On 13-03-26 02:00 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)?
Chad,
Perhaps I'm missing something. Given a t10_LUN and linux32_LUN
and the proposed linux64_LUN then the traditional 16 bit LUN
value (flat space addressing ?) would be either:
(t10_LUN[0] << 8) | t10_LUN[1]
or
linux32_LUN & 0xffff
or
linux64_LUN & 0xffff
Doug Gilbert
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