Fold it into drop_fpu(). Phew, one less FPU function to pay attention
to.

No functionality change.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

flush_thread() -> drop_init_fpu() is suboptimal and confusing. It does
drop_fpu() or restore_init_xstate() depending on !use_eager_fpu(). But
flush_thread() too checks eagerfpu right after that, and if it is true
then restore_init_xstate() just burns CPU for no reason. We are going to
load init_xstate_buf again after we set used_math()/user_has_fpu(), until
then the FPU state can't survive after switch_to().

Remove it, and change the "if (!use_eager_fpu())" to call drop_fpu().
While at it, clean up the tsk/current usage.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Link: http://lkml.kernel.org/r/20150313173030.GA31217@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Change flush_thread() to do user_fpu_begin() and restore_init_xstate()
instead of math_state_restore().

Note: "TODO: cleanup this horror" is still valid. We do not need
init_fpu() at all, we only need fpu_alloc() and memset(0). But this
needs other changes, in particular user_fpu_begin() should set
used_math().
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Link: http://lkml.kernel.org/r/20150311173449.GE5032@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Extract the "use_eager_fpu()" code from drop_init_fpu() into a new,
simple helper restore_init_xstate(). The next patch adds another user.

- It is not clear why we do not check use_fxsr() like fpu_restore_checking()
  does. eager_fpu_init_bp() calls setup_init_fpu_buf() too, and we have the
  "eagerfpu=on" kernel option.

- Ignoring the fact that init_xstate_buf is "struct xsave_struct *", not
  "union thread_xstate *", it is not clear why we can not simply use
  fpu_restore_checking() and avoid the code duplication.

- It is not clear why we can't call setup_init_fpu_buf() unconditionally
  to always create init_xstate_buf(). Then do_device_not_available() path
  (at least) could use restore_init_xstate() too. It doesn't need to init
  fpu->state, its content doesn't matter until unlazy_fpu()/__switch_to()/etc
  which overwrites this memory anyway.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Link: http://lkml.kernel.org/r/20150311173429.GD5032@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently, user_fpu_begin() has a single caller and it is not clear why
do we actually need it and why we should not worry about preemption
right after preempt_enable().
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Link: http://lkml.kernel.org/r/20150311173409.GC5032@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NIngo Molnar <mingo@kernel.org>

Pull bugfix for md from Neil Brown:
 "One fix for md in 4.0-rc4

  Regression in recent patch causes crash on error path"

* tag 'md/4.0-rc4-fix' of git://neil.brown.name/md:
  md: fix problems with freeing private data after ->run failure.

Pull driver core fixes from Greg KH:
 "Here are two bugfixes for things reported.  One regression in kernfs,
  and another issue fixed in the LZ4 code that was fixed in the
  "upstream" codebase that solves a reported kernel crash

  Both have been in linux-next for a while"

* tag 'driver-core-4.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  LZ4 : fix the data abort issue
  kernfs: handle poll correctly on 'direct_read' files.

Pull char/misc fixes from Greg KH:
 "Here are three fixes for 4.0-rc5 that revert 3 PCMCIA patches that
  were merged in 4.0-rc1 that cause regressions.  So let's revert them
  for now and they will be reworked and resent sometime in the future.

  All have been tested in linux-next for a while"

* tag 'char-misc-4.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  Revert "pcmcia: add a new resource manager for non ISA systems"
  Revert "pcmcia: fix incorrect bracketing on a test"
  Revert "pcmcia: add missing include for new pci resource handler"

Pull staging driver fixes from Greg KH:
 "Here are four small staging driver fixes, all for the vt6656 and
  vt6655 drivers, that resolve some reported issues with them.

  All of these patches have been in linux next for a while"

* tag 'staging-4.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  vt6655: Fix late setting of byRFType.
  vt6655: RFbSetPower fix missing rate RATE_12M
  staging: vt6656: vnt_rf_setpower: fix missing rate RATE_12M
  staging: vt6655: vnt_tx_packet fix dma_idx selection.

Pull tty/serial driver fix from Greg KH:
 "Here's a single 8250 serial driver that fixes a reported deadlock with
  the serial console and the tty driver.

