Am 12/07/2012 07:58 PM, schrieb Mike Christie:
On 12/07/2012 08:51 AM, Hannes Reinecke wrote:
'Bus reset' is not really applicable to FibreChannel, as
the concept of a bus doesn't apply. Hence all FC LLDD
simulate a 'bus reset' by sending a target reset to each
attached remote port, causing error handling to spill
over to unaffected devices.
This patch implements a 'I_T nexus reset' handler,
which attempts to reset the I_T nexus to the remote
port. This way only the affected remote ports are
reset; other ports are left untouched.
Is the I_T nexus reset we are doing in this patch supposed to be the
same one defined in SAM? Was the I_T nexus reset TMF added to SAM at the
same time the target reset one was removed? In SAM 4 and 5 there is no
target reset anymore is there?
I think we should just kill the bus reset use from the FC drivers. Add a
new I_T nexus reset callout to the scsi_host_template or to the
scsi_transport_template. Then have scsi-ml call just either target reset
eh callout or I_T nexus eh reset callout depending on what the target
supports.
To figure out what the target supports could we do a REPORTED SUPPORTED
TASK MANAGEMENT FUNCTION command. If the target supports that command
and reports that the target supports the I_T nexus reset TMF then call
that eh callback, else drop down to older target reset eh callback.
It seems that if we do I_T nexus reset we do not need to also do a
target reset do we?
Hmm. I would rather check the actual LLDDs if they do anything sensible
for target reset.
If not we sure can remove it.
@@ -3266,8 +3271,8 @@ fc_timeout_fail_rport_io(struct work_struct *work)
if (rport->port_state != FC_PORTSTATE_BLOCKED)
return;
- rport->flags |= FC_RPORT_FAST_FAIL_TIMEDOUT;
fc_terminate_rport_io(rport);
+ rport->flags |= FC_RPORT_FAST_FAIL_TIMEDOUT;
}
What was the reason for moving this? For the eh case in this patch was
it causing IO to be failed with DID_TRANSPORT_FAILFAST when we wanted it
failed with some other error.
I wanted to ensure that fc_terminate_rport_io() was run when checking
FC_RPORT_FAST_FAIL_TIMEOUT.
Without the move there is a race window between clearing the flag and
calling fc_terminate_rport_io(), which one might trigger by just
checking the flag.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
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