_page(vma)) pages = hugetlb_change_protection(vma, start, end, newprot);