  It's been in linux-next for a while now"

* tag 'tty-4.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: 8250_dw: Fix deadlock in LCR workaround

Pull USB / PHY driver fixes from Greg KH:
 "Here's a number of USB and PHY driver fixes for 4.0-rc5.

  The largest thing here is a revert of a gadget function driver patch
  that removes 500 lines of code.  Other than that, it's a number of
  reported bugs fixes and new quirk/id entries.

  All have been in linux-next for a while"

* tag 'usb-4.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (33 commits)
  usb: common: otg-fsm: only signal connect after switching to peripheral
  uas: Add US_FL_NO_ATA_1X for Initio Corporation controllers / devices
  USB: ehci-atmel: rework clk handling
  MAINTAINERS: add entry for USB OTG FSM
  usb: chipidea: otg: add a_alt_hnp_support response for B device
  phy: omap-usb2: Fix missing clk_prepare call when using old dt name
  phy: ti/omap: Fix modalias
  phy: core: Fixup return value of phy_exit when !pm_runtime_enabled
  phy: miphy28lp: Convert to devm_kcalloc and fix wrong sizof
  phy: miphy365x: Convert to devm_kcalloc and fix wrong sizeof
  phy: twl4030-usb: Remove redundant assignment for twl->linkstat
  phy: exynos5-usbdrd: Fix off-by-one valid value checking for args->args[0]
  phy: Find the right match in devm_phy_destroy()
  phy: rockchip-usb: Fixup rockchip_usb_phy_power_on failure path
  phy: ti-pipe3: Simplify ti_pipe3_dpll_wait_lock implementation
  phy: samsung-usb2: Remove NULL terminating entry from phys array
  phy: hix5hd2-sata: Check return value of platform_get_resource
  phy: exynos-dp-video: Kill exynos_dp_video_phy_pwr_isol function
  Revert "usb: gadget: zero: Add support for interrupt EP"
  Revert "xhci: Clear the host side toggle manually when endpoint is 'soft reset'"
  ...

Pull slave dmaengine fixes from Vinod Koul:
 "Four fixes for dw, pl08x, imx-sdma and at_hdmac driver.  Nothing
  unusual here, simple fixes to these drivers"

* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: pl08x: Define capabilities for generic capabilities reporting
  dmaengine: dw: append MODULE_ALIAS for platform driver
  dmaengine: imx-sdma: switch to dynamic context mode after script loaded
  dmaengine: at_hdmac: Fix calculation of the residual bytes

Pull power management and ACPI fixes from Rafael Wysocki:
 "These are fixes for recent regressions (PCI/ACPI resources and at91
  RTC locking), a stable-candidate powercap RAPL driver fix and two ARM
  cpuidle fixes (one stable-candidate too).

  Specifics:

   - Revert a recent PCI commit related to IRQ resources management that
     introduced a regression for drivers attempting to bind to devices
     whose previous drivers did not balance pci_enable_device() and
     pci_disable_device() as expected (Rafael J Wysocki).

   - Fix a deadlock in at91_rtc_interrupt() introduced by a typo in a
     recent commit related to wakeup interrupt handling (Dan Carpenter).

   - Allow the power capping RAPL (Running-Average Power Limit) driver
     to use different energy units for domains within one CPU package
     which is necessary to handle Intel Haswell EP processors correctly
     (Jacob Pan).

   - Improve the cpuidle mvebu driver's handling of Armada XP SoCs by
     updating the target residency and exit latency numbers for those
     chips (Sebastien Rannou).

