Help - interface between Linux SCSI mid-level driver and lower-level driver

Help - interface between Linux SCSI mid-level driver and lower-level driver

[Lee Xing]

Hi,

I'm not SCSI driver expert.  Sorry for asking simple questions here.  Your help would be appreciated.

We are working on a new prototype that uses a FC HBA on Linux.  Our FC driver detects the physical FC disks as SCSI devices and reports them to a higher_layer (not Linux SCSI mid-level driver) in Linux kernel.  Now, we need to create another layer that sits in between the existing higher_layer and Linux SCSI mid-level driver, and to register the detected FC/SCSI devices as Linux sd/sg devices.

My question is what are the interface functions in SCSI mid-level driver we can invoke to register the detected FC/SCSI devices as Linux sg/sd devices.  Sample code and documents would be a great help.

Thanks,


L.

Re: Help - interface between Linux SCSI mid-level driver and lower-level driver

[Michael Pavlovsky]

Hi,
    I am working on something similar ( over InfiniBand)
I have no experiance with scsi subsystem and I am gothering any peace of
information about mid-core layer interface towards higher layers.
I hope next may help to you, and if you know more please publish it.
In order to activate mid layer you should call scsi_allocate_device 
after that
choose the right device from linked list and fill scsi_command struct
register it , and call scsi_do_command
I am going to write some code soon so I hope I would undertstand better.
For now the best source of information for me is 
http://www.andante.org/scsi.html
it is sucks ( just data structures and not complete)
and take unh-iscsi from sf.net they have scsi_target.{c,h} it is ~1500 
lines of code and readable

please write me if you know more.


Michael


Lee Xing wrote:

>Hi,
>
>I'm not SCSI driver expert.  Sorry for asking simple questions here.  Your help would be appreciated.
>
>We are working on a new prototype that uses a FC HBA on Linux.  Our FC driver detects the physical FC disks as SCSI devices and reports them to a higher_layer (not Linux SCSI mid-level driver) in Linux kernel.  Now, we need to create another layer that sits in between the existing higher_layer and Linux SCSI mid-level driver, and to register the detected FC/SCSI devices as Linux sd/sg devices.
>
>My question is what are the interface functions in SCSI mid-level driver we can invoke to register the detected FC/SCSI devices as Linux sg/sd devices.  Sample code and documents would be a great help.
>
>Thanks,
>
>
>L.
>
>-
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>  
>


-- 
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said in a hoarse growl, "the world would go round a 
deal faster than it does".

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 	Alice's Adventures in Wonderland, ch. 6 (1865).

Re: Help - interface between Linux SCSI mid-level driver and lower-level driver

[James Bottomley]

On Wed, 2004-03-24 at 15:12, Lee Xing wrote:
> My question is what are the interface functions in SCSI mid-level driver we can invoke to register the detected FC/SCSI devices as Linux sg/sd devices.  Sample code and documents would be a great help.

Documentation/scsi/scsi_mid_low_api.txt

Is a good starting point.

James