This optimization does not work with the locking.
Fixes: f12fee814843 (mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap())
Suggested-by: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
mm/mmap.c | 61 ++-----------------------------------------------------
1 file changed, 2 insertions(+), 59 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 2f19976ea817..4fc1b3098c91 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2861,67 +2861,10 @@ static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma,
struct list_head *uf)
{
struct mm_struct *mm = vma->vm_mm;
- struct vm_area_struct unmap;
- unsigned long unmap_pages;
- int ret = 1;
+ int ret;
arch_unmap(mm, newbrk, oldbrk);
-
- if (likely((vma->vm_end < oldbrk) ||
- ((vma->vm_start == newbrk) && (vma->vm_end == oldbrk)))) {
- /* remove entire mapping(s) */
- mas_set(mas, newbrk);
- if (vma->vm_start != newbrk)
- mas_reset(mas); /* cause a re-walk for the first overlap. */
- ret = __do_munmap(mm, newbrk, oldbrk - newbrk, uf, true);
- goto munmap_full_vma;
- }
-
- vma_init(&unmap, mm);
- unmap.vm_start = newbrk;
- unmap.vm_end = oldbrk;
- ret = userfaultfd_unmap_prep(&unmap, newbrk, oldbrk, uf);
- if (ret)
- return ret;
- ret = 1;
-
- /* Change the oldbrk of vma to the newbrk of the munmap area */
- vma_adjust_trans_huge(vma, vma->vm_start, newbrk, 0);
- if (mas_preallocate(mas, vma, GFP_KERNEL))
- return -ENOMEM;
-
- if (vma->anon_vma) {
- anon_vma_lock_write(vma->anon_vma);
- anon_vma_interval_tree_pre_update_vma(vma);
- }
-
- vma->vm_end = newbrk;
- vma_init(&unmap, mm);
- unmap.vm_start = newbrk;
- unmap.vm_end = oldbrk;
- if (vma->anon_vma)
- vma_set_anonymous(&unmap);
-
- vma_mas_remove(&unmap, mas);
-
- vmacache_invalidate(vma->vm_mm);
- if (vma->anon_vma) {
- anon_vma_interval_tree_post_update_vma(vma);
- anon_vma_unlock_write(vma->anon_vma);
- }
-
- unmap_pages = vma_pages(&unmap);
- if (vma->vm_flags & VM_LOCKED)
- mm->locked_vm -= unmap_pages;
-
- mmap_write_downgrade(mm);
- unmap_region(mm, &unmap, vma, newbrk, oldbrk);
- /* Statistics */
- vm_stat_account(mm, vma->vm_flags, -unmap_pages);
- if (vma->vm_flags & VM_ACCOUNT)
- vm_unacct_memory(unmap_pages);
-
-munmap_full_vma:
+ ret = __do_munmap(mm, newbrk, oldbrk - newbrk, uf, true);
validate_mm_mt(mm);
return ret;
}
--
2.35.1
