iomap: move the iomap_dio_rw ->end_io callback into a structure

Add a new iomap_dio_ops structure that for now just contains the end_io
handler.  This avoid storing the function pointer in a mutable structure,
which is a possible exploit vector for kernel code execution, and prepares
for adding a submit_io handler that btrfs needs.

Signed-off-by: Christoph Hellwig <>
Reviewed-by: Darrick J. Wong <>
Signed-off-by: Darrick J. Wong <>
3 files changed