Messages in this thread | | | Date | Thu, 9 Aug 2012 18:26:34 -0700 (PDT) | From | Hugh Dickins <> | Subject | Re: [patch] mmap: feed back correct prev vma when finding vma |
| |
On Thu, 9 Aug 2012, Hillf Danton wrote: > After walking rb tree, if vma is determined, prev vma has to be determined > based on vma; and rb_prev should be considered only if no vma determined.
Why? Because you think more code is better code? I disagree.
If you have seen a bug here, please tell how to reproduce it.
I have not heard of a bug here: I think you're saying, if the rbtree were inconsistent with the vma list, then you think it would be a good idea to believe the vma list instead of the rbtree where there's a choice.
But the rbtree had better not be inconsistent with the vma list.
Hugh
> > Signed-off-by: Hillf Danton <dhillf@gmail.com> > --- > > --- a/mm/mmap.c Fri Aug 3 07:38:10 2012 > +++ b/mm/mmap.c Mon Aug 6 20:10:18 2012 > @@ -385,9 +385,13 @@ find_vma_prepare(struct mm_struct *mm, u > } > } > > - *pprev = NULL; > - if (rb_prev) > - *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); > + if (vma) { > + *pprev = vma->vm_prev; > + } else { > + *pprev = NULL; > + if (rb_prev) > + *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); > + } > *rb_link = __rb_link; > *rb_parent = __rb_parent; > return vma; > --
| |