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@redhat.com> --- 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@HansenPartnership.com> +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