Re: [PATCH 1/2] scsi error: add target reset eh handler

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Tue, 2007-12-18 at 22:11 -0600, michaelc@cs.wisc.edu wrote:
> From: Mike Christie <michaelc@cs.wisc.edu>
> 
> Drivers like qla4xxx and bnx2i (and it looks like some fcp drivers too),
> want to be able to send a lun reset in the eh device handler and then a
> target reset in some other handler. The old linux-iscsi driver, which did
> the host per session like open-iscsi did the target reset in the host reset,
> because the scsi command accounting that scsi_error.c does worked out
> nicely for software iscsi, but does not work for hardware iscsi well.
> 
> This patch adds a eh_target_reset_handler any driver can use to send
> a target reset.
> 
> The next patch will hook qla4xxx into it, and patches for iscsi_tcp/iser
> and bnx2i will follow later when bnx2i is closer to getting merged.

We sort of have a mapping problem here.  In the old ways of the error
handler, since it was based on SPI and SCSI-2, when it said "device
reset" what it actually meant was target reset, since that was the only
message the SPI bus could send.  It was only in the later SCSI-3
standard that a LUN reset came along.  So, most resent implementations
(even FC ones) send a target reset for this function.

So ... where I'm going is that I'm not averse to adding a target reset
(it has been suggested before), but then we'll have to clean up a lot of
other drivers.  Alternatively, you could just plumb target reset in to
the qla2xxx where device reset now is.

What do people think?

James