Messages in this thread | | | Date | Fri, 24 Apr 2009 23:17:50 +0400 | From | Vladislav Bolkhovitin <> | Subject | Re: [PATCH] [Target_Core_Mod/pSCSI]: Add optional legacy scsi_execute_async() usage for Linux/SCSI passthrough |
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Boaz Harrosh, on 04/22/2009 05:24 PM wrote: > On 04/21/2009 03:15 PM, Vladislav Bolkhovitin wrote: >> Boaz Harrosh, on 04/19/2009 02:56 PM wrote: >>> On 04/17/2009 04:09 AM, Nicholas A. Bellinger wrote: >> [..] >> >>> Are you aware that scsi_execute_async() has gone in 2.6.30-rc1? >>> >>> I'm not sure what would be the best alternative for you. I would say >>> a bio, but it is still being debated. Your current options are: >>> >>> 1. bio_alloc then loop () bio_add_pc_page, and finally blk_rq_append_bio >>> (Which block people don't like) >>> 2. sglist => page-pointers-array translation and blk_rq_map_user with >>> struct rq_map_data mode. (not possible with all kind of sglists) >>> 2. sglist => iovec translation and blk_rq_map_user_iov() >>> (Very very ugly mapping of pages to virtual pointers) >>> >>> I have a similar situation with my OSD code. >> Do you have somewhere in it a need to run an arbitrary CDB with data >> pages stored in an sglist? Is that code accepted in the mainline? >> > > No, I have a direct bio which comes from two sources. > 1. A bio prepared by a filesystem to describe a write/read to a file (osd object) > 2. A cloned bio that comes from a stacking block-device over osd-object. > > So I do not have an sglist at all, anywhere in code. > >> If yes, why not to resurrect the necessary bits of scsi_execute_async() >> (option (1) above)? It was deleted, because in 2.6.30 there are no users >> of it left, but if there are users (OSD), then why not to return it? >> Seems nothing better for the sg->bio case can be invented. >> > > I hate scsi_execute_async() for lots of reasons, > 1. The cover-up of an historical abuse of sglists by sg/sr > 2. Override of use_sg/data-pointer crap > 3. What is data-format got to do with sync/async execution > 4. the need of all that scsi_io_context and the re-invention > of async_done API. > 5. ... > Good riddence
Removal of what can be removed from the above I meant under "the necessary bits".
> But you might be looking into an API introduced by an RFC by > Tejun Heo in the form of blk_rq_map_kern_sgl() which should > be a more appropriate general API for your use.
Yes, it looks like what's needed.
> (And is not directly usable for me in OSD) > >> Vlad > > Boaz > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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