On 02/05/2016 09:26 AM, Himanshu Madhani wrote:
On 2/4/16, 10:16 AM, "Bart Van Assche" <bart.vanassche@xxxxxxxxxxx> wrote:
On 02/04/2016 08:45 AM, Himanshu Madhani wrote:
From: Quinn Tran <quinn.tran@xxxxxxxxxx>
#cat /sys/kernel/debug/qla2xxx/qla2xxx_31/tgt_sess
qla2xxx_31
Port ID Port Name Handle
ff:fc:01 21:fd:00:05:33:c7:ec:16 0
01:0e:00 21:00:00:24:ff:7b:8a:e4 1
01:0f:00 21:00:00:24:ff:7b:8a:e5 2
....
Hello Quinn and Himanshu,
The above information is not only useful to people who are debugging the
QLogic target driver but also to end users who want to check which
initiator ports have already logged in to a target port. Hence my
proposal to move this information from debugfs to another location (e.g.
configfs or sysfs). Users of other target drivers are probably also
interested in seeing which sessions are active. How about adding the
functionality for reporting session information per target port in the
LIO core in such a way that some attributes are available for all target
drivers (e.g. initiator port name, SCSI command statistics) and such
that target drivers can define additional attributes to exported for
each session (e.g. port ID, handle, ...).
We had initially implemented this as a sysfs hook, but knowing that sysfs
is not encouraged, we decided to put this information via debugfs. Would it
make more sense if we send a sysfs patch?
Hello Himanshu,
Let's try to reach agreement about the approach first before starting to
rework this patch.
Five years ago I explained in a message that I posted on the linux-scsi
mailing list why LIO should use sysfs to export information that changes
dynamically (see also http://thread.gmane.org/gmane.linux.scsi/65615/).
I think this patch shows that there is a real need to have detailed
session information from LIO target drivers in user space. We need one
directory per session instead of exporting all session information
through a single file. sysfs is the right filesystem to export such
information because configfs directories should be created by the user
and not from inside the kernel. If no agreement can be reached about
this over e-mail my proposal is to discuss this further at the 2016
LSF/MM summit.
Thanks,
Bart.
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