There is a possble racing scenario.
'process_oq' is called by two routines, as shown below.
pm8001_8001_dispatch = {
.......
.isr = pm8001_chip_isr --> process_oq,// A
.isr_process_oq = process_oq, // B
.....
}
process_oq() --> process_one_iomb() --> mpi_sata_completion()
In 'mpi_sata_completion', "pm8001_ha->lock" is first released.
It means lock is taken before, which is true for
the context A, as 'pm8001_ha->lock' is taken in 'pm8001_chip_isr()'
But for context B there is no lock taken before and pm8001_ha->lock
is unlocked in 'mpi_sata_completion()'. This may unlock the lock
taken in context A. Possible racing ??
If 'pm8001_ha->lock' is taken in 'process_oq()' instead of
'pm8001_chip_isr' then the above issue can be avoided.
Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
Acked-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Static checker is giving following warning:
" error: calling 'spin_unlock_irqrestore()' with bogus flags"
The code flow is as shown below:
process_oq() --> process_one_iomb --> mpi_sata_completion
In 'mpi_sata_completion'
the first call for 'spin_unlock_irqrestore()' is with flags=0,
which is as good as 'spin_unlock_irq()' ( unconditional interrupt
enabling).
So for better performance 'spin_unlock_irqrestore()' can be replaced
with 'spin_unlock_irq()' and 'spin_lock_irqsave()' can be replaced by
'spin_lock_irq()'.
Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
Acked-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This patch updates some PCI ID definitions for new adapters based on the next
generation 64 bit IOA PCI interface chip.
Signed-off-by: Wayne Boyer <wayneb@linux.vnet.ibm.com>
Acked-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This silences a static checker warning. Also we're always adding new
types of firmware, so it might fix a bug in real life some day.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This patch fixes scenario where driver removal should be possible
only when driver is in READY state. Also it removes redundant
invocation of routine disabling SCU interrupts - this method is
called somewhere else in driver deinitialization path.
Signed-off-by: Andrzej Jakowski <andrzej.jakowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
isci occasionally spews messages like:
isci 0000:03:00.0: sci_phy_event_handler: PHY starting substate machine received unexpected event_code b3940000
...which is not very helpful, since we don't know which controller,
which phy, the exact state, or a decode of the event.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Debugging the driver requires tracing the state transtions and tracing
state names is less work than decoding numbers.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
If userspace requests a phy reset, treat that as a request for the phy
to be enabled since that is the effect on hardware.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
If userspace has decided to disable a phy the kernel should honor that
and not inadvertantly re-enable the phy via error recovery. This is
more straightforward in the sata case where link recovery (via
libata-eh) is separate from sas_task cancelling in libsas-eh. Teach
libsas to accept -ENODEV as a successful response from I_T_nexus_reset
('successful' in terms of not escalating further).
This is a more comprehensive fix then "libsas: don't recover 'gone'
devices in sas_ata_hard_reset()", as it is no longer sata-specific.
aic94xx does check the return value from sas_phy_reset() so if the phy
is disabled we proceed with clearing the I_T_nexus.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
If discovery returns 0 for target_port_protocols but shows an attached
sata device, just report SAS_PROTOCOL_SATA in the identify data so
userspace can reliably search for sata devices in the domain.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Before:
$ cat /sys/class/sas_phy/phy-6\:3/device_type
none
$ cat /sys/class/sas_phy/phy-6\:3/target_port_protocols
none
After:
$ cat /sys/class/sas_phy/phy-6\:3/device_type
end device
$ cat /sys/class/sas_phy/phy-6\:3/target_port_protocols
sata
Also downgrade the phy_list_lock to _irq instead of _irqsave since
libsas will never call sas_get_port_device with interrupts disbled.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
libata issues follow up srsts when the controller has a hard time
recording the signature-fis after a reset, or if the link supports port
multipliers. libsas does not support port multipliers and no current
libsas lldds appear to need help retrieving the signature fis. Revert
it for now to remove confusion.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Until all sas_tasks are known to no longer be in-flight this flag gates late
completions from colliding with error handling. However, it must be cleared
prior to the submission of scsi_send_eh_cmnd() requests, otherwise those
commands will never be completed correctly.
