linux.git/drivers/ata, branch v3.12-rc2 Linux kernel source tree Merge branch 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata 2013-09-04T01:19:53+00:00 Linus Torvalds torvalds@linux-foundation.org 2013-09-04T01:19:53+00:00 357397a14117f0c2eeafcac06a1f8412a02aa6af Pull libata changes from Tejun Heo: "Two interesting changes. - libata acpi handling has been restructured so that the association between ata devices and ACPI handles are less convoluted. This change shouldn't change visible behavior. - Queued TRIM support, which enables sending TRIM to the device without draining in-flight RW commands, is added. Currently only enabled for ahci (and likely to stay that way for the foreseeable future). Other changes are driver-specific updates / fixes" * 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata: libata: bugfix: Remove __le32 in ata_tf_to_fis() libata: acpi: Remove ata_dev_acpi_handle stub in libata.h libata: Add support for queued DSM TRIM libata: Add support for SEND/RECEIVE FPDMA QUEUED libata: Add H2D FIS "auxiliary" port flag libata: Populate host-to-device FIS "auxiliary" field ata: acpi: rework the ata acpi bind support sata, highbank: send extra clock cycles in SGPIO patterns sata, highbank: set tx_atten override bits devicetree: create a separate binding description for sata_highbank drivers/ata/sata_rcar.c: simplify use of devm_ioremap_resource sata highbank: enable 64-bit DMA mask when using LPAE ata: pata_samsung_cf: add missing __iomem annotation ata: pata_arasan: Staticize local symbols sata_mv: Remove unneeded CONFIG_HAVE_CLK ifdefs ata: use dev_get_platdata() sata_mv: Remove unneeded forward declaration libata: acpi: remove dead code for ata_acpi_(un)bind libata: move 'struct ata_taskfile' and friends from ata.h to libata.h 
Pull libata changes from Tejun Heo:
 "Two interesting changes.

   - libata acpi handling has been restructured so that the association
     between ata devices and ACPI handles are less convoluted.  This
     change shouldn't change visible behavior.

   - Queued TRIM support, which enables sending TRIM to the device
     without draining in-flight RW commands, is added.  Currently only
     enabled for ahci (and likely to stay that way for the foreseeable
     future).

  Other changes are driver-specific updates / fixes"

* 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata:
  libata: bugfix: Remove __le32 in ata_tf_to_fis()
  libata: acpi: Remove ata_dev_acpi_handle stub in libata.h
  libata: Add support for queued DSM TRIM
  libata: Add support for SEND/RECEIVE FPDMA QUEUED
  libata: Add H2D FIS "auxiliary" port flag
  libata: Populate host-to-device FIS "auxiliary" field
  ata: acpi: rework the ata acpi bind support
  sata, highbank: send extra clock cycles in SGPIO patterns
  sata, highbank: set tx_atten override bits
  devicetree: create a separate binding description for sata_highbank
  drivers/ata/sata_rcar.c: simplify use of devm_ioremap_resource
  sata highbank: enable 64-bit DMA mask when using LPAE
  ata: pata_samsung_cf: add missing __iomem annotation
  ata: pata_arasan: Staticize local symbols
  sata_mv: Remove unneeded CONFIG_HAVE_CLK ifdefs
  ata: use dev_get_platdata()
  sata_mv: Remove unneeded forward declaration
  libata: acpi: remove dead code for ata_acpi_(un)bind
  libata: move 'struct ata_taskfile' and friends from ata.h to libata.h
libata: bugfix: Remove __le32 in ata_tf_to_fis() 2013-09-03T14:37:41+00:00 Marc Carino marc.ceeeee@gmail.com 2013-09-01T15:59:01+00:00 86a565e61bcb9574bae3b622799682fef2d855bb The endianness attribute on the 'aux' local variable is wrong, and can lead to wrong endianness on big-endian machines, Signed-off-by: Marc Carino <marc.ceeeee@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> 
The endianness attribute on the 'aux' local variable is wrong, and can
lead to wrong endianness on big-endian machines,

