linux-toradex.git/drivers/message, branch v2.6.27.62

mptsas: fix hangs caused by ATA pass-through

2011-04-30T14:53:40+00:00

commit 2a1b7e575b80ceb19ea50bfa86ce0053ea57181d upstream.

I may have an explanation for the LSI 1068 HBA hangs provoked by ATA
pass-through commands, in particular by smartctl.

First, my version of the symptoms.  On an LSI SAS1068E B3 HBA running
01.29.00.00 firmware, with SATA disks, and with smartd running, I'm seeing
occasional task, bus, and host resets, some of which lead to hard faults of
the HBA requiring a reboot.  Abusively looping the smartctl command,

    # while true; do smartctl -a /dev/sdb > /dev/null; done

dramatically increases the frequency of these failures to nearly one per
minute.  A high IO load through the HBA while looping smartctl seems to
improve the chance of a full scsi host reset or a non-recoverable hang.

I reduced what smartctl was doing down to a simple test case which
causes the hang with a single IO when pointed at the sd interface.  See
the code at the bottom of this e-mail.  It uses an SG_IO ioctl to issue
a single pass-through ATA identify device command.  If the buffer
userspace gives for the read data has certain alignments, the task is
issued to the HBA but the HBA fails to respond.  If run against the sg
interface, neither the test code nor smartctl causes a hang.

sd and sg handle the SG_IO ioctl slightly differently.  Unless you
specifically set a flag to do direct IO, sg passes a buffer of its own,
which is page-aligned, to the block layer and later copies the result
into the userspace buffer regardless of its alignment.  sd, on the other
hand, always does direct IO unless the userspace buffer fails an
alignment test at block/blk-map.c line 57, in which case a page-aligned
buffer is created and used for the transfer.

The alignment test currently checks for word-alignment, the default
setup by scsi_lib.c; therefore, userspace buffers of almost any
alignment are given directly to the HBA as DMA targets.  The LSI 1068
hardware doesn't seem to like at least a couple of the alignments which
cross a page boundary (see the test code below).  Curiously, many
page-boundary-crossing alignments do work just fine.

So, either the hardware has an bug handling certain alignments or the
hardware has a stricter alignment requirement than the driver is
advertising.  If stricter alignment is required, then in no case should
misaligned buffers from userspace be allowed through without being
bounced or at least causing an error to be returned.

It seems the mptsas driver could use blk_queue_dma_alignment() to advertise
a stricter alignment requirement.  If it does, sd does the right thing and
bounces misaligned buffers (see block/blk-map.c line 57).  The following
patch to 2.6.34-rc5 makes my symptoms go away.  I'm sure this is the wrong
place for this code, but it gets my idea across.

Acked-by: "Desai Kashyap" 
Signed-off-by: James Bottomley

Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6

2008-07-27T17:04:52+00:00

* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (59 commits)
  [SCSI] replace __FUNCTION__ with __func__
  [SCSI] extend the last_sector_bug flag to cover more sectors
  [SCSI] qla2xxx: Update version number to 8.02.01-k6.
  [SCSI] qla2xxx: Additional NPIV corrections.
  [SCSI] qla2xxx: suppress uninitialized-var warning
  [SCSI] qla2xxx: use memory_read_from_buffer()
  [SCSI] qla2xxx: Issue proper ISP callbacks during stop-firmware.
  [SCSI] ch: fix ch_remove oops
  [SCSI] 3w-9xxx: add MSI support and misc fixes
  [SCSI] scsi_lib: use blk_rq_tagged in scsi_request_fn
  [SCSI] ibmvfc: Update driver version to 1.0.1
  [SCSI] ibmvfc: Add ADISC support
  [SCSI] ibmvfc: Miscellaneous fixes
  [SCSI] ibmvfc: Fix hang on module removal
  [SCSI] ibmvfc: Target refcounting fixes
  [SCSI] ibmvfc: Reduce unnecessary log noise
  [SCSI] sym53c8xx: free luntbl in sym_hcb_free
  [SCSI] scsi_scan.c: Release mutex in error handling code
  [SCSI] scsi_eh_prep_cmnd should save scmd->underflow
  [SCSI] sd: Support for SCSI disk (SBC) Data Integrity Field
  ...

[SCSI] replace FUNCTION with func

2008-07-27T14:31:49+00:00

[jejb: fixed up a ton of missed conversions.

 All of you are on notice this has happened, driver trees will now
 need to be rebased]

Signed-off-by: Harvey Harrison 
Cc: SCSI List 
Signed-off-by: Andrew Morton 
Signed-off-by: James Bottomley

Documentation cleanup: trivial misspelling, punctuation, and grammar corrections.

2008-07-26T19:00:06+00:00

Cc: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

I2O: handle sysfs_create_link() failures

2008-07-24T17:47:30+00:00

Compile warning:
ignoring return value of `sysfs_create_link', declared with attribute warn_unused_result.

If sysfs_create_link failed, take care of the return value and do some
error handle after the failure.

Since sysfs_remove_link() will check whether a link exists, when removing the
link in error path, we don't need to care whether a link was created.

Signed-off-by: Wang Chen 
Cc: Markus Lidel 
Cc: Jens Axboe 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

driver core: remove KOBJ_NAME_LEN define

2008-07-22T04:54:52+00:00

Kobjects do not have a limit in name size since a while, so stop
pretending that they do.

Signed-off-by: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6

2008-07-16T01:58:04+00:00

* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (102 commits)
  [SCSI] scsi_dh: fix kconfig related build errors
  [SCSI] sym53c8xx: Fix bogus sym_que_entry re-implementation of container_of
  [SCSI] scsi_cmnd.h: remove double inclusion of linux/blkdev.h
  [SCSI] make struct scsi_{host,target}_type static
  [SCSI] fix locking in host use of blk_plug_device()
  [SCSI] zfcp: Cleanup external header file
  [SCSI] zfcp: Cleanup code in zfcp_erp.c
  [SCSI] zfcp: zfcp_fsf cleanup.
  [SCSI] zfcp: consolidate sysfs things into one file.
  [SCSI] zfcp: Cleanup of code in zfcp_aux.c
  [SCSI] zfcp: Cleanup of code in zfcp_scsi.c
  [SCSI] zfcp: Move status accessors from zfcp to SCSI include file.
  [SCSI] zfcp: Small QDIO cleanups
  [SCSI] zfcp: Adapter reopen for large number of unsolicited status
  [SCSI] zfcp: Fix error checking for ELS ADISC requests
  [SCSI] zfcp: wait until adapter is finished with ERP during auto-port
  [SCSI] ibmvfc: IBM Power Virtual Fibre Channel Adapter Client Driver
  [SCSI] sg: Add target reset support
  [SCSI] lib: Add support for the T10 (SCSI) Data Integrity Field CRC
  [SCSI] sd: Move scsi_disk() accessor function to sd.h
  ...

Merge commit 'v2.6.26' into bkl-removal

2008-07-14T21:29:34+00:00

[SCSI] mpt fusion : Adding FAULT Reset polling work

2008-07-12T13:22:15+00:00

When the firmware is in Fault state it will be identifed only when the next time
the driver access the IOC state.
This patch includes a polling function in the driver which will be executed in
regular interval to check the status of the firmware and if it is in Fault
state, then the firmware will be reset by the driver.

Signed-off-by: Sathya Prakash 
Signed-off-by: James Bottomley

[SCSI] mpt fusion : Setting intial period to 0xFF instead of 0xA

2008-07-12T13:22:14+00:00

The initial period is set to 0xFF

Signed-off-by: Sathya Prakash 
Signed-off-by: James Bottomley