New code for 5.10:
- Don't WARN_ON weird states that unprivileged users can create.
- Don't invalidate page cache when direct writes want to fall back to
  buffered.
- Fix some problems when readahead ios fail.
- Fix a problem where inline data pages weren't getting flushed during
  an unshare operation.
- Rework iomap to support arbitrarily many blocks per page in
  preparation to support THP for the page cache.
iomap: Change calling convention for zeroing

Pass the full length to iomap_zero() and dax_iomap_zero(), and have
them return how many bytes they actually handled.  This is preparatory
work for handling THP, although it looks like DAX could actually take
advantage of it if there's a larger contiguous area.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
3 files changed