Re: [Scst-devel] Discussion about SCST sysfs layout and implementation.

From: Kay Sievers
Date: Fri Apr 17 2009 - 10:25:26 EST


On Fri, Apr 17, 2009 at 15:25, Daniel Debonzi
<debonzi@xxxxxxxxxxxxxxxxxx> wrote:
> Vladislav Bolkhovitin wrote:

>>> Based on all I read this last days, I believe we are not allowed to
>>> include the directory scsi_tgt on /sys root. I think it has to be in a
>>> existent directory reserved for this sort of application. I just didn't
>>> figured out which one it would be.

Right, there will be no new out-of-/sys/devices/ top-level device dir,
unless you convince everybody to have a scsifs, which would be in
/sys/kernel/scsi/, and which would not use the driver core device
stuff at all. :)

>> /sys/class? It already has scsi_device, scsi_disk, scsi_generic and
>> scsi_host.

If it's a bus or a class, it does not matter. What you need to include
is a "struct device" (and not a kobject) if you want them to show up
in the common directories.

> I don't think so because all the directories on /sys/class have symlinks to
> the files somewhere else. However I noticed that many of them on my system
> are on /sys/device/virtual

All "struct device" devices appear in /sys/devices/, that's the single
place the hierarchy is expressed. The classification, meaning the
"collection of devices of the same subsystem" happens in /sys/bus/
/sys/class/, therefore they are only flat lists of links. Virtual are
devices which have no parent assigned. The driver core prepends
virtual to them, when they are registered.

Kay
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