On 06/11/2014 05:31 AM, Daniel P. Berrange wrote:
> On Tue, Jun 10, 2014 at 03:03:55PM -0400, John Ferlan wrote:
>> Add an optional unique_id parameter to nodedev. Allows for easier lookup
>> and display of the unique_id value in order to document for use with
>> scsi_host code.
>>
>> Signed-off-by: John Ferlan <jferlan@xxxxxxxxxx>
>> ---
>> docs/formatnode.html.in | 11 +++++++++++
>> docs/schemas/nodedev.rng | 6 ++++++
>> src/conf/node_device_conf.c | 23 ++++++++++++++++------
>> src/conf/node_device_conf.h | 1 +
>> src/node_device/node_device_linux_sysfs.c | 6 ++++++
>> src/test/test_driver.c | 5 +++--
>> .../pci_8086_27c5_scsi_host_0_unique_id.xml | 8 ++++++++
>> tests/nodedevxml2xmltest.c | 1 +
>> 8 files changed, 53 insertions(+), 8 deletions(-)
>> create mode 100644 tests/nodedevschemadata/pci_8086_27c5_scsi_host_0_unique_id.xml
>>
>> diff --git a/docs/formatnode.html.in b/docs/formatnode.html.in
>> index 76bf8af..cdf0277 100644
>> --- a/docs/formatnode.html.in
>> +++ b/docs/formatnode.html.in
>> @@ -173,6 +173,17 @@
>> <dl>
>> <dt><code>host</code></dt>
>> <dd>The SCSI host number.</dd>
>> + <dt><code>unique_id</code></dt>
>> + <dd>On input, this optionally provides the value from the
>> + 'unique_id' file found in the scsi_host's directory. To
>> + view the values of all 'unique_id' files, use <code>find -H
>> + /sys/class/scsi_host/host{0..9}/unique_id |
>> + xargs grep '[0-9]'</code>. On output, if the unique_id
>> + file exists, the value from the file will be displayed.
>> + This can be used in order to help uniquely identify the
>> + scsi_host adapter in a <a href="formatstorage.html">
>> + Storage Pool</a>. <span class="since">Since 1.2.6</span>
>> + </dd>
>
> Where is the data from the 'unique_id' coming from ? Is this since that
> Linux makes up, or is it some standard attribute from the hardware ? It
> would be desirable to document what it is in a way that's not simply
> refering to Linux sysfs, since sysfs itself is mostly undocumented :-)
>
>
Using 'unique_id' was from Osier's initial design - I 'assumed' that his
research into this had determined using this was unique enough.
A small amount of searching turns this up:
https://lkml.org/lkml/2011/8/17/274
...
+What: /sys/bus/scsi/devices/host*/scsi_host/host*/unique_id
+Date: February, 2003
+KernelVersion: Unknown
+Contact: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
+Description:
+ Read only unsigned integer uniquely identifying the SCSI host
+ within the system. This value is assigned by the low level
+ driver.
+
...
Also from various sources, there's '/linux/include/scsi/scsi_host.h
/*
* This is a unique identifier that must be assigned so that we
* have some way of identifying each detected host adapter properly
* and uniquely. For hosts that do not support more than one card
* in the system at one time, this does not need to be set. It is
* initialized to 0 in scsi_register.
*/
unsigned int unique_id;
> Regards,
> Daniel
>
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