With current termination flow we call release_conn after completion.
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

When we receive an event that triggers connection termination,
we have a a couple of things we may want to do:
1. In case we are already terminating, bailout early
2. In case we are connected but not bound, disconnect and schedule
   a connection cleanup silently (don't reinstate)
3. In case we are connected and bound, disconnect and reinstate the connection

This rework fixes a bug that was detected against a mis-behaved
initiator which rejected our rdma_cm accept, in this stage the
isert_conn is no bound and reinstate caused a bogus dereference.

What's great about this is that we don't need the
post_recv_buf_count anymore, so get rid of it.
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

No need to restrict this check to specific events.
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

We need an indication that isert_conn->iscsi_conn binding has
happened so we'll know not to invoke a connection reinstatement
on an unbound connection which will lead to a bogus isert_conn->conn
dereferece.
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Once connection request is accepted, one rx descriptor
is posted to receive login request. This descriptor has rx type,
but is outside the main pool of rx descriptors, and thus
was mistreated as tx type.
Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

 #cat  /sys/kernel/debug/qla2xxx/qla2xxx_31/tgt_sess
 qla2xxx_31
 Port ID   Port Name                Handle
 ff:fc:01  21:fd:00:05:33:c7:ec:16  0
 01:0e:00  21:00:00:24:ff:7b:8a:e4  1
 01:0f:00  21:00:00:24:ff:7b:8a:e5  2
 ....

(Drop ->check_initiator_node_acl() parameter usage - nab)
Signed-off-by: Quinn Tran <quinn.tran@qlogic.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch converts ib_srpt to use existing percpu_ida tag
pre-allocation for struct srpt_send_ioctx.

This allows ib_srpt to drop it's internal pre-allocation
mechanisms with the extra spin_lock_irqsave, and use
percpu_ida common code for doing this.

Cc: Vu Pham <vu@mellanox.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch converts tcm_fc to modern TARGET_SCF_ACK_KREF
usage for ft_queue_status(), and fixes ft_check_stop_free()
to return transport_generic_free_cmd() for ->cmd_kref.

It also converts TM request -> ft_send_tm() to use ACK_KREF,
and update ft_queue_tm_resp() to drop the outstanding kref
after queueing TM response into fabric code.

Cc: Vasu Dev <vasu.dev@linux.intel.com>
Cc: Mark Rustad <mark.d.rustad@intel.com>
Cc: Robert Love <robert.w.love@intel.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch converts xen-scsiback to modern TARGET_SCF_ACK_KREF
usage for scsiback_cmd_done() callback path.

It also also converts TMR -> scsiback_device_action() to use
modern target_submit_tmr() code.
Acked-by: Juergen Gross <jgross@suse.com>
Tested-by: Juergen Gross <jgross@suse.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch converts xen-scsiback to use percpu_ida tag
pre-allocation for struct vscsibk_pend descriptor, in
order to avoid fast-path struct vscsibk_pend memory
allocations.

Note by default this is currently hardcoded to 128.

(Add wrapper for handling pending_req tag failure - Juergen)
(Drop left-over se_cmd memset in scsiback_cmd_exec - Juergen)
Acked-by: Juergen Gross <jgross@suse.com>
Tested-by: Juergen Gross <jgross@suse.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch drops struct usbg_cmd->kref internal kref-erence
usage, for proper TARGET_SCF_ACK_KREF conversion.
Tested-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch converts usb-gadget target to use percpu_ida tag
pre-allocation for struct usbg_cmd descriptor, in order to
avoid fast-path struct usbg_cmd memory allocations.

Note by default this is currently hardcoded to 128.
Tested-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch converts sbp-target to modern TARGET_SCF_ACK_KREF
usage for sbp_send_status() callback path, and drops the now
obsolete sbp_free_request() failure path calls.
Acked-by: Chris Boot <bootc@bootc.net>
Tested-by: Chris Boot <bootc@bootc.net>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch converts sbp-target to use struct sbp_target_request
descriptor tag pre-allocation using percpu_ida.

