Stefan Richter wrote: > Luben Tuikov wrote: > >> --- Jeff Garzik <jgarzik@xxxxxxxxx> wrote: >> >>> (HCIL should get marginalized, as all agree) > > > "Marginalized" was not the term that I remember. > >>> * Put HCIL mapping into top-level helper code, for sharing between FC >>> and SAS (hopefully!) >> >> >> One step further: eliminate the ugly legacy SPI-centric HCIL from >> SCSI Core. Minimise and streamline SCSI Core. > > > I agree. FC, SAS, USB, SBP et al do not need to _share_ some HCIL > mapping helpers --- they and the core need to get rid of HCIL mapping > entirely. Why spend energy on optimization of existing HCIL mappings? > > usb-storage and sbp2 already implement the leanest possible HCIL mapping > (1 logical unit to 1 H). Stefan, Here is a counter example from a USB multicard reader: $ lsscsi -v [0:0:0:0] disk Generic USB SD Reader 1.00 /dev/sda dir: /sys/bus/scsi/devices/0:0:0:0 [/sys/devices/pci0000:00/0000:00:07.2/usb1/1-1/1-1:1.0/host0/target0:0:0/0:0:0:0] [0:0:0:1] disk Generic USB CF Reader 1.01 /dev/sdb dir: /sys/bus/scsi/devices/0:0:0:1 [/sys/devices/pci0000:00/0000:00:07.2/usb1/1-1/1-1:1.0/host0/target0:0:0/0:0:0:1] [0:0:0:2] disk Generic USB SM Reader 1.02 /dev/sdc dir: /sys/bus/scsi/devices/0:0:0:2 [/sys/devices/pci0000:00/0000:00:07.2/usb1/1-1/1-1:1.0/host0/target0:0:0/0:0:0:2] [0:0:0:3] disk Generic USB MS Reader 1.03 /dev/sdd dir: /sys/bus/scsi/devices/0:0:0:3 [/sys/devices/pci0000:00/0000:00:07.2/usb1/1-1/1-1:1.0/host0/target0:0:0/0:0:0:3] That is 4 logical units to 1 host. [Since I'm often critical of USB mass storage device SCSI support, in this case it is good to see some thought went into the INQUIRY string namings.] There is an argument for the SCSI subsystem to keep at least the "l" part of the maligned <h:c:i:l> tuple because the "l" part really is SCSI (and should be u8[8]). SATA-II is beginning to struggle along that path as well with port multipliers of up to 15 devices. SCSI luns can easily cope with that. Doug Gilbert - : 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