Signed-off-by: Marc Carino <marc.ceeeee@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
libata: acpi: Remove ata_dev_acpi_handle stub in libata.h 2013-08-27T18:07:12+00:00 Aaron Lu aaron.lu@intel.com 2013-08-27T18:07:12+00:00 03f7b802b876904971f23f00f562061309e95e08 The ata_dev_acpi_handle is defined in libata-acpi.c and the only external user is libata-zpodd.c, which is built when CONFIG_ATA_ACPI is set, so there is no need to make an empty stub function for ONFIG_ATA_ACPI case in libata.h. It also causes compile errors due to acpi_handle is not defined when !CONFIG_ACPI. This patch fixes this problem by removing the empty stub. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Aaron Lu <aaron.lu@intel.com> Signed-off-by: Tejun Heo <tj@kernel.org> 
The ata_dev_acpi_handle is defined in libata-acpi.c and the only
external user is libata-zpodd.c, which is built when CONFIG_ATA_ACPI
is set, so there is no need to make an empty stub function for
ONFIG_ATA_ACPI case in libata.h. It also causes compile errors due to
acpi_handle is not defined when !CONFIG_ACPI. This patch fixes this
problem by removing the empty stub.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Merge branch 'acpi-pm' 2013-08-26T23:28:17+00:00 Rafael J. Wysocki rafael.j.wysocki@intel.com 2013-08-26T23:28:17+00:00 0ad4c9a9848fdd46dc422160efd947489a98bbc1 * acpi-pm: ACPI / PM: Add state information to error message in acpi_device_set_power() ACPI / PM: Remove redundant power manageable check from acpi_bus_set_power() ACPI / PM: Use ACPI_STATE_D3_COLD instead of ACPI_STATE_D3 everywhere ACPI / PM: Make messages in acpi_device_set_power() print device names ACPI / PM: Only set power states of devices that are power manageable 
* acpi-pm:
  ACPI / PM: Add state information to error message in acpi_device_set_power()
  ACPI / PM: Remove redundant power manageable check from acpi_bus_set_power()
  ACPI / PM: Use ACPI_STATE_D3_COLD instead of ACPI_STATE_D3 everywhere
  ACPI / PM: Make messages in acpi_device_set_power() print device names
  ACPI / PM: Only set power states of devices that are power manageable
libata: Add support for queued DSM TRIM 2013-08-25T13:39:12+00:00 Marc Carino marc.ceeeee@gmail.com 2013-08-25T06:22:51+00:00 87fb6c31b9ef9ccab9a822b01fc3911f026a29bb Some new SSDs support the queued version of the DSM TRIM command. Let the driver use the new command if supported. Signed-off-by: Marc Carino <marc.ceeeee@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> 
Some new SSDs support the queued version of the DSM TRIM command.
Let the driver use the new command if supported.

Signed-off-by: Marc Carino <marc.ceeeee@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
libata: Add support for SEND/RECEIVE FPDMA QUEUED 2013-08-25T13:39:12+00:00 Marc Carino marc.ceeeee@gmail.com 2013-08-25T06:22:50+00:00 ed36911c747c18525691c0aa0fbe6b918c8eac19 Add support for the following ATA opcodes, which are present in SATA 3.1 and T13 ATA ACS-3: SEND FPDMA QUEUED RECEIVE FPDMA QUEUED Signed-off-by: Marc Carino <marc.ceeeee@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> 
Add support for the following ATA opcodes, which are present
in SATA 3.1 and T13 ATA ACS-3:

        SEND FPDMA QUEUED
        RECEIVE FPDMA QUEUED

Signed-off-by: Marc Carino <marc.ceeeee@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
libata: Add H2D FIS "auxiliary" port flag 2013-08-25T13:39:12+00:00 Marc Carino marc.ceeeee@gmail.com 2013-08-25T06:22:49+00:00 40fb59e75ad197a1c4ca2fbccef85432d8d103f8 Add a new port flag, ATA_FLAG_FPDMA_AUX, used to indicate support for transmission of the H2D FIS 'auxiliary' field. Signed-off-by: Marc Carino <marc.ceeeee@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> 
Add a new port flag, ATA_FLAG_FPDMA_AUX, used to indicate
support for transmission of the H2D FIS 'auxiliary' field.