(Fix sbp_mgt_get_req() IS_ERR failure checking - Dan Carpenter)
(Add missing sbp_target_request tag memset - Chris Boot)
Acked-by: Chris Boot <bootc@bootc.net>
Tested-by: Chris Boot <bootc@bootc.net>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch converts ib_srpt internal assignments of
se_node_acl and transport_register_session() to use
the new alloc_session method.

Cc: Vu Pham <vu@mellanox.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch converts tcm_fc target mode addition of tf_sess->hash to
port_id hlist_head using the new alloc_session callback().

Cc: Vasu Dev <vasu.dev@linux.intel.com>
Cc: Mark Rustad <mark.d.rustad@intel.com>
Cc: Robert Love <robert.w.love@intel.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch converts existing qla2xxx target mode assignment
of struct qla_tgt_sess related sid + loop_id values to use
a callback via the new target_alloc_session API caller.

Cc: Himanshu Madhani <himanshu.madhani@qlogic.com>
Cc: Quinn Tran <quinn.tran@qlogic.com>
Cc: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch converts vhost/scsi pre-allocation of vhost_scsi_cmd
descriptors to use the new alloc_session callback().
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch converts existing loopback, usb-gadget, and
xen-scsiback demo-mode only fabric drivers to use the
new target_alloc_session API caller.

This includes adding a new alloc_session callback for
fabric driver internal nexus pointer assignments.

(Fixes for early for-next nexus breakage - Dan Carpenter)

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Acked-by: Juergen Gross <jgross@suse.com>
Tested-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Tested-by: Chris Boot <bootc@bootc.net>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Based on HCH's original patch, this adds a full version to
support percpu-ida tag pre-allocation and callback function
pointer into fabric driver code to complete session setup.
Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Pull x86 fixes from Ingo Molnar:
 "This is unusually large, partly due to the EFI fixes that prevent
  accidental deletion of EFI variables through efivarfs that may brick
  machines.  These fixes are somewhat involved to maintain compatibility
  with existing install methods and other usage modes, while trying to
  turn off the 'rm -rf' bricking vector.

  Other fixes are for large page ioremap()s and for non-temporal
  user-memcpy()s"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Fix vmalloc_fault() to handle large pages properly
  hpet: Drop stale URLs
  x86/uaccess/64: Handle the caching of 4-byte nocache copies properly in __copy_user_nocache()
  x86/uaccess/64: Make the __copy_user_nocache() assembly code more readable
  lib/ucs2_string: Correct ucs2 -> utf8 conversion
  efi: Add pstore variables to the deletion whitelist
  efi: Make efivarfs entries immutable by default
  efi: Make our variable validation list include the guid
  efi: Do variable name validation tests in utf8
  efi: Use ucs2_as_utf8 in efivarfs instead of open coding a bad version
  lib/ucs2_string: Add ucs2 -> utf8 helper functions

Pull perf fixes from Ingo Molnar:
 "A handful of CPU hotplug related fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Plug potential memory leak in CPU_UP_PREPARE
  perf/core: Remove the bogus and dangerous CPU_DOWN_FAILED hotplug state
  perf/core: Remove bogus UP_CANCELED hotplug state
  perf/x86/amd/uncore: Plug reference leak

Pull powerpc fixes from Michael Ellerman:
 - Fix build error on 32-bit with checkpoint restart from Aneesh Kumar
 - Fix dedotify for binutils >= 2.26 from Andreas Schwab
 - Don't trace hcalls on offline CPUs from Denis Kirjanov
 - eeh: Fix stale cached primary bus from Gavin Shan
 - eeh: Fix stale PE primary bus from Gavin Shan
 - mm: Fix Multi hit ERAT cause by recent THP update from Aneesh Kumar K.V
 - ioda: Set "read" permission when "write" is set from Alexey Kardashevskiy

* tag 'powerpc-4.5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/ioda: Set "read" permission when "write" is set
  powerpc/mm: Fix Multi hit ERAT cause by recent THP update
  powerpc/powernv: Fix stale PE primary bus
  powerpc/eeh: Fix stale cached primary bus
  powerpc/pseries: Don't trace hcalls on offline CPUs
  powerpc: Fix dedotify for binutils >= 2.26
  powerpc/book3s_32: Fix build error with checkpoint restart

Pull dmaengine fixes from Vinod Koul:
 "A few fixes for drivers, nothing major here.