This was spotted by slub debug:
=============================================================================
BUG sas_task: Objects remaining on kmem_cache_close()
-----------------------------------------------------------------------------
INFO: Slab 0xffffea001f0eba00 objects=34 used=1 fp=0xffff8807c3aecb00 flags=0x8000000000004080
Pid: 22919, comm: modprobe Not tainted 3.2.0-isci+ #2
Call Trace:
[<ffffffff810fcdcd>] slab_err+0xb0/0xd2
[<ffffffff810e1c50>] ? free_percpu+0x31/0x117
[<ffffffff81100122>] ? kzalloc+0x14/0x16
[<ffffffff81100122>] ? kzalloc+0x14/0x16
[<ffffffff81100486>] kmem_cache_destroy+0x11d/0x270
[<ffffffffa0112bdc>] sas_class_exit+0x10/0x12 [libsas]
[<ffffffff81078fba>] sys_delete_module+0x1c4/0x23c
[<ffffffff814797ba>] ? sysret_check+0x2e/0x69
[<ffffffff8126479e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff81479782>] system_call_fastpath+0x16/0x1b
INFO: Object 0xffff8807c3aed280 @offset=21120
INFO: Allocated in sas_alloc_task+0x22/0x90 [libsas] age=4615311 cpu=2 pid=12966
__slab_alloc.clone.3+0x1d1/0x234
kmem_cache_alloc+0x52/0x10d
sas_alloc_task+0x22/0x90 [libsas]
sas_queuecommand+0x20e/0x230 [libsas]
scsi_send_eh_cmnd+0xd1/0x30c
scsi_eh_try_stu+0x4f/0x6b
scsi_eh_ready_devs+0xba/0x6ef
sas_scsi_recover_host+0xa35/0xab1 [libsas]
scsi_error_handler+0x14b/0x5fa
kthread+0x9d/0xa5
kernel_thread_helper+0x4/0x10
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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 <jack_wang@usish.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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 <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
If the phy is attached to a new sas address unregister the first address
before processing the new attachment.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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 <jack_wang@usish.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Make sas-port naming consistent with the expander-attached case whereby
the phy-id is the last digit in the port name. Otherwise we get the
random behavior of the allocation order.
Reported-by: Patrick Thomson <patrick.s.thomson@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
It's difficult to determine which domain_device is triggering error recovery,
so convert messages like:
sas: ex 5001b4da000e703f phy08:T attached: 5001b4da000e7028
sas: ex 5001b4da000e703f phy09:T attached: 5001b4da000e7029
...
ata7: sas eh calling libata port error handler
ata8: sas eh calling libata port error handler
...into:
sas: ex 5001517e85cfefff phy05:T:9 attached: 5001517e85cfefe5 (stp)
sas: ex 5001517e3b0af0bf phy11:T:8 attached: 5001517e3b0af0ab (stp)
...
sas: ata7: end_device-21:1: dev error handler
sas: ata8: end_device-20:0:5: dev error handler
which shows attached link rate, device type, and associates a
domain_device with its ata_port id to correlate messages emitted from
libata-eh.
As Doug notes, we can also take the opportunity to clarify expander phy
routing capabilities.
[dgilbert@interlog.com: clarify table2table with 'U']
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Holdover from a patch rework, prior to the addition of SAS_DEV_DESTROY
we were holding a reference while the destruct was pending in case the
domain was torn down before the desctruct event ran. That case is
covered by SAS_DEV_DESTROY, and the sas_put_device() just corrupts freed
memory, or worse frees the memory while another agent holds a reference.
Signed-off-by: Maciej Trela <maciej.trela@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Similar to the conversion of the transport-class reset we want bsg
initiated resets to be managed by libata.
Reported-by: Jacek Danecki <jacek.danecki@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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 <andrzej.jakowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
If the top level expander is hot removed, mark all child devices as gone
before unregistration to short circuit futile recovery.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
When scrolling forward through the eh list (in a clear_q scenario) it is
possible to encounter commands that won the completion vs eh race. Rather
than sprinkle more "if (!task)" throughout the handler just make a pass
through the list and delete the race winners before handling the rest.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Prior to commit 61aaff49 "isci: filter broadcast change notifications
during SMP phy resets" we borrowed the MVS_DEV_EH approach from the
mvsas driver for preventing ->lldd_I_T_nexus_reset() events during ata
discovery. This hack was protecting against the old ->phy_reset() in
ata_bus_probe(), but since the conversion to the new error handling this
hack is preventing resets from reaching ata devices.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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 <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Report to libata whether the link to the given domain_device is up and the
signature fis has been received.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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 <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
A hard reset to isci in the direct-attached case is one where the driver
internally manages debouncing the link. In the sas-expander-attached
case a hard reset is one that clears affiliations. The driver should
not be prematurely dropping affiliations at run time, that decision (to
force expander hard resets to ata devices) is left to userspace to
manage. So, arrange for I_T_nexus resets to be sas-link-resets in the
expander-attached case and isci-hard-resets in the direct-attached case.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
It only tracks whether the port is stopping in order to gate new devices
being discovered while the port is stopping. However, since the check
and subsequent handling is unlocked there is nothing to stop the port
from going down immediately after the check.
Driver is already prepared to handle devices arriving on stale ports,
and those will be cleaned up by an eventual ->lldd_dev_gone()
notification.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This field is a holdover from the OS abstraction conversion. The stable
phy to port lookups are done via iphy->ownining_port under scic_lock.
After this conversion to use port->lldd_port the only volatile lookup is
the initial lookup in isci_port_formed(). After that point any lookup
via a successfully notified domain_device is guaranteed to be valid
until the domain_device is destroyed.
Delete ->start_complete as it is only set once and is set as a
consequence of the port going link up, by definition of getting a port
formed event the port is "ready".
While we are correcting port lookups also move the asd_sas_port table
out from under the isci_port. This is to preclude any temptation to use
container_of() to convert an asd_sas_port to an isci_port, the
association is dynamic and under libsas control.
