On Mon, Jan 16, 2023 at 04:01:50PM +0000, David Howells wrote: > Hi Jens, Christoph, > > Do you know if there's a reason why REQ_OP_READ has to be 0? I'm seeing a > circumstance where a direct I/O write on a blockdev is BUG'ing in my modified > iov_iter code because the iterator says it's a source iterator (correct), but > the bio->bi_opf == REQ_OP_READ (which should be wrong). > > I thought I'd move REQ_OP_READ to, say, 4 so that I could try and see if it's > just undefined but the kernel BUGs and then panics during boot. There's all kind of assumptions of that from basically day 1 of Linux. The most obvious one is in op_is_write, but I'm pretty sure there are more hidden somewhere.
