Messages in this thread | | | Subject | Re: [PATCH scsi-misc-2.6 08/08] scsi: fix hot unplug sequence | From | James Bottomley <> | Date | Fri, 25 Mar 2005 13:19:48 -0600 |
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On Fri, 2005-03-25 at 14:38 +0900, Tejun Heo wrote: > We have users of scsi_do_req() other than scsi_wait_req() and they > use different done() functions to do different things. I've checked > other done functions and none uses contents inside the passed > scsi_cmnd, so using a dummy command should be okay with them. Am I > missing something here?
Well ... the other users are supposed to be going away. They're actually all coded wrongly in some way or other ... perhaps I should speed up the process.
> Oh, and I would really appreciate if you can fill me in / give a > pointer about the scsi_request/scsi_cmnd distinction.
The block layer speaks in terms of requests and the scsi layers in terms of commands. The scsi_request_fn() actually associates a request with a command. However, since SCSI uses the block layer for queueing, all the internal scsi command submit paths have to use requests. This is what a scsi_request is. The reason for the special casing is that we can't use the normal REQ_CMD or REQ_BLOCK_PC paths because they need ULD initialisation and back end processing.
James
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