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authorGerald Schaefer <gerald.schaefer@de.ibm.com>2012-10-08 16:30:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-09 16:22:30 +0900
commit8e72033f2a489b6c98c4e3c7cc281b1afd6cb85c (patch)
tree9ac78daf640471e00f3f0fbe22f6c24fb95b8817 /mm/huge_memory.c
parent46dcde735c9d8953bbd8d105ca6779e5b5300c28 (diff)
thp: make MADV_HUGEPAGE check for mm->def_flags
This adds a check to hugepage_madvise(), to refuse MADV_HUGEPAGE if VM_NOHUGEPAGE is set in mm->def_flags. On s390, the VM_NOHUGEPAGE flag will be set in mm->def_flags for kvm processes, to prevent any future thp mappings. In order to also prevent MADV_HUGEPAGE on such an mm, hugepage_madvise() should check mm->def_flags. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
-rw-r--r--mm/huge_memory.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index bec6243b696..010d32944d1 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1450,6 +1450,8 @@ out:
int hugepage_madvise(struct vm_area_struct *vma,
unsigned long *vm_flags, int advice)
{
+ struct mm_struct *mm = vma->vm_mm;
+
switch (advice) {
case MADV_HUGEPAGE:
/*
@@ -1457,6 +1459,8 @@ int hugepage_madvise(struct vm_area_struct *vma,
*/
if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP))
return -EINVAL;
+ if (mm->def_flags & VM_NOHUGEPAGE)
+ return -EINVAL;
*vm_flags &= ~VM_NOHUGEPAGE;
*vm_flags |= VM_HUGEPAGE;
/*