Re: [PATCH 1/2] io_uring: Pass whole sqe to commands

[Christoph Hellwig]

On Thu, Apr 20, 2023 at 05:29:18AM -0700, Breno Leitao wrote:
> > > -	cmd_size = uring_cmd_pdu_size(req->ctx->flags & IORING_SETUP_SQE128);
> > > +	if (req->ctx->flags & IORING_SETUP_SQE128)
> > > +		size <<= 1;
> > 
> > 
> > Why does this stop using uring_cmd_pdu_size()?
> 
> Before, only the cmd payload (sqe->cmd) was being copied to the async
> structure. We are copying over the whole sqe now, since we can use SQE
> fields inside the ioctl callbacks (instead of only cmd fields). So, the
> copy now is 64 bytes for single SQE or 128 for double SQEs.

That's the point of this series and I get it.  But why do we remove
the nice and self-documenting helper that returns once or twice
the sizeof of the SQE structure and instead add a magic open coded
left shift?