diff options
Diffstat (limited to 'mm/mlock.c')
| -rw-r--r-- | mm/mlock.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/mm/mlock.c b/mm/mlock.c index b70919ce4f72..4f318642fbbe 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -171,7 +171,12 @@ static long __mlock_vma_pages_range(struct vm_area_struct *vma, VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem)); gup_flags = FOLL_TOUCH | FOLL_GET; - if (vma->vm_flags & VM_WRITE) + /* + * We want to touch writable mappings with a write fault in order + * to break COW, except for shared mappings because these don't COW + * and we would not want to dirty them for nothing. + */ + if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE) gup_flags |= FOLL_WRITE; /* We don't try to access the guard page of a stack vma */ |