This prepares the function to copy a vma between two processes. Two new arguments are introduced.
Signed-off-by: Kirill Tkhai <[email protected]> --- include/linux/mm.h | 4 ++-- mm/mmap.c | 33 ++++++++++++++++++++++++--------- mm/mremap.c | 4 ++-- 3 files changed, 28 insertions(+), 13 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 0e8834ac32b7..afe07e4a76f8 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2329,8 +2329,8 @@ extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *, struct rb_node **, struct rb_node *); extern void unlink_file_vma(struct vm_area_struct *); extern struct vm_area_struct *copy_vma(struct vm_area_struct **, - unsigned long addr, unsigned long len, pgoff_t pgoff, - bool *need_rmap_locks); + struct mm_struct *, unsigned long addr, unsigned long len, + pgoff_t pgoff, bool *need_rmap_locks, bool clear_flags_ctx); extern void exit_mmap(struct mm_struct *); static inline int check_data_rlimit(unsigned long rlim, diff --git a/mm/mmap.c b/mm/mmap.c index 57803a0a3a5c..99778e724ad1 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -3195,19 +3195,21 @@ int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) } /* - * Copy the vma structure to a new location in the same mm, - * prior to moving page table entries, to effect an mremap move. + * Copy the vma structure to new location in the same vma + * prior to moving page table entries, to effect an mremap move; */ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, - unsigned long addr, unsigned long len, pgoff_t pgoff, - bool *need_rmap_locks) + struct mm_struct *mm, unsigned long addr, + unsigned long len, pgoff_t pgoff, + bool *need_rmap_locks, bool clear_flags_ctx) { struct vm_area_struct *vma = *vmap; unsigned long vma_start = vma->vm_start; - struct mm_struct *mm = vma->vm_mm; + struct vm_userfaultfd_ctx uctx; struct vm_area_struct *new_vma, *prev; struct rb_node **rb_link, *rb_parent; bool faulted_in_anon_vma = true; + unsigned long flags; /* * If anonymous vma has not yet been faulted, update new pgoff @@ -3220,15 +3222,25 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) return NULL; /* should never get here */ - new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, - vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), - vma->vm_userfaultfd_ctx); + + uctx = vma->vm_userfaultfd_ctx; + flags = vma->vm_flags; + if (clear_flags_ctx) { + uctx = NULL_VM_UFFD_CTX; + flags &= ~(VM_UFFD_MISSING | VM_UFFD_WP | VM_MERGEABLE | + VM_LOCKED | VM_LOCKONFAULT | VM_WIPEONFORK | + VM_DONTCOPY); + } + + new_vma = vma_merge(mm, prev, addr, addr + len, flags, vma->anon_vma, + vma->vm_file, pgoff, vma_policy(vma), uctx); if (new_vma) { /* * Source vma may have been merged into new_vma */ if (unlikely(vma_start >= new_vma->vm_start && - vma_start < new_vma->vm_end)) { + vma_start < new_vma->vm_end) && + vma->vm_mm == mm) { /* * The only way we can get a vma_merge with * self during an mremap is if the vma hasn't @@ -3249,6 +3261,9 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, new_vma = vm_area_dup(vma); if (!new_vma) goto out; + new_vma->vm_mm = mm; + new_vma->vm_flags = flags; + new_vma->vm_userfaultfd_ctx = uctx; new_vma->vm_start = addr; new_vma->vm_end = addr + len; new_vma->vm_pgoff = pgoff; diff --git a/mm/mremap.c b/mm/mremap.c index 37b5b2ad91be..9a96cfc28675 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -352,8 +352,8 @@ static unsigned long move_vma(struct vm_area_struct *vma, return err; new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT); - new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff, - &need_rmap_locks); + new_vma = copy_vma(&vma, mm, new_addr, new_len, new_pgoff, + &need_rmap_locks, false); if (!new_vma) return -ENOMEM;