   - Prevent the cpuidle mvebu driver from calling cpu_pm_enter() twice
     in a row before cpu_pm_exit() is called on the same CPU which
     breaks the core's assumptions regarding the usage of those
     functions (Gregory Clement)"

* tag 'pm+acpi-4.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "x86/PCI: Refine the way to release PCI IRQ resources"
  rtc: at91rm9200: double locking bug in at91_rtc_interrupt()
  powercap / RAPL: handle domains with different energy units
  cpuidle: mvebu: Update cpuidle thresholds for Armada XP SOCs
  cpuidle: mvebu: Fix the CPU PM notifier usage

Pull drm updates from Dave Airlie:
 "A bunch of fixes across drivers:

  radeon:
     disable two ended allocation for now, it breaks some stuff

  amdkfd:
     misc fixes

  nouveau:
     fix irq loop problem, add basic support for GM206 (new hw)

  i915:
     fix some WARNs people were seeing

  exynos:
     fix some iommu interactions causing boot failures"

* git://people.freedesktop.org/~airlied/linux:
  drm/radeon: drop ttm two ended allocation
  drm/exynos: fix the initialization order in FIMD
  drm/exynos: fix typo config name correctly.
  drm/exynos: Check for NULL dereference of crtc
  drm/exynos: IS_ERR() vs NULL bug
  drm/exynos: remove unused files
  drm/i915: Make sure the primary plane is enabled before reading out the fb state
  drm/nouveau/bios: fix i2c table parsing for dcb 4.1
  drm/nouveau/device/gm100: Basic GM206 bring up (as copy of GM204)
  drm/nouveau/device: post write to NV_PMC_BOOT_1 when flipping endian switch
  drm/nouveau/gr/gf100: fix some accidental or'ing of buffer addresses
  drm/nouveau/fifo/nv04: remove the loop from the interrupt handler
  drm/radeon: Changing number of compute pipe lines
  drm/amdkfd: Fix SDMA queue init. in non-HWS mode
  drm/amdkfd: destroy mqd when destroying kernel queue
  drm/i915: Ensure plane->state->fb stays in sync with plane->fb

Merge tag 'devicetree-fixes-for-4.0-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

Pull more DeviceTree fixes vfom Rob Herring:

 - revert setting stdout-path as preferred console.  This caused
   regressions in PowerMACs and other systems.

 - yet another fix for stdout-path option parsing.

 - fix error path handling in of_irq_parse_one

* tag 'devicetree-fixes-for-4.0-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  Revert "of: Fix premature bootconsole disable with 'stdout-path'"
  of: handle both '/' and ':' in path strings
  of: unittest: Add option string test case with longer path
  of/irq: Fix of_irq_parse_one() returned error codes

Pull SCSI target fixes from Nicholas Bellinger:
 "Here are current target-pending fixes for v4.0-rc5 code that have made
  their way into the queue over the last weeks.

  The fixes this round include:

   - Fix long-standing iser-target logout bug related to early
     conn_logout_comp completion, resulting in iscsi_conn use-after-tree
     OOpsen.  (Sagi + nab)

   - Fix long-standing tcm_fc bug in ft_invl_hw_context() failure
     handing for DDP hw offload.  (DanC)

   - Fix incorrect use of unprotected __transport_register_session() in
     tcm_qla2xxx + other single local se_node_acl fabrics.  (Bart)

   - Fix reference leak in target_submit_cmd() -> target_get_sess_cmd()
     for ack_kref=1 failure path.  (Bart)

   - Fix pSCSI backend ->get_device_type() statistics OOPs with
     un-configured device.  (Olaf + nab)

   - Fix virtual LUN=0 target_configure_device failure OOPs at modprobe
     time.  (Claudio + nab)

   - Fix FUA write false positive failure regression in v4.0-rc1 code.
     (Christophe Vu-Brugier + HCH)"

* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
  target: do not reject FUA CDBs when write cache is enabled but emulate_write_cache is 0
  target: Fix virtual LUN=0 target_configure_device failure OOPs
  target/pscsi: Fix NULL pointer dereference in get_device_type
  tcm_fc: missing curly braces in ft_invl_hw_context()
  target: Fix reference leak in target_get_sess_cmd() error path
  loop/usb/vhost-scsi/xen-scsiback: Fix use of __transport_register_session
  tcm_qla2xxx: Fix incorrect use of __transport_register_session
  iscsi-target: Avoid early conn_logout_comp for iser connections
  Revert "iscsi-target: Avoid IN_LOGOUT failure case for iser-target"
  target: Disallow changing of WRITE cache/FUA attrs after export

