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 --- 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(-)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 60572d423586e..ca26849a8e359 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -208,7 +208,7 @@ struct page *follow_huge_pgd(struct mm_struct *mm, unsigned long address,
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); @@ -379,7 +379,7 @@ static inline void move_hugetlb_state(struct page *oldpage, { }
-static inline unsigned long hugetlb_change_protection( +static inline long hugetlb_change_protection( struct vm_area_struct *vma, unsigned long address, unsigned long end, pgprot_t newprot) { diff --git a/include/linux/mm.h b/include/linux/mm.h index 3598925561b13..8df1027982532 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1910,7 +1910,7 @@ extern unsigned long move_page_tables(struct vm_area_struct *vma, #define MM_CP_UFFD_WP_ALL (MM_CP_UFFD_WP | \ MM_CP_UFFD_WP_RESOLVE)
-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, unsigned long cp_flags); extern int mprotect_fixup(struct vm_area_struct *vma, diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 70ceac102a8db..d583f9394be5f 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5644,7 +5644,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, 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, pgprot_t newprot) { struct mm_struct *mm = vma->vm_mm; @@ -5652,7 +5652,7 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma, 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;
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index f089de8564cad..3d984d070e3fe 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -634,7 +634,7 @@ static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask, 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, MM_CP_PROT_NUMA); if (nr_updated) diff --git a/mm/mprotect.c b/mm/mprotect.c index ed18dc49533f6..58822900c6d65 100644 --- 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, 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 dirty_accountable = cp_flags & MM_CP_DIRTY_ACCT; bool prot_numa = cp_flags & MM_CP_PROT_NUMA; @@ -219,13 +219,13 @@ static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd) 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, 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;
@@ -233,7 +233,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
pmd = pmd_offset(pud, addr); do { - unsigned long this_pages; + long this_pages;
next = pmd_addr_end(addr, end);
@@ -291,13 +291,13 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma, 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, unsigned long cp_flags) { pud_t *pud; unsigned long next; - unsigned long pages = 0; + long pages = 0;
pud = pud_offset(p4d, addr); do { @@ -311,13 +311,13 @@ static inline unsigned long change_pud_range(struct vm_area_struct *vma, 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, unsigned long cp_flags) { p4d_t *p4d; unsigned long next; - unsigned long pages = 0; + long pages = 0;
p4d = p4d_offset(pgd, addr); do { @@ -331,7 +331,7 @@ static inline unsigned long change_p4d_range(struct vm_area_struct *vma, 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, unsigned long cp_flags) { @@ -339,7 +339,7 @@ static unsigned long change_protection_range(struct vm_area_struct *vma, 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); @@ -361,11 +361,11 @@ static unsigned long change_protection_range(struct vm_area_struct *vma, 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, unsigned long cp_flags) { - unsigned long pages; + long pages;
BUG_ON((cp_flags & MM_CP_UFFD_WP_ALL) == MM_CP_UFFD_WP_ALL);