Matthew Wilcox wrote:
Can you tell me a bit more about these drivers? Would it be possible to convert them to one host/many channels, which would give us the exclusion we want?
As a tangent, I would prefer a more "natural" representation than current, where there is a 1-1 correspondence between scsi_host and ATA controller instance, and a 1-1 correspondence between SCSI channels and ATA ports.
Alas _any_ change to the current setup requires special attention, because it is tied intimately into master/slave exclusion and scheduling.
I occasionally ponder what it would take to create an intelligent request scheduling framework that takes into account inflexible hardware bottlenecks like simplex (one command per controller, $n ports, $m devices), master/slave (one command port, $m devices), NCQ ($n commands per port, $m devices), port multipliers with their own bottlenecks, etc.
I see a lot of common code patterns in this area, but we are all sorta doing our own thing at a low level in drivers, because of subtle (and not-so-subtle) differences in hardware queueing support.
Jeff, thinking out loud - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
