* Matthew Wilcox <willy@xxxxxxxxxxxxx> [230921 14:40]: > On Thu, Sep 21, 2023 at 02:12:36PM -0400, Liam R. Howlett wrote: > > Since MAS_NONE is used for handling of the maple tree when it's a single > > entry at 0 (just a pointer), changing the handling of MAS_NONE in > > mas_find() would make the code more complicated and error prone. > > Single entry at index 0 is MAS_ROOT, not MAS_NONE. Ah, sorry. I didn't explain this well. We end up in MAS_NONE when we search from MAS_ROOT upwards.. that is, there's a value only at 0 and we request 1 - ULONG_MAX, or we've called mas_find() with an index > 0. So there is no node in the tree for this entry. The complication arises when mas_prev(), mas_next() or mas_walk()/mas_find() has already set MAS_NONE, then we can't tell the difference and so we don't really know what the Right Thing to do would be.
