Re: [RFC]: 64 bit LUN/Tags, dummy device in host_queue, host_lock <-> LLDD reentrancy

James Bottomley
2002-08-26T21:10:24Z

andmike@us.ibm.com said:
> Ok, so we are looking for a sibling check

Exactly.

> Example tree
> devices/root/pci0/00:09.0/name "PCI device 1014:002e"
> devices/root/pci0/00:09.0/0/name "scsi0"
> devices/root/pci0/00:09.0/0/0/name "chan0"
> devices/root/pci0/00:09.0/0/0/1/name "tgt1"
> devices/root/pci0/00:09.0/0/0/1/1/name "lun1"
> devices/root/pci0/00:09.0/0/0/1/0/name "lun0"
> devices/root/pci0/00:09.0/0/0/0/name "tgt0"
> devices/root/pci0/00:09.0/0/0/0/1/name "lun1"
> devices/root/pci0/00:09.0/0/0/0/0/name "lun0"

I'm not too happy with this tree. The unique string
devices/root/pci0/00:09.0/name "PCI device 1014:002e" is enough to enumerate
the scsi card (as long as it's not multi-function). If I follow my PUN/LUN
position to its logical conclusion, we no longer need scsi host numbers,
either. tgt1 is really a fiction: For a device that has luns there's usually
no such thing as the target address (traditionally, it's LUN 0). However,
fundamentally, the point is that moving all this entirely into driverfs means
that scsi doesn't need to care what the tree looks like, it just has mappings
into parts of it.

James