  Fixes are: iotdma fix to restart channels, new ID for wildcat PCH,
  residue fix for edma, disable irq for non-cyclic in dw"

* tag 'dmaengine-fix-4.5-rc5' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: dw: disable BLOCK IRQs for non-cyclic xfer
  dmaengine: edma: fix residue race for cyclic
  dmaengine: dw: pci: add ID for WildcatPoint PCH
  dmaengine: IOATDMA: fix timer code that continues to restart channels during idle

Pull clk driver fixes from Stephen Boyd:
 "An assortment of vendor specific clk drivers fixes, most notably
  fallout from adding Tegra210 and rockchip rk3036/rk3368 drivers this
  cycle.

  There's also the random smattering of sparse/checker fixes, a build
  "fix" to get the Tango clk driver to compile because the Kconfig
  symbol was renamed after the fact, and a clk gpio fix for a patch
  mismerge"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: (28 commits)
  clk: gpio: Really allow an optional clock= DT property
  Revert "clk: qcom: Specify LE device endianness"
  clk: versatile: mask VCO bits before writing
  clk: tegra: super: Fix sparse warnings for functions not declared as static
  clk: tegra: Fix sparse warnings for functions not declared as static
  clk: tegra: Fix sparse warning for pll_m
  clk: tegra: Use definition for pll_u override bit
  clk: tegra: Fix warning caused by pll_u failing to lock
  clk: tegra: Fix clock sources for Tegra210 EMC
  clk: tegra: Add the APB2APE audio clock on Tegra210
  clk: tegra: Add missing of_node_put()
  clk: tegra: Fix PLLE SS coefficients
  clk: tegra: Fix typos around clearing PLLE bits during enable
  clk: tegra: Do not disable PLLE when under hardware control
  clk: tegra: Fix pllx dyn step calculation
  clk: tegra: pll: Fix potential sleeping-while-atomic
  clk: tegra: Fix the misnaming of nvenc from msenc
  clk: tegra: Fix naming of MISC registers
  clk: tango4: rename ARCH_TANGOX to ARCH_TANGO
  clk: scpi: Fix checking return value of platform_device_register_simple()
  ...

Pull more drm fixes from Dave Airlie:
 "Some more fixes trickled in:

  A bunch of VC4 ones since it's a pretty new driver not much chance of
  regressions, and it fixes GPU resets.

  Also one atomic fix, one set of fixes for a common bug in TTM cleanup,
  and one i915 hotplug fix"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/nouveau: use post-decrement in error handling
  drm/atomic: Allow for holes in connector state, v2.
  drm/i915: Fix hpd live status bits for g4x
  drm/vc4: Use runtime PM to power cycle the device when the GPU hangs.
  drm/vc4: Enable runtime PM.
  drm/vc4: Fix spurious GPU resets due to BO reuse.
  drm/vc4: Drop error message on seqno wait timeouts.
  drm/vc4: Fix -ERESTARTSYS error return from BO waits.
  drm/vc4: Return an ERR_PTR from BO creation instead of NULL.
  drm/vc4: Fix the clear color for the first tile rendered.
  drm/vc4: Validate that WAIT_BO padding is cleared.
  drm/radeon: use post-decrement in error handling
  drm/amdgpu: use post-decrement in error handling

In __request_region, if a conflict with a BUSY and MUXED resource is
detected, then the caller goes to sleep and waits for the resource to be
released.  A pointer on the conflicting resource is kept.  At wake-up
this pointer is used as a parent to retry to request the region.

A first problem is that this pointer might well be invalid (if for
example the conflicting resource have already been freed).  Another
problem is that the next call to __request_region() fails to detect a
remaining conflict.  The previously conflicting resource is passed as a
parameter and __request_region() will look for a conflict among the
children of this resource and not at the resource itself.  It is likely
to succeed anyway, even if there is still a conflict.

Instead, the parent of the conflicting resource should be passed to
__request_region().

