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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/hugetlb.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/hugetlb.c')
-rw-r--r--mm/hugetlb.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a82f41024167..a0d6d0980064 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6615,7 +6615,7 @@ 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, unsigned long cp_flags)
{
@@ -6624,7 +6624,7 @@ 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, psize = huge_page_size(h);
+ long pages = 0, psize = huge_page_size(h);
bool shared_pmd = false;
struct mmu_notifier_range range;
unsigned long last_addr_mask;