linux-toradex.git/drivers/scsi/ses.c, branch v4.9.131

scsi: ses: don't ask for diagnostic pages repeatedly during probe

2018-03-22T08:17:55+00:00

[ Upstream commit 9c0a50022b8ac7e863e6ec8342fa476fe5d1d75c ]

We are testing if there is a match with the ses device in a loop by
calling ses_match_to_enclosure(), which will issue scsi receive
diagnostics commands to the ses device for every device on the same
host.  On one of our boxes with 840 disks, it takes a long time to load
the driver:

[root@g1b-oss06 ~]# time modprobe ses

real	40m48.247s
user	0m0.001s
sys	0m0.196s

With the patch:

[root@g1b-oss06 ~]# time modprobe ses

real	0m17.915s
user	0m0.008s
sys	0m0.053s

Note that we still need to refresh page 10 when we see a new disk to
create the link.

Signed-off-by: Li Dongyang 
Tested-by: Jason Ozolins 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

scsi: ses: don't get power status of SES device slot on probe

2018-03-22T08:17:48+00:00

[ Upstream commit 75106523f39751390b5789b36ee1d213b3af1945 ]

The commit 08024885a2a3 ("ses: Add power_status to SES device slot")
introduced the 'power_status' attribute to enclosure components and
the associated callbacks.

There are 2 callbacks available to get the power status of a device:
1) ses_get_power_status() for 'struct enclosure_component_callbacks'
2) get_component_power_status() for the sysfs device attribute
(these are available for kernel-space and user-space, respectively.)

However, despite both methods being available to get power status
on demand, that commit also introduced a call to get power status
in ses_enclosure_data_process().

This dramatically increased the total probe time for SCSI devices
on larger configurations, because ses_enclosure_data_process() is
called several times during the SCSI devices probe and loops over
the component devices (but that is another problem, another patch).

That results in a tremendous continuous hammering of SCSI Receive
Diagnostics commands to the enclosure-services device, which does
delay the total probe time for the SCSI devices __significantly__:

  Originally, ~34 minutes on a system attached to ~170 disks:

    [ 9214.490703] mpt3sas version 13.100.00.00 loaded
    ...
    [11256.580231] scsi 17:0:177:0: qdepth(16), tagged(1), simple(0),
                   ordered(0), scsi_level(6), cmd_que(1)

  With this patch, it decreased to ~2.5 minutes -- a 13.6x faster

    [ 1002.992533] mpt3sas version 13.100.00.00 loaded
    ...
    [ 1151.978831] scsi 11:0:177:0: qdepth(16), tagged(1), simple(0),
                   ordered(0), scsi_level(6), cmd_que(1)

Back to the commit discussion.. on the ses_get_power_status() call
introduced in ses_enclosure_data_process(): impact of removing it.

That may possibly be in place to initialize the power status value
on device probe.  However, those 2 functions available to retrieve
that value _do_ automatically refresh/update it.  So the potential
benefit would be a direct access of the 'power_status' field which
does not use the callbacks...

But the only reader of 'struct enclosure_component::power_status'
is the get_component_power_status() callback for sysfs attribute,
and it _does_ check for and call the .get_power_status callback,
(which indeed is defined and implemented by that commit), so the
power status value is, again, automatically updated.

So, the remaining potential for a direct/non-callback access to
the power_status attribute would be out-of-tree modules -- well,
for those, if they are for whatever reason interested in values
that are set during device probe and not up-to-date by the time
they need it.. well, that would be curious.

Well, to handle that more properly, set the initial power state
value to '-1' (i.e., uninitialized) instead of '1' (power 'on'),
and check for it in that callback which may do an direct access
to the field value _if_ a callback function is not defined.

Signed-off-by: Mauricio Faria de Oliveira 
Fixes: 08024885a2a3 ("ses: Add power_status to SES device slot")
Reviewed-by: Dan Williams 
Reviewed-by: Song Liu 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

scsi: ses: Fix SAS device detection in enclosure

2017-01-26T07:24:44+00:00

commit 9373eba6cfae48911b977d14323032cd5d161aae upstream.

The call to scsi_is_sas_rphy() needs to be made on the SAS end_device,
not on the SCSI device.

Fixes: 835831c57e9b ("ses: use scsi_is_sas_rphy instead of is_sas_attached")
Signed-off-by: Ewan D. Milne 
Reviewed-by: Johannes Thumshirn 
Reviewed-by: James Bottomley 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Greg Kroah-Hartman

scsi: ses: use scsi_is_sas_rphy instead of is_sas_attached

2016-08-19T02:22:19+00:00

Use scsi_is_sas_rphy() instead of is_sas_attached() to decide whether we
should obtain the SAS address from a scsi device or not. This will
prevent us from tripping on the BUG_ON() in sas_sdev_to_rdev() if the
rphy isn't attached to the SAS transport class, like it is with hpsa's
logical devices.

