On Mon, Mar 17 2008 at 12:55 +0200, FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> wrote: > On Fri, 14 Mar 2008 10:24:12 -0400 > Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > >> On Fri, Mar 14, 2008 at 02:51:35PM +0100, Jens Axboe wrote: >>> Are you sure? Seems to me that st builds its own list with >>> get_user_pages() for direct io, where will that get bounced? The block >>> layer will only bounce things that are mapped directly, so if st used >>> blk_rq_map_kern() and inserted that request in the queue, we could >>> proceed with killing that check in st. >> Which shouldn't be all too difficult and would be the right thing to >> do. We really need someone to sit down and convert st/osst/sg to use >> the proper block layer helpers. > > I've been working on this (hopefully, I'll submit an updated patchset > this week). > > I think that the main problem was a lack of motivation for these > changes. I bet that nobody reviewed the patchset that Mike posted the > last time. Hopefully, the new patchset will be reviewed and merged. > I have ran and tested these patches for a long time, in my personal workstation (long story). I had no problems with them. Burn CDs and all. > With sg chaining, drain, padding, etc, building a scatterlist is much > complicated than in the past. I believe that we should kill home-made > scatterlist code and convert the users to use the block layer to avoid > potential scatterlist bugs. > -- Definitely, as I remember, Mike's code just prepares BIO's and requests and completely avoids any use of sg-lists. I will be waiting for your patches and will test them here. Thanks 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