Signed-off-by: Marc Carino <marc.ceeeee@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
libata: Populate host-to-device FIS "auxiliary" field 2013-08-25T13:39:11+00:00 Marc Carino marc.ceeeee@gmail.com 2013-08-25T06:22:48+00:00 8be5ad9acb7c11b9d717bcdbe3d6de0dab081a39 SATA 3.1 added an "auxiliary" field to the host-to-device FIS. Populate the host-to-device FIS with the new field via the taskfile struct. Signed-off-by: Marc Carino <marc.ceeeee@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> 
SATA 3.1 added an "auxiliary" field to the host-to-device FIS.
Populate the host-to-device FIS with the new field via the
taskfile struct.

Signed-off-by: Marc Carino <marc.ceeeee@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
ata: acpi: rework the ata acpi bind support 2013-08-23T16:09:23+00:00 Aaron Lu aaron.lu@intel.com 2013-08-23T02:17:54+00:00 f1bc1e4c44b1b78fe34431936c60759b5aad5e3f Binding ACPI handle to SCSI device has several drawbacks, namely: 1 During ATA device initialization time, ACPI handle will be needed while SCSI devices are not created yet. So each time ACPI handle is needed, instead of retrieving the handle by ACPI_HANDLE macro, a namespace scan is performed to find the handle for the corresponding ATA device. This is inefficient, and also expose a restriction on calling path not holding any lock. 2 The binding to SCSI device tree makes code complex, while at the same time doesn't bring us any benefit. All ACPI handlings are still done in ATA module, not in SCSI. Rework the ATA ACPI binding code to bind ACPI handle to ATA transport devices(ATA port and ATA device). The binding needs to be done only once, since the ATA transport devices do not go away with hotplug. And due to this, the flush_work call in hotplug handler for ATA bay is no longer needed. Tested on an Intel test platform for binding and runtime power off for ODD(ZPODD) and hard disk; on an ASUS S400C for binding and normal boot and S3, where its SATA port node has _SDD and _GTF control methods when configured as an AHCI controller and its PATA device node has _GTF control method when configured as an IDE controller. SATA PMP binding and ATA hotplug is not tested. Signed-off-by: Aaron Lu <aaron.lu@intel.com> Tested-by: Dirk Griesbach <spamthis@freenet.de> Signed-off-by: Tejun Heo <tj@kernel.org> 
Binding ACPI handle to SCSI device has several drawbacks, namely:
1 During ATA device initialization time, ACPI handle will be needed
  while SCSI devices are not created yet. So each time ACPI handle is
  needed, instead of retrieving the handle by ACPI_HANDLE macro,
  a namespace scan is performed to find the handle for the corresponding
  ATA device. This is inefficient, and also expose a restriction on
  calling path not holding any lock.
2 The binding to SCSI device tree makes code complex, while at the same
  time doesn't bring us any benefit. All ACPI handlings are still done
  in ATA module, not in SCSI.

Rework the ATA ACPI binding code to bind ACPI handle to ATA transport
devices(ATA port and ATA device). The binding needs to be done only once,
since the ATA transport devices do not go away with hotplug. And due to
this, the flush_work call in hotplug handler for ATA bay is no longer
needed.

