Re: [RFC][PATCH] adding PCI bus information to SCSI layer

[Douglas Gilbert <dougg@torque.net>]

Alan Cox wrote:
> 
> > Also ISA adapters are not the only non-PCI adapters,
> > there are the growing band of pseudo adapters that
> > may or may not have a PCI bus at the bottom of some
> > other protocol stack.
> 
> An ioctl might be better. We already have an ioctl for querying the lun
> information for a disk. We could also return the bus information for its
> controller(s) [remember multipathing]

Both 'cat /proc/scsi/scsi' and ioctls used on
fds belonging to the existing upper level drivers
(e.g. sd and sr) have a problem as far as getting
HBA environment information: there needs to be at
least one SCSI device (target) connected to the
HBA. With no SCSI devices connected, there is no 
fd to do an ioctl on. [The same problem arises
if a device is there but marked offline, has an
exclusive lock on it, ...]

Perhaps Matt could look at the approach I have taken
with the scsimon experimental upper level driver.
Scsimon was originally designed to get scsi based
information to the /sbin/hotplug mechanism. It also
supplies ioctls to probe HBAs as well as SCSI devices.
More information about it can be found at:
  http://www.torque.net/scsi/scsimon.html

It should not be difficult to add HBA PCI bus information
to scsimon (after the Scsi_Host structure is expanded to
hold that information).

Doug Gilbert