On 03/27/2013 08:37 AM, Hannes Reinecke wrote: > On 03/26/2013 07:00 PM, Chad Dupuis wrote: >> >> >> On Tue, 19 Feb 2013, Hannes Reinecke wrote: >> >>> This patchset updates the SCSI midlayer to use 64-bit LUNs >>> internally. >>> It eliminates the need to limit the number of LUNs artificially to >>> avoid aliasing issues; the SCSI midlayer can now accept any LUN >>> presented >>> to it. >>> >>> The LLDD specific settings for 'max_lun' have been left untouched; >>> it should be raised to '~0' if the HBA supports 64-bit LUNs >>> internally. >>> However, it is up to the driver maintainer to raise that limit. >>> >>> Hannes Reinecke (4): >>> scsi_scan: Fixup scsilun_to_int() >>> scsi: use 64-bit LUNs >>> scsi: use 64-bit value for 'max_luns' >>> scsi: Remove CONFIG_SCSI_MULTI_LUN >>> >> >> Hannes, >> >> As we've reviewed these patches internally, the one question that keeps >> coming up is how do we handle hardware that cannot handle a 64-bit LUN >> address? For example, some of our older 2G/bps hardware can only >> handle a 16-bit LUN address. Currently we convert the u32 value to u16. > > Do we do the same for the 64-bit conversion? Can a way be > devised to >> "opt-out" of receiving a 64-bit address in the first place (IIRC this > > was an option in the v1 patch set)? >> > Yes, you can. > > The idea here is to let 'max_luns' control this behaviour; > 'max_luns' is the highest LUN number the host can support. > So for 16-bit LUN you would set max_luns to '0xFFFF', and for 32-bit > LUN addresses you would be setting max_luns to '0xFFFFFFFF'. Hi all, in scsi_report_lun_scan is max_lun compared with the result of scsilun_to_int, but in that value is also stored the address method. This means, that we compare the max_lun to a LUN 'handle' which doesn't seem to make much sense. This makes that test dependent on which address method is used and not only to the LUN number which is I think expected. The solution is to have a new function 'scsilun_to_num', (I can send a patch) or let the individual drivers set the max_lun to -1 and test for the allowed LUNs in the driver. Thanks, Tomas > > However, since you mention it, maybe I should add a 'scsilun_to_u32' > conversion routine, as this is requested in several places. > > Cheers, > > Hannes -- 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
