From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Christie Subject: Re: New -udm? Date: Mon, 11 Apr 2005 02:27:11 -0700 Message-ID: <425A42EF.50808@us.ibm.com> References: <20050410192934.GP12752@marowsky-bree.de> <1113164717.8372.2.camel@zezette> <4259B895.4070600@us.ibm.com> <20050411011444.GA3748@osdl.org> <20050411084611.GA12752@marowsky-bree.de> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20050411084611.GA12752@marowsky-bree.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development Cc: Alasdair G Kergon List-Id: dm-devel.ids Lars Marowsky-Bree wrote: > On 2005-04-10T18:14:44, Dave Olien wrote: >=20 >=20 >>You're correct. I'll rewrite it on Thursday this week. >>I'll use the same methods Lars used in the dm-emc.c >=20 >=20 > Note that dm-emc.c also would need to pre-allocate it's requests, but > doesn't right now :/ >=20 > 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=20 mempool by doing a blk_get_request with GFP_WAIT? Is that "fix up the=20 request..." comment meaning that you do not like to access the request=20 structure for that code, or was it meaning that you have one request=20 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=20 block layer scsi_ioctl code could be reworked a little so that it could=20 set some of that up for us since it is very similar. My hw handler was=20 basically cutting and pasting of that code with some large=20 simplifcations. I am working on a Target Port Group handler that is=20 again cutting and pasting more code. >=20 > Good solutions solicited ;-) >=20 >=20 > Sincerely, > Lars Marowsky-Br=E9e >=20