Re: [PATCH 2/2] block: move direct_IO into our own read_iter handler

On Fri, Dec 03, 2021 at 08:38:29AM -0700, Jens Axboe wrote:

Don't call into generic_file_read_iter() if we know it's O_DIRECT, just
set it up ourselves and call our own handler. This avoids an indirect call
for O_DIRECT.

Fall back to filemap_read() if we fail.

Please also do it for the write side, having a partial ->direct_IO is a
really bad idea.