On Mon, Nov 14, 2016 at 10:52:50AM -0500, Johannes Weiner wrote: > On Mon, Nov 14, 2016 at 05:29:02PM +0300, Kirill A. Shutemov wrote: > > @@ -1400,7 +1400,9 @@ static void collapse_shmem(struct mm_struct *mm, > > PAGE_SIZE, 0); > > > > spin_lock_irq(&mapping->tree_lock); > > - > > + slot = radix_tree_lookup_slot(&mapping->page_tree, index); > > + VM_BUG_ON_PAGE(page != radix_tree_deref_slot_protected(slot, > > + &mapping->tree_lock), page); > > VM_BUG_ON_PAGE(page_mapped(page), page); > > That looks good to me. The slot may get relocated, but the content > shouldn't change with the page locked. > > Are you going to send a full patch with changelog and sign-off? If so, > please add: > > Acked-by: Johannes Weiner <[email protected]>
Just to clarify, this is in addition to my radix_tree_iter_next() change. The iterator still needs to be reloaded because the number of valid slots that come after the current one can change as well.
