On Fri, 2010-10-29 at 09:50 +0200, Andi Kleen wrote: > > I would have to agree that approach does make a bit more sense.. Now > > can some brave soul (/me looks at ak) code another script to automate > > this for the identified legacy LLDs cases that need push down..? > > For the drivers I looked at it doesn't really make too much difference, > I don't think there was any with a really large number of returns. > You can see that in the diffstat for the full changes. > Yep, this is a valid point. During the push down this week, I only ran into a handful (say ~15) overly-complex SHT->queuecommand() w more than a few return statements. This was also isoloated for the most part into legacy/ancient LLDs. > Writing another script is probably not too hard, but the problem > is that I needed a significant amount of manual post processing > (both the select the right files to patch and to get rid > of misplaced newlines and some mismatches in cocci) > So it's not a fully automated procedure. > <nod> So I really do not have a strong preference here. I think Boaz's approach is a bit cleaner, but in the end I think it should not hold up on a global push-down merge for lio-4.0.git/host_lock-less-for-37-v9. Also, at this point I have not received any other feedback from LLD maintainers to say "My LLD should be running in lock-less mode" or "My LLD cannot run in lock-less mode, and needs the host_lock push down". One additional point that was raised by jgarzik was that those LLDs running in 'lock-less' mode may need to have their internal ->queuecommand() spinlocks converted to spin_lock_irqsave() + spin_unlock_irqrestore(). This has already been fixed for libata following Jeff's recommendation, but we also identified a few other potential LLDs that may need more work. From the last response locatd here: http://marc.info/?l=linux-scsi&m=128825558912565&w=2 "Ok, so originally libiscsi, fnic, and lpfc where using spin_unlock(host->host_lock) -> spin_lock(host->host_lock) And libsas, qla2xxx, qla4xxx where using spin_unlock_irq(host->host_lock) -> spin_lock_irq(host->host_lock) Just to verify, you are thinking that those *not* using spin_unlock_irq + spin_lock_irq() for the legacy optimization dispatch should have their per LLD host lock converted to spin_lock_irqsave() + spin_unlock_irqrestore(), right..?" So I think that means an audit of locks obtained in libiscsi, fnic and lpfc will be in to ensure they do not assume irqs have alreadby been externally disabled for lock-less operation.. Any comments folks..? --nab -- 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
