Deduplicate io_*_prep calls?

[Andres Freund <andres@anarazel.de>]

Hi,

There's currently two places that know to call io_*_prep() for
sqes. io_req_defer_prep() and io_issue_sqe(). E.g. for READV there's:

static int io_req_defer_prep(struct io_kiocb *req,
			     const struct io_uring_sqe *sqe)
...
	case IORING_OP_READV:
	case IORING_OP_READ_FIXED:
	case IORING_OP_READ:
		ret = io_read_prep(req, sqe, true);
		break;

and

static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
			struct io_kiocb **nxt, bool force_nonblock)
{
...
	case IORING_OP_READV:
	case IORING_OP_READ_FIXED:
	case IORING_OP_READ:
		if (sqe) {
			ret = io_read_prep(req, sqe, force_nonblock);
			if (ret < 0)
				break;
		}
		ret = io_read(req, nxt, force_nonblock);
		break;

that seems a bit unnecessary. How about breaking that out into a
separate function?  I can write up a patch, just didn't want to do so if
there's a reason for the current split.


Alternatively it'd could all be just be dispatches via io_op_defs, but
that'd be a bigger change with potential performance implications. And
it'd benefit from prior deduplication anyway.

Greetings,

Andres Freund