Tested on an Intel test platform for binding and runtime power off for
ODD(ZPODD) and hard disk; on an ASUS S400C for binding and normal boot
and S3, where its SATA port node has _SDD and _GTF control methods when
configured as an AHCI controller and its PATA device node has _GTF
control method when configured as an IDE controller. SATA PMP binding
and ATA hotplug is not tested.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Tested-by: Dirk Griesbach <spamthis@freenet.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
sata_fsl: save irqs while coalescing 2013-08-20T12:38:23+00:00 Anthony Foiani anthony.foiani@gmail.com 2013-08-20T01:20:30+00:00 99bbdfa6bdcb4bdf5be914a48e9b46941bf30819 Before this patch, I was seeing the following lockdep splat on my MPC8315 (PPC32) target: [ 9.086051] ================================= [ 9.090393] [ INFO: inconsistent lock state ] [ 9.094744] 3.9.7-ajf-gc39503d #1 Not tainted [ 9.099087] --------------------------------- [ 9.103432] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage. [ 9.109431] scsi_eh_1/39 [HC1[1]:SC0[0]:HE0:SE1] takes: [ 9.114642] (&(&host->lock)->rlock){?.+...}, at: [<c02f4168>] sata_fsl_interrupt+0x50/0x250 [ 9.123137] {HARDIRQ-ON-W} state was registered at: [ 9.128004] [<c006cdb8>] lock_acquire+0x90/0xf4 [ 9.132737] [<c043ef04>] _raw_spin_lock+0x34/0x4c [ 9.137645] [<c02f3560>] fsl_sata_set_irq_coalescing+0x68/0x100 [ 9.143750] [<c02f36a0>] sata_fsl_init_controller+0xa8/0xc0 [ 9.149505] [<c02f3f10>] sata_fsl_probe+0x17c/0x2e8 [ 9.154568] [<c02acc90>] driver_probe_device+0x90/0x248 [ 9.159987] [<c02acf0c>] __driver_attach+0xc4/0xc8 [ 9.164964] [<c02aae74>] bus_for_each_dev+0x5c/0xa8 [ 9.170028] [<c02ac218>] bus_add_driver+0x100/0x26c [ 9.175091] [<c02ad638>] driver_register+0x88/0x198 [ 9.180155] [<c0003a24>] do_one_initcall+0x58/0x1b4 [ 9.185226] [<c05aeeac>] kernel_init_freeable+0x118/0x1c0 [ 9.190823] [<c0004110>] kernel_init+0x18/0x108 [ 9.195542] [<c000f6b8>] ret_from_kernel_thread+0x64/0x6c [ 9.201142] irq event stamp: 160 [ 9.204366] hardirqs last enabled at (159): [<c043f778>] _raw_spin_unlock_irq+0x30/0x50 [ 9.212469] hardirqs last disabled at (160): [<c000f414>] reenable_mmu+0x30/0x88 [ 9.219867] softirqs last enabled at (144): [<c002ae5c>] __do_softirq+0x168/0x218 [ 9.227435] softirqs last disabled at (137): [<c002b0d4>] irq_exit+0xa8/0xb4 [ 9.234481] [ 9.234481] other info that might help us debug this: [ 9.240995] Possible unsafe locking scenario: [ 9.240995] [ 9.246898] CPU0 [ 9.249337] ---- [ 9.251776] lock(&(&host->lock)->rlock); [ 9.255878] <Interrupt> [ 9.258492] lock(&(&host->lock)->rlock); [ 9.262765] [ 9.262765] *** DEADLOCK *** [ 9.262765] [ 9.268684] no locks held by scsi_eh_1/39. [ 9.272767] [ 9.272767] stack backtrace: [ 9.277117] Call Trace: [ 9.279589] [cfff9da0] [c0008504] show_stack+0x48/0x150 (unreliable) [ 9.285972] [cfff9de0] [c0447d5c] print_usage_bug.part.35+0x268/0x27c [ 9.292425] [cfff9e10] [c006ace4] mark_lock+0x2ac/0x658 [ 9.297660] [cfff9e40] [c006b7e4] __lock_acquire+0x754/0x1840 [ 9.303414] [cfff9ee0] [c006cdb8] lock_acquire+0x90/0xf4 [ 9.308745] [cfff9f20] [c043ef04] _raw_spin_lock+0x34/0x4c [ 9.314250] [cfff9f30] [c02f4168] sata_fsl_interrupt+0x50/0x250 [ 9.320187] [cfff9f70] [c0079ff0] handle_irq_event_percpu+0x90/0x254 [ 9.326547] [cfff9fc0] [c007a1fc] handle_irq_event+0x48/0x78 [ 9.332220] [cfff9fe0] [c007c95c] handle_level_irq+0x9c/0x104 [ 9.337981] [cfff9ff0] [c000d978] call_handle_irq+0x18/0x28 [ 9.343568] [cc7139f0] [c000608c] do_IRQ+0xf0/0x1a8 [ 9.348464] [cc713a20] [c000fc8c] ret_from_except+0x0/0x14 [ 9.353983] --- Exception: 501 at _raw_spin_unlock_irq+0x40/0x50 [ 9.353983] LR = _raw_spin_unlock_irq+0x30/0x50 [ 9.364839] [cc713af0] [c043db10] wait_for_common+0xac/0x188 [ 9.370513] [cc713b30] [c02ddee4] ata_exec_internal_sg+0x2b0/0x4f0 [ 9.376699] [cc713be0] [c02de18c] ata_exec_internal+0x68/0xa8 [ 9.382454] [cc713c20] [c02de4b8] ata_dev_read_id+0x158/0x594 [ 9.388205] [cc713ca0] [c02ec244] ata_eh_recover+0xd88/0x13d0 [ 9.393962] [cc713d20] [c02f2520] sata_pmp_error_handler+0xc0/0x8ac [ 9.400234] [cc713dd0] [c02ecdc8] ata_scsi_port_error_handler+0x464/0x5e8 [ 9.407023] [cc713e10] [c02ecfd0] ata_scsi_error+0x84/0xb8 [ 9.412528] [cc713e40] [c02c4974] scsi_error_handler+0xd8/0x47c [ 9.418457] [cc713eb0] [c004737c] kthread+0xa8/0xac [ 9.423355] [cc713f40] [c000f6b8] ret_from_kernel_thread+0x64/0x6c This fix was suggested by Bhushan Bharat <R65777@freescale.com>, and was discussed in email at: http://linuxppc.10917.n7.nabble.com/MPC8315-reboot-failure-lockdep-splat-possibly-related-tp75162.html Same patch successfully tested with 3.9.7. linux-next compiled but not tested on hardware. This patch is based off linux-next tag next-20130819 (which is commit 66a01bae29d11916c09f9f5a937cafe7d402e4a5 ) Signed-off-by: Anthony Foiani <anthony.foiani@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org 
Before this patch, I was seeing the following lockdep splat on my
MPC8315 (PPC32) target:

