linux-toradex.git/drivers/scsi/libsas/sas_init.c, branch v3.17.4

[SCSI] libsas: suspend / resume support

2012-08-24T09:10:23+00:00

libsas power management routines to suspend and recover the sas domain
based on a model where the lldd is allowed and expected to be
"forgetful".

sas_suspend_ha - disable event processing allowing the lldd to take down
                 links without concern for causing hotplug events.
                 Regardless of whether the lldd actually posts link down
                 messages libsas notifies the lldd that all
                 domain_devices are gone.

sas_prep_resume_ha - on the way back up before the lldd starts link
                     training clean out any spurious events that were
                     generated on the way down, and re-enable event
                     processing

sas_resume_ha - after the lldd has started and decided that all phys
		have posted link-up events this routine is called to let
		libsas start it's own timeout of any phys that did not
		resume.  After the timeout an lldd can cancel the
                phy teardown by posting a link-up event.

Storage for ex_change_count (u16) and phy_change_count (u8) are changed
to int so they can be set to -1 to indicate 'invalidated'.

Signed-off-by: Dan Williams 
Reviewed-by: Jacek Danecki 
Tested-by: Maciej Patelczyk 
Acked-by: Alan Stern 
Signed-off-by: James Bottomley

[SCSI] libsas: trim sas_task of slow path infrastructure

2012-07-20T07:58:54+00:00

The timer and the completion are only used for slow path tasks (smp, and
lldd tmfs), yet we incur the allocation space and cpu setup time for
every fast path task.

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

[SCSI] libsas: enforce eh strategy handlers only in eh context

2012-07-20T07:58:50+00:00

The strategy handlers may be called in places that are problematic for
libsas (i.e. sata resets outside of domain revalidation filtering /
libata link recovery), or problematic for userspace (non-blocking ioctl
to sleeping reset functions).  However, these routines are also called
for eh escalations and recovery of scsi_eh_prep_cmnd(), so permit them
as long as we are running in the host's error handler, otherwise arrange
for them to be triggered in eh_context.

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

[SCSI] libata, libsas: introduce sched_eh and end_eh port ops

2012-07-20T07:58:45+00:00

When managing shost->host_eh_scheduled libata assumes that there is a
1:1 shost-to-ata_port relationship.  libsas creates a 1:N relationship
so it needs to manage host_eh_scheduled cumulatively at the host level.
The sched_eh and end_eh port port ops allow libsas to track when domain
devices enter/leave the "eh-pending" state under ha->lock (previously
named ha->state_lock, but it is no longer just a lock for ha->state
changes).

Since host_eh_scheduled indicates eh without backing commands pinning
the device it can be deallocated at any time.  Move the taking of the
domain_device reference under the port_lock to guarantee that the
ata_port stays around for the duration of eh.

Reviewed-by: Jacek Danecki 
Acked-by: Jeff Garzik 
Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley

[SCSI] libsas: introduce sas_work to fix sas_drain_work vs sas_queue_work

2012-04-23T11:03:39+00:00

When requeuing work to a draining workqueue the last work instance may
not be idle, so sas_queue_work() must not touch work->entry.  Introduce
sas_work with a drain_node list_head to have a private list for
collecting work deferred due to drain collision.

Fixes reports like:
  BUG: unable to handle kernel NULL pointer dereference at           (null)
  IP: [] process_one_work+0x2e/0x338

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

[SCSI] libsas: don't recover end devices attached to disabled phys

2012-02-29T21:42:51+00:00

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 
Signed-off-by: James Bottomley

[SCSI] libsas: fix sas_unregister_ports vs sas_drain_work

2012-02-29T21:27:09+00:00

We need to hold drain_mutex across the unregistration as port down events
queue device removal as chained events, so we need to make sure no other
drainers are active.

[ 1118.673968] WARNING: at kernel/workqueue.c:996 __queue_work+0x11a/0x326()
[ 1118.681982] Hardware name: S2600CP
[ 1118.686193] Modules linked in: isci(-) libsas scsi_transport_sas nls_utf8
ipv6 uinput sg iTCO_wdt iTCO_vendor_support i2c_i801 i2c_core ioatdma dca
sd_mod sr_mod cdrom ahci libahci libata [last unloaded: scsi_transport_sas]
[ 1118.709893] Pid: 6831, comm: rmmod Not tainted 3.2.0-isci+ #1
[ 1118.716727] Call Trace:
[ 1118.719867]  [] warn_slowpath_common+0x85/0x9d
[ 1118.727000]  [] warn_slowpath_null+0x1a/0x1c
[ 1118.733942]  [] __queue_work+0x11a/0x326
[ 1118.740481]  [] queue_work_on+0x1b/0x22
[ 1118.746925]  [] queue_work+0x37/0x3e
[ 1118.753105]  [] ? sas_discover_event+0x55/0x82 [libsas]
[ 1118.761094]  [] scsi_queue_work+0x42/0x44
[ 1118.767717]  [] sas_discover_event+0x69/0x82 [libsas]
[ 1118.775509]  [] sas_unregister_dev+0xc3/0xcc [libsas]
[ 1118.783319]  [] sas_unregister_domain_devices+0x4a/0xc8 [libsas]
[ 1118.792731]  [] sas_deform_port+0x60/0x1a6 [libsas]
[ 1118.800339]  [] sas_unregister_ports+0x33/0x44 [libsas]
[ 1118.808342]  [] sas_unregister_ha+0x41/0x6b [libsas]
[ 1118.816055]  [] isci_unregister+0x22/0x4d [isci]
[ 1118.823384]  [] isci_pci_remove+0x2e/0x60 [isci]

Reported-by: Jacek Danecki 
Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley

[SCSI] libsas: route local link resets through ata-eh

2012-02-29T21:25:32+00:00

Similar to the conversion of the transport-class reset we want bsg
initiated resets to be managed by libata.

Reported-by: Jacek Danecki 
Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley

[SCSI] libsas: Remove redundant phy state notification calls.

2012-02-19T20:20:09+00:00

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

[SCSI] libsas: sas_phy_enable via transport_sas_phy_reset

2012-02-19T20:18:01+00:00

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 
Signed-off-by: James Bottomley