final SCSI fixes for 2.6.15-rc5

"Current Issues with 2.6.15-rc5" sent today:

Hello Everyone,

I'm concerned about the stability of the fibre channel infrastructure in 2.6.15-rc. There are current issues which I see effecting our (SGI's) customers' satisfaction. I feel that these issues must be addressed prior to the release of 2.6.15.

1 - fc transport change gets really noisy if targets disappear from
the fabric due to recursion on the workqueue. I've seen recursion depths > 40 and it's only really limited by the number of targets on a fibre channel fabric. It's unknown (to me) what side effects this recursion might have if the number of targets is in the hundreds, which is not uncommon for our customers. James Smart is aware of this and is working on a solution.
See my posting of 12/2/2005 and replies.
"2.6.15-rc4 error messages with multiple qla2300 hba ports on fabric".

2 - qlogic fibre channel driver no longer properly handles targets coming
and going. There is a race condition within the driver which can result in targets being deleted yet they are present and accounted for. This is a show stopper for SGI's customers. We have to have reliable target [re-]discovery. Andrew Vasquez is aware of this issue. See my posting on 12/5/2005. "qla2x00 driver serialization issue".

Quoted 5 lines · Andrew

Quoted 5 lines

Yes, I was afraid of something like this happening (due to qla2xxx detections of ports being dropped from an interrupt context)... Codes in qla_rscn.c already queue-up rport_adds() via the standard kernel-workqueue:

Quoted 7 lines

Quoted 7 lines

	qla_init.c:     INIT_WORK(&fcport->rport_add_work, qla2x00_rport_add, fcport);

	qla_rscn.c:     schedule_work(&fcport->rport_add_work);

With the additions though, I'm wondering if adding a special single-cpu qla2xxx-rport workqueue would make sense (at least we could enforce serialization).

What can be done to assure fc stability in the 2.6.15 release? It appears that the revision of the fc-transport from 2.6.14 has caused some difficulty for a current driver, and potentially the entire system. Is it ready for prime time?

Mike Reed

These should (hopefully) represent the last few urgent bug fixes that have shown up. The fixes are available here:

master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6.git

The short changelog is:

Andrew Vasquez:
o qla2xxx: Correct short-WRITE status handling
o qla2xxx: Correct mis-handling of AENs

Brian King:
o fix double free of scsi request queue

Dave Boutcher:
o ibmvscsi kexec fix

James Bottomley:
o Consolidate REQ_BLOCK_PC handling path (fix ipod panic)

Jens Axboe:
o fix panic when ejecting ieee1394 ipod

Mark Lord:
o Fix incorrect pointer in megaraid.c MODE_SENSE emulation

Matthew Wilcox:
o Negotiate correctly with async-only devices

Michael Reed:
o fix OOPS due to clearing eh_action prior to aborting eh command

And the diffstat:

 drivers/scsi/ibmvscsi/ibmvscsi.h      |    2 +-
 drivers/scsi/ibmvscsi/iseries_vscsi.c |    3 ++-
 drivers/scsi/ibmvscsi/rpa_vscsi.c     |    8 +++++++-
 drivers/scsi/megaraid.c               |    2 +-
 drivers/scsi/qla2xxx/qla_def.h        |   10 +---------
 drivers/scsi/qla2xxx/qla_init.c       |    6 +++---
 drivers/scsi/qla2xxx/qla_isr.c        |   15 +++++++++++++++
 drivers/scsi/scsi_error.c             |    7 ++++++-
 drivers/scsi/scsi_lib.c               |   33 +++++++++++++++++++++------------
 drivers/scsi/scsi_scan.c              |    1 -
 drivers/scsi/sd.c                     |   16 +---------------
 drivers/scsi/sr.c                     |   20 +++-----------------
 drivers/scsi/st.c                     |   19 +------------------
 drivers/scsi/sym53c8xx_2/sym_hipd.c   |    4 ++--
 include/scsi/scsi_cmnd.h              |    1 +
 15 files changed, 65 insertions(+), 82 deletions(-)

James

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If possible, a comment on my previous email which identified two other issues with SCSI would be appreciated before 2.6.15 goes final.

These should (hopefully) represent the last few urgent bug fixes that have shown up. The fixes are available here:

master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6.git