Tested-by: Maciej Trela <maciej.trela@intel.com>
[dmilburn@redhat.com: fix i686 compile error]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
The commands that timeout when a disk is forcibly removed may trigger
libata to attempt recovery of the device. If libsas has decided to
remove the device don't permit ata to continue to issue resets to its
last known phy.
The primary motivation for this patch is hotplug testing by writing 0 to
/sys/class/sas_phy/phyX/enable. Without this check this test leads to
libata issuing a reset and re-enabling the device that wants to be torn
down.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
In the direct-attached case this routine returns the phy on which this
device was first discovered. Which is broken if we want to support
wide-targets, as this phy reference can become stale even though the
port is still active.
In the expander-attached case this routine tries to lookup the phy by
scanning the attached sas addresses of the parent expander, and BUG_ONs
if it can't find it. However since eh and the libsas workqueue run
independently we can still be attempting device recovery via eh after
libsas has recorded the device as detached. This is even easier to hit
now that eh is blocked while device domain rediscovery takes place, and
that libata is fed more timed out commands increasing the chances that
it will try to recover the ata device.
Arrange for dev->phy to always point to a last known good phy, it may be
stale after the port is torn down, but it will catch up for wide port
reconfigurations, and never be NULL.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
No sense in issuing or retrying commands to an expander that has been
removed.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Commit 56dd2c06 "[SCSI] libsas: Don't issue commands to devices that
have been hot-removed" marked the parent device of an end-device as gone
when all the phys to the end device have been deleted.
The expander device is still present until its parent is removed. This
is a benign change until the smp_execute_task() path is taught to check
->gone.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Use ata_wait_after_reset() to poll for link recovery after a reset.
This combined with sas_ha->eh_mutex prevents expander rediscovery from
probing phys in an intermediate state. Local discovery does not have a
mechanism to filter link status changes during this timeout, so it
remains the responsibility of lldds to prevent premature port teardown.
Although once all lldd's support ->lldd_ata_check_ready() that could be
used as a gate to local port teardown.
The signature fis is re-transmitted when the link comes back so we
should be revalidating the ata device class, but that is left to a future
patch.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Once sas_ata_hard_reset() starts honoring the 'deadline' parameter a
pathological configuration could take 25 seconds per ata device
(serialized) to recover. Run per-port recoveries in parallel.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
SAS does not tag SMP requests, and at least one lldd (isci) does not permit
more than one in-flight request at a time.
[jejb: fix sas_init_dev tab issues while we're at it]
Signed-off-by: Jeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
In the case of an explicit sas_phy_enable call to disable a phy,
the LLDD provides the calls to sas_phy_disconnected and the
PHYE_LOSS_OF_SIGNAL event.
NOTE: This assumes that the lldd(s) generate the notification, which
appears to be the case, but only verfied on isci.
Signed-off-by: Jeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Execute the link-reset triggered by sas_phy_enable via
transport_sas_phy_reset so that it can be managed by libata.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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 <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Extend the sas transport class to allow transport users to attach extra
data to a sas_phy (->hostdata). Use this area in libsas to move resets
to workq context in preparation for scheduling ata device resets through
libata-eh.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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 <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
lldds use the SAS_TASK_NEED_DEV_RESET interface to request that eh
perform a reset. In the sata device case defer the commands that
triggered the reset to libata-eh context so it can perform its pre and
post reset management.
In the sas_ata_post_internal() case the reset request is falling on deaf
ears as the sas_task is immediately destroyed without any reset action.
Since it is currently a nop, and likely superfluous given the conversion
to new-style libata-eh, just drop the request.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
libsas-eh if it successfully aborts an ata command will hide the timeout
condition (AC_ERR_TIMEOUT) from libata. The command likely completes
with the all-zero task->task_status it started with. Instead, interpret
a TMF_RESP_FUNC_COMPLETE as the end of the sas_task but keep the scmd
around for libata-eh to handle.
Tested-by: Andrzej Jakowski <andrzej.jakowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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 <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
We invoke task->task_done() to free the task in the eh case, but at this
point we are prepared for scsi_eh_flush_done_q() to finish off the scmd.
Introduce sas_end_task() to capture the final response status from the
lldd and free the task.
Also take the opportunity to kill this warning.
drivers/scsi/libsas/sas_scsi_host.c: In function ‘sas_end_task’:
drivers/scsi/libsas/sas_scsi_host.c:102:3: warning: case value ‘2’ not in enumerated type ‘enum exec_status’ [-Wswitch]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Since sas_ata does not implement ->freeze(), completions for scmds and
internal commands can still arrive concurrent with
ata_scsi_cmd_error_handler() and sas_ata_post_internal() respectively.
By the time either of those is called libata has committed to completing
the qc, and the ATA_PFLAG_FROZEN flag tells sas_ata_task_done() it has
lost the race.
In the sas_ata_post_internal() case we take on the additional
responsibility of freeing the sas_task to close the race with
sas_ata_task_done() freeing the the task while sas_ata_post_internal()
is in the process of invoking ->lldd_abort_task().
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