Pull devicemapper fixes from Mike Snitzer:
 "A handful of stable fixes for DM:
   - fix thin target to always zero-fill reads to unprovisioned blocks
   - fix to interlock device destruction's suspend from internal
     suspends
   - fix 2 snapshot exception store handover bugs
   - fix dm-io to cope with DISCARD and WRITE_SAME capabilities changing"

* tag 'dm-4.0-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm io: deal with wandering queue limits when handling REQ_DISCARD and REQ_WRITE_SAME
  dm snapshot: suspend merging snapshot when doing exception handover
  dm snapshot: suspend origin when doing exception handover
  dm: hold suspend_lock while suspending device during device deletion
  dm thin: fix to consistently zero-fill reads to unprovisioned blocks

Pull btrfs fixes from Chris Mason:
 "Most of these are fixing extent reservation accounting, or corners
  with tree writeback during commit.

  Josef's set does add a test, which isn't strictly a fix, but it'll
  keep us from making this same mistake again"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix outstanding_extents accounting in DIO
  Btrfs: add sanity test for outstanding_extents accounting
  Btrfs: just free dummy extent buffers
  Btrfs: account merges/splits properly
  Btrfs: prepare block group cache before writing
  Btrfs: fix ASSERT(list_empty(&cur_trans->dirty_bgs_list)
  Btrfs: account for the correct number of extents for delalloc reservations
  Btrfs: fix merge delalloc logic
  Btrfs: fix comp_oper to get right order
  Btrfs: catch transaction abortion after waiting for it
  btrfs: fix sizeof format specifier in btrfs_check_super_valid()

Pull nfsd bufix from Bruce Fields:
 "This is a fix for a crash easily triggered by 4.1 activity to a server
  built with CONFIG_NFSD_PNFS.

  There are some more bugfixes queued up that I intend to pass along
  next week, but this is the most critical"

* 'for-4.0' of git://linux-nfs.org/~bfields/linux:
  Subject: nfsd: don't recursively call nfsd4_cb_layout_fail

Pull UBI fix from Artem Bityutskiy:
 "This fixes a bug introduced during the v4.0 merge window where we
  forgot to put braces where they should be"

* tag 'upstream-4.0-rc5' of git://git.infradead.org/linux-ubifs:
  UBI: fix missing brace control flow

Pull arm64 fixes from Catalin Marinas:

 - mm switching fix where the kernel pgd ends up in the user TTBR0 after
   returning from an EFI run-time services call

 - fix __GFP_ZERO handling for atomic pool and CMA DMA allocations (the
   generic code does get the gfp flags, so it's left with the arch code
   to memzero accordingly)

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Honor __GFP_ZERO in dma allocations
  arm64: efi: don't restore TTBR0 if active_mm points at init_mm

Pull ARM fixes from Russell King:
 "Another few ARM fixes.  Fabrice fixed the L2 cache DT parsing to allow
  prefetch configuration to be specified even when the cache size
  parsing fails.

  Laura noticed that the setting of page attributes wasn't working for
  modules due to is_module_addr() always returning false.

  Marc Gonzalez (aka Mason) noticed a potential latent bug with the way
  we read one of the CPUID registers (where we could attempt to read a
  non-present CPUID register which may fault.)

  I've fixed an issue where 32-bit DMA masks were failing with memory
  which extended to the top of physical address space, and I've also
  added debugging output of the page tables when we hit a data access
  exception which we don't specifically handle - prompted by the lack of
  information in a bug report"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8313/1: Use read_cpuid_ext() macro instead of inline asm
  ARM: 8311/1: Don't use is_module_addr in setting page attributes
  ARM: 8310/1: l2c: Fix prefetch settings dt parsing
  ARM: dump pgd, pmd and pte states on unhandled data abort faults
  ARM: dma-api: fix off-by-one error in __dma_supported()

* pm-cpuidle:
  cpuidle: mvebu: Update cpuidle thresholds for Armada XP SOCs
  cpuidle: mvebu: Fix the CPU PM notifier usage

* powercap:
  powercap / RAPL: handle domains with different energy units

* irq-pm:
  rtc: at91rm9200: double locking bug in at91_rtc_interrupt()

* acpi-resources:
  Revert "x86/PCI: Refine the way to release PCI IRQ resources"

If ->run() fails, it can either free the data structures it
allocated, or leave that task to ->free() which will be called
on failures.

