[dm-devel] [PATCH 05/18] block: allow specifying size for extra command data

[Bart Van Assche]

On Fri, 2017-01-27 at 10:26 -0700, Jens Axboe wrote:
> On 01/27/2017 10:21 AM, Bart Van Assche wrote:
> > On Fri, 2017-01-27 at 17:12 +0100, Christoph Hellwig wrote:
> > > On Wed, Jan 25, 2017 at 10:15:55PM -0500, Martin K. Petersen wrote:
> > > > +static void *alloc_request_size(gfp_t gfp_mask, void *data)
> > > > 
> > > > I like alloc_request_simple() but alloc_request_size() seems a bit
> > > > contrived. _reserve? _extra? _special? Don't have any good suggestions,
> > > > I'm afraid.
> > > 
> > > Not that I'm a fan of _size, but I like the other suggestions even less.
> > 
> > Hello Christoph and Martin,
> > 
> > How about using the function names alloc_full_request() / free_full_request()
> > together with a comment that mentions that cmd_size is set by the LLD?
> 
> Since we use pdu in other places, how about alloc_request_pdu() or
> alloc_request_with_pdu()?
> 
> And since it's all queued up, any bike shedding changes will have to be
> incremental.

Hello Jens,

Other Linux subsystems use the term "private data" instead of PDU. How about
modifying the block layer such that it uses the same terminology? I'm
referring to function names like blk_mq_rq_from_pdu() and blk_mq_rq_to_pdu()

Thanks,

Bart.