As a fix, this patch doesn't update the parent resource pointer in the
case we have to wait for a muxed region right after.
Reported-and-tested-by: Vincent Pelletier <plr.vincent@gmail.com>
Signed-off-by: Simon Guinot <simon.guinot@sequanux.org>
Tested-by: Vincent Donnefort <vdonnefort@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull ext4 bugfixes from Ted Ts'o:
 "Miscellaneous ext4 bug fixes for v4.5"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: fix crashes in dioread_nolock mode
  ext4: fix bh->b_state corruption
  ext4: fix memleak in ext4_readdir()
  ext4: remove unused parameter "newblock" in convert_initialized_extent()
  ext4: don't read blocks from disk after extents being swapped
  ext4: fix potential integer overflow
  ext4: add a line break for proc mb_groups display
  ext4: ioctl: fix erroneous return value
  ext4: fix scheduling in atomic on group checksum failure
  ext4 crypto: move context consistency check to ext4_file_open()
  ext4 crypto: revalidate dentry after adding or removing the key

Pull btrfs fix from Chris Mason:
 "My for-linus-4.5 branch has a btrfs DIO error passing fix.

  I know how much you love DIO, so I'm going to suggest against reading
  it.  We'll follow up with a patch to drop the error arg from
  dio_end_io in the next merge window."

* 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix direct IO requests not reporting IO error to user space

Merge fixes from Andrew Morton:
 "10 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm: slab: free kmem_cache_node after destroy sysfs file
  ipc/shm: handle removed segments gracefully in shm_mmap()
  MAINTAINERS: update Kselftest Framework mailing list
  devm_memremap_release(): fix memremap'd addr handling
  mm/hugetlb.c: fix incorrect proc nr_hugepages value
  mm, x86: fix pte_page() crash in gup_pte_range()
  fsnotify: turn fsnotify reaper thread into a workqueue job
  Revert "fsnotify: destroy marks with call_srcu instead of dedicated thread"
  mm: fix regression in remap_file_pages() emulation
  thp, dax: do not try to withdraw pgtable from non-anon VMA

Pull arm64 fixes from Will Deacon:
 "Here are some more arm64 fixes for 4.5.  This has mostly come from
  Yang Shi, who saw some issues under -rt that also affect mainline.
  The rest of it is pretty small, but still worth having.

  We've got an old issue outstanding with valid_user_regs which will
  likely wait until 4.6 (since it would really benefit from some time in
  -next) and another issue with kasan and idle which should be fixed
  next week.

  Apart from that, pretty quiet here (and still no sign of the THP issue
  reported on s390...)

  Summary:

   - Allow EFI stub to use strnlen(), which is required by recent libfdt

   - Avoid smp_processor_id() in preempt context during unwinding

   - Avoid false Kasan warnings during unwinding

   - Ensure early devices are picked up by the IOMMU DMA ops

   - Avoid rebuilding the kernel for the 'install' target

   - Run fixup handlers for alignment faults on userspace access"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: mm: allow the kernel to handle alignment faults on user accesses
  arm64: kbuild: make "make install" not depend on vmlinux
  arm64: dma-mapping: fix handling of devices registered before arch_initcall
  arm64/efi: Make strnlen() available to the EFI namespace
  arm/arm64: crypto: assure that ECB modes don't require an IV
  arm64: make irq_stack_ptr more robust
  arm64: debug: re-enable irqs before sending breakpoint SIGTRAP
  arm64: disable kasan when accessing frame->fp in unwind_frame

Pull s390 fixes from Martin Schwidefsky:
 "Several bug fixes:

   - There are four different stack tracers, and three of them have
     bugs.  For 4.5 the bugs are fixed and we prepare a cleanup patch
     for the next merge window.

   - Three bug fixes for the dasd driver in regard to parallel access
     volumes and the new max_dev_sectors block device queue limit

   - The irq restore optimization needs a fixup for memcpy_real

   - The diagnose trace code has a conflict with lockdep"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/dasd: fix performance drop
  s390/maccess: reduce stnsm instructions
  s390/diag: avoid lockdep recursion
  s390/dasd: fix refcount for PAV reassignment
  s390/dasd: prevent incorrect length error under z/VM after PAV changes
  s390: fix DAT off memory access, e.g. on kdump
  s390/oprofile: fix address range for asynchronous stack
  s390/perf_event: fix address range for asynchronous stack
  s390/stacktrace: add save_stack_trace_regs()
  s390/stacktrace: save full stack traces
  s390/stacktrace: add missing end marker
  s390/stacktrace: fix address ranges for asynchronous and panic stack
  s390/stacktrace: fix save_stack_trace_tsk() for current task

