Luben Tuikov wrote:
On 08/26/05 15:24, Jeff Garzik wrote:
Luben Tuikov wrote:
Even simpler: the transport layer, calls SCSI Core, saying: "Hey here is
a pointer to struct scsi_domain_device. If you want, you an send REPORT
LUNS and other things to it."
For the SG_IO ioctl, /dev/sg and request_queue usage, SCSI core must map
an address (currently HCIL) into a scsi_domain_device pointer. These
The request queue is associated with the LU, not the scsi_domain_device.
When SCSI Core discovers the LU, it sets up the request queue for it,
etc. Again this is the role of SCSI Core, not messing up with transport
specific stuff.
upper layer kernel elements rely on this "SCSI address", and rely on the
fact that SCSI core can route from a block device straight to a SCSI
LLD, using nothing more than this "SCSI address."
I don't get this.
More basically... An in-kernel C pointer, to a SCSI target device, is
not sufficient in all cases to address a target. This plays out most
often in userland interfaces such as ioctls.
That is the heart of the routing/addressing that the SCSI core must perform.
Disagree: now: scsi_device <--> request_queue, then: struct LU <-->
request_queue.
The LU points to the domain_device (as its parent). The domain_device
has a void *lldd_dev in it.
The current SCSI code largely already has this stuff.
Right now the addressing is hardcoded to HCIL. But that can be
changed... One proposal was to use (host,string) identifiers.
Who? Who is proposing this? I never saw an email to SCSI Core about
this proposal? Is there any more information about this proposal
and what is the justification of it? Any specs and docs?
No specs, just a comment from IRC.
(host,string) could succeed in transporting both HCIL and non-HCIL
target identifiers.
Jeff
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