Fixes: 3f8d6f2a0 ('ses: fix discovery of SATA devices in SAS enclosures')
Signed-off-by: Johannes Thumshirn 
Reviewed-by: James E.J. Bottomley 
Signed-off-by: Martin K. Petersen

ses: Fix racy cleanup of /sys in remove_dev()

2016-08-12T21:40:51+00:00

Currently we free the resources backing the enclosure device before we
call device_unregister(). This is racy: during rmmod of low-level SCSI
drivers that hook into enclosure, we end up with a small window of time
during which writing to /sys can OOPS. Example trace with mpt3sas:

  general protection fault: 0000 [#1] SMP KASAN
  Modules linked in: mpt3sas(-) <...>
  RIP: [] ses_get_page2_descriptor.isra.6+0x38/0x220 [ses]
  Call Trace:
   [] ses_set_fault+0xf4/0x400 [ses]
   [] set_component_fault+0xa9/0xf0 [enclosure]
   [] dev_attr_store+0x3c/0x70
   [] sysfs_kf_write+0x115/0x180
   [] kernfs_fop_write+0x275/0x3a0
   [] __vfs_write+0xe0/0x3e0
   [] vfs_write+0x13f/0x4a0
   [] SyS_write+0x111/0x230
   [] entry_SYSCALL_64_fastpath+0x13/0x94

Fortunately the solution is extremely simple: call device_unregister()
before we free the resources, and the race no longer exists. The driver
core holds a reference over ->remove_dev(), so AFAICT this is safe.

Signed-off-by: Calvin Owens 
Reviewed-by: James Bottomley 
Signed-off-by: Martin K. Petersen

ses: fix discovery of SATA devices in SAS enclosures

2015-12-19T03:29:50+00:00

The current discovery routines use the VPD 0x83 inquiry page to find
the device SAS address and match it to the end point in the enclosure.
This doesn't work for SATA devices because expanders (or hosts) simply
make up an endpoint address for STP and thus the address returned by
the VPD page never matches.  Instead of doing this, for SAS attached
devices, match by the direct endpoint address instead.

Signed-off-by: James Bottomley

ses: fix additional element traversal bug

2015-12-11T19:05:57+00:00

KASAN found that our additional element processing scripts drop off
the end of the VPD page into unallocated space.  The reason is that
not every element has additional information but our traversal
routines think they do, leading to them expecting far more additional
information than is present.  Fix this by adding a gate to the
traversal routine so that it only processes elements that are expected
to have additional information (list is in SES-2 section 6.1.13.1:
Additional Element Status diagnostic page overview)

Reported-by: Pavel Tikhomirov 
Tested-by: Pavel Tikhomirov 
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley

ses: Fix problems with simple enclosures

2015-12-10T16:14:03+00:00

Simple enclosure implementations (mostly USB) are allowed to return only
page 8 to every diagnostic query.  That really confuses our
implementation because we assume the return is the page we asked for and
end up doing incorrect offsets based on bogus information leading to
accesses outside of allocated ranges.  Fix that by checking the page
code of the return and giving an error if it isn't the one we asked for.
This should fix reported bugs with USB storage by simply refusing to
attach to enclosures that behave like this.  It's also good defensive
practise now that we're starting to see more USB enclosures.

Reported-by: Andrea Gelmini 
Cc: stable@vger.kernel.org
Reviewed-by: Ewan D. Milne 
Reviewed-by: Tomas Henzl 
Signed-off-by: James Bottomley

ses: Add power_status to SES device slot

2015-01-09T14:44:19+00:00

Add power_status to SES device slot, so we can power on/off the
HDDs behind the enclosure.

Check firmware status in ses_set_* before sending control pages to
firmware.

Signed-off-by: Song Liu 
Acked-by: Dan Williams 
Reviewed-by: Jens Axboe 
Cc: Hannes Reinecke 
Signed-off-by: Christoph Hellwig

ses: add reliable slot attribute

2015-01-09T14:44:19+00:00

The name provided by firmware is in a vendor specific format, publish
the slot number to have a reliable mechanism for identifying slots
across firmware implementations.  If the enclosure does not provide a
slot number fallback to the component number which is guaranteed unique,
and usually mirrors the slot number.

Cleaned up the unused ses_component.desc in the process.

Signed-off-by: Dan Williams 
Signed-off-by: Song Liu 
Reviewed-by: Jens Axboe 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Christoph Hellwig