Pull Pin control fixes from Linus Walleij:
 "Pin control fixes for the v4.5 series, all are individual driver
  fixes:

   - Fix the PXA2xx driver to export its init function so we do not
     break modular compiles.
   - Hide unused functions in the Nomadik driver.
   - Fix up direction control in the Mediatek driver.
   - Toggle the sunxi GPIO lines to input when you read them on the H3
     GPIO controller, lest you only get garbage.
   - Fix up the number of settings in the MVEBU driver.
   - Fix a serious SMP race condition in the Samsung driver"

* tag 'pinctrl-v4.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  pinctrl: samsung: fix SMP race condition
  pinctrl: mvebu: fix num_settings in mpp group assignment
  pinctrl: sunxi: H3 requires irq_read_needs_mux
  pinctrl: mediatek: fix direction control issue
  pinctrl: nomadik: hide unused functions
  pinctrl: pxa: export pxa2xx_pinctrl_init()

Pull sound fixes from Takashi Iwai:
 "This update contains again a few more fixes for ALSA core stuff
  although it's no longer high flux: two race fixes in sequencer and one
  PCM race fix for non-atomic PCM ops.

  In addition, HD-audio gained a similar fix for race at reloading the
  driver"

* tag 'sound-4.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: pcm: Fix rwsem deadlock for non-atomic PCM stream
  ALSA: seq: Fix double port list deletion
  ALSA: hda - Cancel probe work instead of flush at remove
  ALSA: seq: Fix leak of pool buffer at concurrent writes

Although we don't expect to take alignment faults on access to normal
memory, misbehaving (i.e. buggy) user code can pass MMIO pointers into
system calls, leading to things like get_user accessing device memory.

Rather than OOPS the kernel, allow any exception fixups to run and
return something like -EFAULT back to userspace. This makes the
behaviour more consistent with userspace, even though applications with
access to device mappings can easily cause other issues if they try
hard enough.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Eun Taik Lee <eun.taik.lee@samsung.com>
[will: dropped __kprobes annotation and rewrote commit mesage]
Signed-off-by: Will Deacon <will.deacon@arm.com>

For the same reason as commit 19514fc6 ("arm, kbuild: make "make
install" not depend on vmlinux"), the install targets should never
trigger the rebuild of the kernel.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Competing overwrite DIO in dioread_nolock mode will just overwrite
pointer to io_end in the inode. This may result in data corruption or
extent conversion happening from IO completion interrupt because we
don't properly set buffer_defer_completion() when unlocked DIO races
with locked DIO to unwritten extent.

Since unlocked DIO doesn't need io_end for anything, just avoid
allocating it and corrupting pointer from inode for locked DIO.
A cleaner fix would be to avoid these games with io_end pointer from the
inode but that requires more intrusive changes so we leave that for
later.

Cc: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4 can update bh->b_state non-atomically in _ext4_get_block() and
ext4_da_get_block_prep(). Usually this is fine since bh is just a
temporary storage for mapping information on stack but in some cases it
can be fully living bh attached to a page. In such case non-atomic
update of bh->b_state can race with an atomic update which then gets
lost. Usually when we are mapping bh and thus updating bh->b_state
non-atomically, nobody else touches the bh and so things work out fine
but there is one case to especially worry about: ext4_finish_bio() uses
BH_Uptodate_Lock on the first bh in the page to synchronize handling of
PageWriteback state. So when blocksize < pagesize, we can be atomically
modifying bh->b_state of a buffer that actually isn't under IO and thus
can race e.g. with delalloc trying to map that buffer. The result is
that we can mistakenly set / clear BH_Uptodate_Lock bit resulting in the
corruption of PageWriteback state or missed unlock of BH_Uptodate_Lock.

Fix the problem by always updating bh->b_state bits atomically.

CC: stable@vger.kernel.org
Reported-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

We need to use post-decrement to get the dma_map_page undone also for
i==0, and to avoid some very unpleasant behaviour if dma_map_page
failed already at i==0.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>