[dm-devel] New -udm?

[Mike Christie]

Lars Marowsky-Bree wrote:
> On 2005-04-10T18:14:44, Dave Olien <dmo at osdl.org> wrote:
> 
> 
>>You're correct.  I'll rewrite it on Thursday this week.
>>I'll use the same methods Lars used in the dm-emc.c
> 
> 
> Note that dm-emc.c also would need to pre-allocate it's requests, but
> doesn't right now :/
> 
> Pre-allocating the requests sucks: Either we pre-allocate for _every_
> path we might potentially need to send the request down on, or fix up
> the request for the path we sent it down on (which would require us to
> use internal knowledge about the req structs we're not supposed to
> have).

what is wrong with what you have now where you utilize the queue/path's 
mempool by doing a blk_get_request with GFP_WAIT? Is that "fix up the 
request..." comment meaning that you do not like to access the request 
structure for that code, or was it meaning that you have one request 
that is shared across paths and it needs to be cleaned up for reuse.

I think the hw_handlers setting up the requests is not so fun. Maybe the 
block layer scsi_ioctl code could be reworked a little so that it could 
set some of that up for us since it is very similar. My hw handler was 
basically cutting and pasting of that code with some large 
simplifcations. I am working on a Target Port Group handler that is 
again cutting and pasting more code.

> 
> Good solutions solicited ;-)
> 
> 
> Sincerely,
>     Lars Marowsky-Brée <lmb at suse.de>
>