However:
  md.c calls ->free() even if ->private_data is NULL, which
     causes problems in some personalities.
  raid0.c frees the data, but doesn't clear ->private_data,
     which will become a problem when we fix md.c

So better fix both these issues at once.
Reported-by: NRichard W.M. Jones <rjones@redhat.com>
Fixes: 5aa61f42
URL: https://bugzilla.kernel.org/show_bug.cgi?id=94381Signed-off-by: NNeilBrown <neilb@suse.de>

Current implementation doesn't zero out the pages allocated.
Honor the __GFP_ZERO flag and zero out if set.

Cc: <stable@vger.kernel.org> # v3.14+
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NSuzuki K. Poulose <suzuki.poulose@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

init_mm isn't a normal mm: it has swapper_pg_dir as its pgd (which
contains kernel mappings) and is used as the active_mm for the idle
thread.

When restoring the pgd after an EFI call, we write current->active_mm
into TTBR0. If the current task is actually the idle thread (e.g. when
initialising the EFI RTC before entering userspace), then the TLB can
erroneously populate itself with junk global entries as a result of
speculative table walks.

When we do eventually return to userspace, the task can end up hitting
these junk mappings leading to lockups, corruption or crashes.

This patch fixes the problem in the same way as the CPU suspend code by
ensuring that we never switch to the init_mm in efi_set_pgd and instead
point TTBR0 at the zero page. A check is also added to cpu_switch_mm to
BUG if we get passed swapper_pg_dir.
Reviewed-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Fixes: f3cdfd23 ("arm64/efi: move SetVirtualAddressMap() to UEFI stub")
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

Commit b4b55cda (Refine the way to release PCI IRQ resources)
introduced a regression in the PCI IRQ resource management by causing
the IRQ resource of a device, established when pci_enabled_device()
is called on a fully disabled device, to be released when the driver
is unbound from the device, regardless of the enable_cnt.

This leads to the situation that an ill-behaved driver can now make a
device unusable to subsequent drivers by an imbalance in their use of
pci_enable/disable_device().  That is a serious problem for secondary
drivers like vfio-pci, which are innocent of the transgressions of
the previous driver.

Since the solution of this problem is not immediate and requires
further discussion, revert commit b4b55cda and the issue it was
supposed to address (a bug related to xen-pciback) will be taken
care of in a different way going forward.
Reported-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Backporting a couple of plane related fixes from drm-next to v4.0.

* tag 'drm-intel-fixes-2015-03-19' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Make sure the primary plane is enabled before reading out the fb state
  drm/i915: Ensure plane->state->fb stays in sync with plane->fb

Merge tag 'drm-amdkfd-fixes-2015-03-19' of git://people.freedesktop.org/~gabbayo/linux into drm-fixes

- Fixing SDMA initialization when in non-HWS mode (debug mode)
- Memory leak fix when destroying kernel queue
- Fix number of available compute pipelines according to new firmware

* tag 'drm-amdkfd-fixes-2015-03-19' of git://people.freedesktop.org/~gabbayo/linux:
  drm/radeon: Changing number of compute pipe lines
  drm/amdkfd: Fix SDMA queue init. in non-HWS mode
  drm/amdkfd: destroy mqd when destroying kernel queue

A check that rejects a CDB with FUA bit set if no write cache is
emulated was added by the following commit:

  fde9f50f target: Add sanity checks for DPO/FUA bit usage

The condition is as follows:

  if (!dev->dev_attrib.emulate_fua_write ||
      !dev->dev_attrib.emulate_write_cache)

However, this check is wrong if the backend device supports WCE but
"emulate_write_cache" is disabled.

This patch uses se_dev_check_wce() (previously named
spc_check_dev_wce) to invoke transport->get_write_cache() if the
device has a write cache or check the "emulate_write_cache" attribute
otherwise.
Reported-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NChristophe Vu-Brugier <cvubrugier@fastmail.fm>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch fixes a NULL pointer dereference triggered by a late
target_configure_device() -> alloc_workqueue() failure that results
in target_free_device() being called with DF_CONFIGURED already set,
which subsequently OOPses in destroy_workqueue() code.