  [    9.086051] =================================
  [    9.090393] [ INFO: inconsistent lock state ]
  [    9.094744] 3.9.7-ajf-gc39503d #1 Not tainted
  [    9.099087] ---------------------------------
  [    9.103432] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
  [    9.109431] scsi_eh_1/39 [HC1[1]:SC0[0]:HE0:SE1] takes:
  [    9.114642]  (&(&host->lock)->rlock){?.+...}, at: [<c02f4168>] sata_fsl_interrupt+0x50/0x250
  [    9.123137] {HARDIRQ-ON-W} state was registered at:
  [    9.128004]   [<c006cdb8>] lock_acquire+0x90/0xf4
  [    9.132737]   [<c043ef04>] _raw_spin_lock+0x34/0x4c
  [    9.137645]   [<c02f3560>] fsl_sata_set_irq_coalescing+0x68/0x100
  [    9.143750]   [<c02f36a0>] sata_fsl_init_controller+0xa8/0xc0
  [    9.149505]   [<c02f3f10>] sata_fsl_probe+0x17c/0x2e8
  [    9.154568]   [<c02acc90>] driver_probe_device+0x90/0x248
  [    9.159987]   [<c02acf0c>] __driver_attach+0xc4/0xc8
  [    9.164964]   [<c02aae74>] bus_for_each_dev+0x5c/0xa8
  [    9.170028]   [<c02ac218>] bus_add_driver+0x100/0x26c
  [    9.175091]   [<c02ad638>] driver_register+0x88/0x198
  [    9.180155]   [<c0003a24>] do_one_initcall+0x58/0x1b4
  [    9.185226]   [<c05aeeac>] kernel_init_freeable+0x118/0x1c0
  [    9.190823]   [<c0004110>] kernel_init+0x18/0x108
  [    9.195542]   [<c000f6b8>] ret_from_kernel_thread+0x64/0x6c
  [    9.201142] irq event stamp: 160
  [    9.204366] hardirqs last  enabled at (159): [<c043f778>] _raw_spin_unlock_irq+0x30/0x50
  [    9.212469] hardirqs last disabled at (160): [<c000f414>] reenable_mmu+0x30/0x88
  [    9.219867] softirqs last  enabled at (144): [<c002ae5c>] __do_softirq+0x168/0x218
  [    9.227435] softirqs last disabled at (137): [<c002b0d4>] irq_exit+0xa8/0xb4
  [    9.234481]
  [    9.234481] other info that might help us debug this:
  [    9.240995]  Possible unsafe locking scenario:
  [    9.240995]
  [    9.246898]        CPU0
  [    9.249337]        ----
  [    9.251776]   lock(&(&host->lock)->rlock);
  [    9.255878]   <Interrupt>
  [    9.258492]     lock(&(&host->lock)->rlock);
  [    9.262765]
  [    9.262765]  *** DEADLOCK ***
  [    9.262765]
  [    9.268684] no locks held by scsi_eh_1/39.
  [    9.272767]
  [    9.272767] stack backtrace:
  [    9.277117] Call Trace:
  [    9.279589] [cfff9da0] [c0008504] show_stack+0x48/0x150 (unreliable)
  [    9.285972] [cfff9de0] [c0447d5c] print_usage_bug.part.35+0x268/0x27c
  [    9.292425] [cfff9e10] [c006ace4] mark_lock+0x2ac/0x658
  [    9.297660] [cfff9e40] [c006b7e4] __lock_acquire+0x754/0x1840
  [    9.303414] [cfff9ee0] [c006cdb8] lock_acquire+0x90/0xf4
  [    9.308745] [cfff9f20] [c043ef04] _raw_spin_lock+0x34/0x4c
  [    9.314250] [cfff9f30] [c02f4168] sata_fsl_interrupt+0x50/0x250
  [    9.320187] [cfff9f70] [c0079ff0] handle_irq_event_percpu+0x90/0x254
  [    9.326547] [cfff9fc0] [c007a1fc] handle_irq_event+0x48/0x78
  [    9.332220] [cfff9fe0] [c007c95c] handle_level_irq+0x9c/0x104
  [    9.337981] [cfff9ff0] [c000d978] call_handle_irq+0x18/0x28
  [    9.343568] [cc7139f0] [c000608c] do_IRQ+0xf0/0x1a8
  [    9.348464] [cc713a20] [c000fc8c] ret_from_except+0x0/0x14
  [    9.353983] --- Exception: 501 at _raw_spin_unlock_irq+0x40/0x50
  [    9.353983]     LR = _raw_spin_unlock_irq+0x30/0x50
  [    9.364839] [cc713af0] [c043db10] wait_for_common+0xac/0x188
  [    9.370513] [cc713b30] [c02ddee4] ata_exec_internal_sg+0x2b0/0x4f0
  [    9.376699] [cc713be0] [c02de18c] ata_exec_internal+0x68/0xa8
  [    9.382454] [cc713c20] [c02de4b8] ata_dev_read_id+0x158/0x594
  [    9.388205] [cc713ca0] [c02ec244] ata_eh_recover+0xd88/0x13d0
  [    9.393962] [cc713d20] [c02f2520] sata_pmp_error_handler+0xc0/0x8ac
  [    9.400234] [cc713dd0] [c02ecdc8] ata_scsi_port_error_handler+0x464/0x5e8
  [    9.407023] [cc713e10] [c02ecfd0] ata_scsi_error+0x84/0xb8
  [    9.412528] [cc713e40] [c02c4974] scsi_error_handler+0xd8/0x47c
  [    9.418457] [cc713eb0] [c004737c] kthread+0xa8/0xac
  [    9.423355] [cc713f40] [c000f6b8] ret_from_kernel_thread+0x64/0x6c

This fix was suggested by Bhushan Bharat <R65777@freescale.com>, and
was discussed in email at:

  http://linuxppc.10917.n7.nabble.com/MPC8315-reboot-failure-lockdep-splat-possibly-related-tp75162.html

Same patch successfully tested with 3.9.7.  linux-next compiled but
not tested on hardware.

This patch is based off linux-next tag next-20130819
(which is commit 66a01bae29d11916c09f9f5a937cafe7d402e4a5 )

Signed-off-by: Anthony Foiani <anthony.foiani@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org