linux-toradex.git/include/scsi/sas_ata.h, branch v3.4.3

[SCSI] libsas, libata: fix start of life for a sas ata_port

2012-04-23T11:11:47+00:00

This changes the ordering of initialization and probing events from:
  1/ allocate rphy in PORTE_BYTES_DMAED, DISCE_REVALIDATE_DOMAIN
  2/ allocate ata_port and schedule port probe in DISCE_PROBE
...to:
  1/ allocate ata_port in PORTE_BYTES_DMAED, DISCE_REVALIDATE_DOMAIN
  2/ allocate rphy in PORTE_BYTES_DMAED, DISCE_REVALIDATE_DOMAIN
  3/ schedule port probe in DISCE_PROBE

This ordering prevents PHYE_SIGNAL_LOSS_EVENTS from sneaking in to
destrory ata devices before they have been fully initialized:

  BUG: unable to handle kernel paging request at 0000000000003b10
  IP: [] sas_ata_end_eh+0x12/0x5e [libsas]
  ...
  [] sas_unregister_common_dev+0x78/0xc9 [libsas]
  [] sas_unregister_dev+0x4f/0xad [libsas]
  [] sas_unregister_domain_devices+0x7f/0xbf [libsas]
  [] sas_deform_port+0x61/0x1b8 [libsas]
  [] sas_phye_loss_of_signal+0x29/0x2b [libsas]

...and kills the awkward "sata domain_device briefly existing in the
domain without an ata_port" state.

Reported-by: Michal Kosciowski 
Signed-off-by: Dan Williams 
Acked-by: Jeff Garzik 
Signed-off-by: James Bottomley

[SCSI] libsas: async ata scanning

2012-02-29T21:35:41+00:00

libsas ata error handling is already async but this does not help the
scan case.  Move initial link recovery out from under host->scan_mutex,
and delay synchronization with eh until after all port probe/recovery
work has been queued.

Device ordering is maintained with scan order by still calling
sas_rphy_add() in order of domain discovery.

Since we now scan the domain list when invoking libata-eh we need to be
careful to check for fully initialized ata ports.

Acked-by: Jack Wang 
Acked-by: Jeff Garzik 
Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley

[SCSI] libsas: restore scan order

2012-02-29T21:34:19+00:00

ata devices are always scanned after ssp.  Prior to the ata error
handling reworks libsas would tend to scan devices in ascending expander
phy order.  Restore this ordering by deferring ssp discovery to a
DISCE_PROBE event, and keep the probe order consistent with the
discovery order, not the placement of sata devices.

Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley

[SCSI] libsas: let libata recover links that fail to transmit initial sig-fis

2012-02-29T21:33:02+00:00

libsas fails to discover all sata devices in the domain.  If a device fails
negotiation and does not transmit a signature fis the link needs recovery.
libata already understands how to manage slow to come up links, so treat these
conditions as ata device attach events for the purposes of creating an
ata_port.  This allows libata to manage retrying link bring up.

Rediscovery is modified to be careful about checking changes in dev_type.  It
looks like libsas leaks old devices if the sas address changes, but that's a
fix for another patch.

Acked-by: Jack Wang 
Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley

[SCSI] libsas: fix mixed topology recovery

2012-02-29T21:23:24+00:00

If we have a domain with sas and sata devices there may still be sas
recovery actions to take after peeling off the commands to send to
libata.

Reported-by: Andrzej Jakowski 
Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley

[SCSI] libsas: execute transport link resets with libata-eh via host workqueue

2012-02-19T20:13:51+00:00

Link resets leave ata affiliations intact, so arrange for libsas to make
an effort to avoid dropping the device due to a slow-to-recover link.
Towards this end carry out reset in the host workqueue so that it can
check for ata devices and kick the reset request to libata.  Hard
resets, in contrast, bypass libata since they are meant for associating
an ata device with another initiator in the domain (tears down
affiliations).

Need to add a new transport_sas_phy_reset() since the current
sas_phy_reset() is a utility function to libsas lldds.  They are not
prepared for it to loop back into eh.

Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley

[SCSI] libsas: use libata-eh-reset for sata rediscovery fis transmit failures

2012-02-19T20:09:32+00:00

Since sata devices can take several seconds to recover the link on reset
the 0.5 seconds that libsas currently waits may not be enough.  Instead
if we are rediscovering a phy that was previously attached to a sata
device let libata handle any resets to encourage the device to transmit
the initial fis.

Once sas_ata_hard_reset() and lldds learn how to honor 'deadline' libsas
should stop encountering phys in an intermediate state, until then this
will loop until the fis is transmitted or ->attached_sas_addr gets
cleared, but in the more likely initial discovery case we keep existing
behavior.

Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley

[SCSI] libsas: fix timeout vs completion race

2012-02-19T20:06:08+00:00

Until we have told the lldd to forget a task a timed out operation can
return from the hardware at any time.  Since completion frees the task
we need to make sure that no tasks run their normal completion handler
once eh has decided to manage the task.  Similar to
ata_scsi_cmd_error_handler() freeze completions to let eh judge the
outcome of the race.

Task collector mode is problematic because it presents a situation where
a task can be timed out and aborted before the lldd has even seen it.
For this case we need to guarantee that a task that an lldd has been
told to forget does not get queued after the lldd says "never seen it".
With sas_scsi_timed_out we achieve this with the ->task_queue_flush
mutex, rather than adding more time.

Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley

[SCSI] libsas: prevent domain rediscovery competing with ata error handling

2012-02-19T19:52:34+00:00

libata error handling provides for a timeout for link recovery.  libsas
must not rescan for previously known devices in this interval otherwise
it may remove a device that is simply waiting for its link to recover.
Let libata-eh make the determination of when the link is stable and
prevent libsas (host workqueue) from taking action while this
determination is pending.

Using a mutex (ha->disco_mutex) to flush and disable revalidation while
eh is running requires any discovery action that may block on eh be
moved to its own context outside the lock.  Probing ATA devices
explicitly waits on ata-eh and the cache-flush-io issued during device
removal may also pend awaiting eh completion.  Essentially any rphy
add/remove activity needs to run outside the lock.

This adds two new cleanup states for sas_unregister_domain_devices()
'allocated-but-not-probed', and 'flagged-for-destruction'.  In the
'allocated-but-not-probed' state  dev->rphy points to a rphy that is
known to have not been through a sas_rphy_add() event.  At domain
teardown check if this device is still pending probe and cleanup
accordingly.  Similarly if a device has already been queued for removal
then sas_unregister_domain_devices has nothing to do.

Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley

[SCSI] libsas: fix leak of dev->sata_dev.identify_[packet_]device

2012-02-19T19:39:36+00:00

These are never freed in the nominal path.  A domain_device has a
different lifetime than a sas_rphy we need a dev->rphy independent way
of identifying sata devices.

Reviewed-by: Jack Wang 
Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley