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 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. (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@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
