From: Dan Williams <dan.j.williams@intel.com>
To: Greg KH <greg@kroah.com>,
James Bottomley <James.Bottomley@suse.de>,
Kay Sievers <kay.sievers@vrfy.org>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"Nadolski, Edmund" <edmund.nadolski@intel.com>,
"Jiang, Dave" <dave.jiang@intel.com>,
"Skirvin, Jeffrey D" <jeffrey.d.skirvin@intel.com>,
"Danecki, Jacek" <jacek.danecki@intel.com>
Subject: Should isci create its own device class?
Date: Tue, 01 Mar 2011 19:22:39 -0800 [thread overview]
Message-ID: <4D6DB7FF.4090506@intel.com> (raw)
For compatibility with other software raid environments an isci [1]
device may contain up to two controller instances per pci device.
Currently the sysfs path for its scsi_host objects is:
> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/0000:02:08.0/0000:03:00.0/host10/scsi_host/host10
> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/0000:02:08.0/0000:03:00.0/host11/scsi_host/host11
But to reflect reality the pci device is actually the parent of two
independent controller instances. With a mockup like:
> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/0000:02:08.0/0000:03:00.0/controller0/host10/scsi_host/host10
> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/0000:02:08.0/0000:03:00.0/controller1/host11/scsi_host/host11
I can see this being beneficial in a few ways:
1/ fix dev_printk() messages which right now give an ambiguous "isci
0000:03:00.0" prefix
2/ controller boundaries are visible via the sysfs path without need to
to look at sas_addresses to determine the controller.
2/ if we ever wanted to support some per controller attributes between
the global pci attributes and the scsi_host attributes.
...but would this confuse /dev/disk/by-path/ or any other unintended
side effects?
--
Dan
[1]: http://marc.info/?l=linux-scsi&m=129703780424729&w=2
next reply other threads:[~2011-03-02 3:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-02 3:22 Dan Williams [this message]
2011-03-02 12:49 ` Should isci create its own device class? James Bottomley
2011-03-02 18:38 ` Dan Williams
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