Currently this only happens at modprobe target_core_mod time when
core_dev_setup_virtual_lun0() -> target_configure_device() fails,
and the explicit target_free_device() gets called.

To address this bug originally introduced by commit 0fd97ccf, go
ahead and move DF_CONFIGURED to end of target_configure_device()
code to handle this special failure case.
Reported-by: NClaudio Fleiner <cmf@daterainc.com>
Cc: Claudio Fleiner <cmf@daterainc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <stable@vger.kernel.org> # v3.7+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch fixes a NULL pointer dereference OOPs with pSCSI backends
within target_core_stat.c code.  The bug is caused by a configfs attr
read if no pscsi_dev_virt->pdv_sd has been configured.
Reported-by: NOlaf Hering <olaf@aepfle.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch adds a missing set of conditional check braces in
ft_invl_hw_context() originally introduced by commit dcd998cc
when handling DDP failures in ft_recv_write_data() code.

 commit dcd998cc
 Author: Kiran Patil <kiran.patil@intel.com>
 Date:   Wed Aug 3 09:20:01 2011 +0000

    tcm_fc: Handle DDP/SW fc_frame_payload_get failures in ft_recv_write_data
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: Kiran Patil <kiran.patil@intel.com>
Cc: <stable@vger.kernel.org> # 3.1+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch fixes a se_cmd->cmd_kref leak buf when se_sess->sess_tearing_down
is true within target_get_sess_cmd() submission path code.

This se_cmd reference leak can occur during active session shutdown when
ack_kref=1 is passed by target_submit_cmd_[map_sgls,tmr]() callers.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: <stable@vger.kernel.org> # 3.6+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch changes loopback, usb-gadget, vhost-scsi and xen-scsiback
fabric code to invoke transport_register_session() instead of the
unprotected flavour, to ensure se_tpg->session_lock is taken when
adding new session list nodes to se_tpg->tpg_sess_list.

Note that since these four fabric drivers already hold their own
internal TPG mutexes when accessing se_tpg->tpg_sess_list, and
consist of a single se_session created through configfs attribute
access, no list corruption can currently occur.

So for correctness sake, go ahead and use the se_tpg->session_lock
protected version for these four fabric drivers.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch fixes the incorrect use of __transport_register_session()
in tcm_qla2xxx_check_initiator_node_acl() code, that does not perform
explicit se_tpg->session_lock when accessing se_tpg->tpg_sess_list
to add new se_sess nodes.

Given that tcm_qla2xxx_check_initiator_node_acl() is not called with
qla_hw->hardware_lock held for all accesses of ->tpg_sess_list, the
code should be using transport_register_session() instead.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Giridhar Malavali <giridhar.malavali@qlogic.com>
Cc: Quinn Tran <quinn.tran@qlogic.com>
Cc: <stable@vger.kernel.org> # 3.5+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch fixes a iser specific logout bug where early complete()
of conn->conn_logout_comp in iscsit_close_connection() was causing
isert_wait4logout() to complete too soon, triggering a use after
free NULL pointer dereference of iscsi_conn memory.

The complete() was originally added for traditional iscsi-target
when a ISCSI_LOGOUT_OP failed in iscsi_target_rx_opcode(), but given
iser-target does not wait in logout failure, this special case needs
to be avoided.
Reported-by: NSagi Grimberg <sagig@mellanox.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Slava Shwartsman <valyushash@gmail.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This reverts commit 72859d91.

The original patch was wrong, iscsit_close_connection() still needs
to release iscsi_conn during both normal + exception IN_LOGOUT status
with ib_isert enabled.

The original OOPs is due to completing conn_logout_comp early within
iscsit_close_connection(), causing isert_wait4logout() to complete
instead of waiting for iscsit_logout_post_handler_*() to be called.
Reported-by: NSagi Grimberg <sagig@mellanox.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Slava Shwartsman <valyushash@gmail.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>