On Thursday 27 December 2007 13:09:27 FUJITA Tomonori wrote: > On Wed, 26 Dec 2007 11:27:40 +1100 > > Rusty Russell <[EMAIL PROTECTED]> wrote: > > There are many signs through the code that it needs a great deal of > > work: what is the purpose of sg_break? Why does the code check if > > kmap_atomic fails? > > sg_break is a workaround for the hardware restrictions, I think.
Well, scb->breakup does that, can't see what scb->sg_break is for... May have to wade through git history to understand it. > > === > > Convert the ips SCSI driver to sg_ring. > > > > Slightly non-trivial conversion, will need testing. > > As I said, I don't think that converting SCSI drivers to sg_ring (with > lots of non-trivial work) provides any benefits. Surely, sg_ring > enables us to modify sg lists but SCSI drivers don't need the > feature. What SCSI drivers needs is just a efficient way to get the > next sg entry (they use 'sg++' in the past and sg_next now). Sure, iteration over a two-level structure is a little more tricky, but it's pretty trivial for most drivers. Indeed, I think that it's probably better to have an explicitly different interface for sg_ring, and keep the current interface for small sg arrays. That would provide a nicer changeover. I'll prototype something and see what it's like... Rusty. - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
