linux-toradex.git/drivers/scsi/isci/task.h, branch v3.12-rc2

isci: Redesign device suspension, abort, cleanup.

2012-05-17T21:33:38+00:00

This commit changes the means by which outstanding I/Os are handled
for cleanup.
The likelihood is that this commit will be broken into smaller pieces,
however that will be a later revision.  Among the changes:

- All completion structures have been removed from the tmf and
abort paths.
- Now using one completed I/O list, with the I/O completed in host bit being
used to select error or normal callback paths.

Signed-off-by: Jeff Skirvin 
Signed-off-by: Dan Williams

[SCSI] isci: remove bus and reset handlers

2012-02-29T21:16:05+00:00

Remove ->eh_device_reset_handler() and ->eh_bus_reset_handler() for the
same reason they are not implemented for libata hosts, they cannot be
implemented reliably with ata-eh.  ATA error recovery wants to divert
all resets to the eh thread and wait for completion, these handlers may
be invoked from a non-blocking ioctl.

The other path they are called from is libsas-eh, and if we escalate
past I_T_nexus reset we have larger problems i.e. tear down all
in-flight commands in the domain potentially without notification to the
lldd if it has chosen not to implement ->lldd_clear_nexus_port() /
->lldd_clear_nexus_ha().

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

[SCSI] isci: stop interpreting ->lldd_lu_reset() as an ata soft-reset

2012-02-29T21:13:40+00:00

Driving resets from libsas-eh is pre-mature as libata will make a
decision about performing a softreset.  Currently libata determines
whether to perform a softreset based on ata_eh_followup_srst_needed(),
and none of those conditions apply to isci.

Remove the srst implementation and translate ->lldd_lu_reset() for ata
devices as a request to drive a reset via libata-eh.

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

[SCSI] libsas: remove ata_port.lock management duties from lldds

2012-02-19T19:50:12+00:00

Each libsas driver (mvsas, pm8001, and isci) has invented a different
method for managing the ap->lock.  The lock is held by the ata
->queuecommand() path.  mvsas drops it prior to acquiring any internal
locks which allows it to hold its internal lock across calls to
task->task_done().  This capability is important as it is the only way
the driver can flush task->task_done() instances to guarantee that it no
longer has any in-flight references to a domain_device at
->lldd_dev_gone() time.

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

[SCSI] isci: remove unused 'isci_tmf->device' field

2012-01-16T07:44:15+00:00

As the field was never set, isci_print_tmf() using 'isci_tmf->device'
sometimes causes a kernel crash if the dev_dbg() statement is enabled.
Remove the unused field both from isci_tmf struct definition and from
isci_print_tmf()

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

[SCSI] isci: Fix task management for SMP, SATA and on dev remove.

2011-10-31T09:17:48+00:00

libsas uses the LLDD abort task interface to handle I/O timeouts
in the SATA/STP and SMP discovery paths, so this change will terminate
STP/SMP requests. Also, if the device is gone, the lldd will prevent
libsas from further escalations in the error handler.

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

[SCSI] isci: Handle task request timeouts correctly.

2011-10-31T09:16:23+00:00

In the case where "task" requests timeout (note that this class of
requests can also include SATA/STP soft reset FIS transmissions),
handle the case where the task was being managed by some call to
terminate the task request by completing both the tmf and the aborting
process.

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

[SCSI] isci: SATA/STP I/O is only returned in the normal path to libsas

2011-10-02T18:21:24+00:00

Since libsas has it's own means to escalate SATA/STP device error
handling depending on task status codes, return all SATA/STP I/O
on the normal path.

i.e. skip sas_task_abort() and let sas_ata_task_done() disposition the
qc.  Longer term we want to audit non-essential calls to
sas_task_abort().

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

isci: merge sata.[ch] into request.c

2011-07-03T11:04:52+00:00

Undo some needless separation.

Signed-off-by: Dan Williams

isci: atomic device lookup and reference counting

2011-07-03T11:04:51+00:00

We have unsafe references to remote devices that are notified to
disappear at lldd_dev_gone.  In order to clean this up we need a single
canonical source for device lookups and stable references once a lookup
succeeds.  Towards that end guarantee that domain_device.lldd_dev is
NULL as soon as we start the process of stopping a device.  Any code
path that wants to safely lookup a remote device must do so through
task->dev->lldd_dev (isci_lookup_device()).

For in-flight references outside of scic_lock we need reference counting
to ensure that the device is not recycled before we are done with it.
Simplify device back references to just scic_sds_request.target_device
which is now the only permissible internal reference that is maintained
relative to the reference count.

There were two occasions where we wanted new i/o's to be treated as
SAS_TASK_UNDELIVERED but where the domain_dev->lldd_dev link is still
intact.  Introduce a 'gone' flag to prevent i/o while waiting for libsas
to take action on the port down event.

One 'core' leftover is that we currently call
scic_remote_device_destruct() from isci_remote_device_deconstruct()
which is called when the 'core' says the device is stopped.  It would be
more natural for the final put to trigger
isci_remote_device_deconstruct() but this implementation is deferred as
it requires other changes.

Signed-off-by: Dan Williams