If a request is dequeued, the transfer is cancelled. Give back all
the started requests.

In most scenarios, the function driver dequeues all requests of a
transfer when there's a failure. If the function driver follows this,
then it's fine. If not, then we'd be skipping TRBs at different points
within the dequeue and enqueue pointers, making dequeue/enqueue pointers
useless. To enforce and make sure that we're properly skipping TRBs,
cancel all the started requests and give back all the cancelled requests
to the function drivers.
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

DWC3 must not issue CLEAR_STALL command to control endpoints. The
controller automatically clears the STALL when it receives the SETUP
token. Also, when the driver receives ClearFeature(halt_ep), DWC3 must
stop any active transfer from the endpoint and give back all the
requests to the function drivers.

Fixes: 72246da4 ("usb: Introduce DesignWare USB3 DRD Driver")
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

Update device tree binding document for aspeed vhub's device IDs and
string properties.
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

This patch moves patch-usb1-dev-desc logic from get-descriptor handler
to "ast_vhub_fixup_usb1_dev_desc" function so the code is executed only
once (at vhub initial time).
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

The patch overrides idVendor, idProduct and bcdDevice fields in vhub
Device Descriptor if according device tree properties are defined.
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

If "vhub,string-descriptor" device tree property is defined, the driver
will load string descriptors from device tree; otherwise, the default
string descriptors will be used.
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

The USB LANGID validation code in "check_user_usb_string" function is
moved to "usb_validate_langid" function which can be used by other usb
gadget drivers.
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

This patch introduces a link list to store string descriptors with
different languages, and "ast_vhub_rep_string" function is also improved
to support multiple language usb strings.
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

This patch evaluates vhub ports' irq mask before going through per-port
irq handling one by one, which helps to speed up irq handling in case
there is no port interrupt.
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

The DRD module calls dwc3_set_mode() on role switches, i.e. when a device is
being plugged in. In order to support continuous runtime power management when
plugging in / unplugging a cable, we need to call pm_runtime_get_sync() in
this path.
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

Mark all local functions static to fix sparse warnings.
Signed-off-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

This patch corrects the SPDX License Identifier style in
header files related to DesignWare USB2 DRD Core Support.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used).

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

This patch corrects the SPDX License Identifier style in
header files related to DesignWare USB3 DRD Core Support.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used).

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

This patch corrects the SPDX License Identifier style in
header files related to USB peripheral controller drivers.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used).

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

Pull more btrfs fixes from David Sterba:
 "A few more stability fixes, minor build warning fixes and git url
  fixup:

   - fix partial loss of prealloc extent past i_size after fsync

   - fix potential deadlock due to wrong transaction handle passing via
     journal_info

   - fix gcc 4.8 struct intialization warning

   - update git URL in MAINTAINERS entry"

* tag 'for-5.7-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  MAINTAINERS: btrfs: fix git repo URL
  btrfs: fix gcc-4.8 build warning for struct initializer
  btrfs: transaction: Avoid deadlock due to bad initialization timing of fs_info::journal_info
  btrfs: fix partial loss of prealloc extent past i_size after fsync

Pull IOMMU fixes from Joerg Roedel:

 - Fix a memory leak when dev_iommu gets freed and a sub-pointer does
   not

 - Build dependency fixes for Mediatek, spapr_tce, and Intel IOMMU
   driver

 - Export iommu_group_get_for_dev() only for GPLed modules

 - Fix AMD IOMMU interrupt remapping when x2apic is enabled

 - Fix error path in the QCOM IOMMU driver probe function

* tag 'iommu-fixes-v5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/qcom: Fix local_base status check
  iommu: Properly export iommu_group_get_for_dev()
  iommu/vt-d: Use right Kconfig option name
  iommu/amd: Fix legacy interrupt remapping for x2APIC-enabled system
  iommu: spapr_tce: Disable compile testing to fix build on book3s_32 config
  iommu/mediatek: Fix MTK_IOMMU dependencies
  iommu: Fix the memory leak in dev_iommu_free()

The git repo listed for btrfs hasn't been updated in over a year.
List the current one instead.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Pull power management fixes from Rafael Wysocki:

 - prevent the intel_pstate driver from printing excessive diagnostic
   messages in some cases (Chris Wilson)

 - make the hibernation restore kernel freeze kernel threads as well as
   user space tasks (Dexuan Cui)

 - fix the ACPI device PM disagnostic messages to include the correct
   power state name (Kai-Heng Feng).

* tag 'pm-5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM: ACPI: Output correct message on target power state
  PM: hibernate: Freeze kernel threads in software_resume()
  cpufreq: intel_pstate: Only mention the BIOS disabling turbo mode once

* pm-cpufreq:
  cpufreq: intel_pstate: Only mention the BIOS disabling turbo mode once

* pm-sleep:
  PM: hibernate: Freeze kernel threads in software_resume()

Pull iomap fix from Darrick Wong:
 "Hoist the check for an unrepresentable FIBMAP return value into
  ioctl_fibmap.

  The internal kernel function can handle 64-bit values (and is needed
  to fix a regression on ext4 + jbd2). It is only the userspace ioctl
  that is so old that it cannot deal"

* tag 'iomap-5.7-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  fibmap: Warn and return an error in case of block > INT_MAX

Pull NFS client bugfixes from Trond Myklebust:
 "Highlights include:

  Stable fixes:
   - fix handling of backchannel binding in BIND_CONN_TO_SESSION

  Bugfixes:
   - Fix a credential use-after-free issue in pnfs_roc()
   - Fix potential posix_acl refcnt leak in nfs3_set_acl
   - defer slow parts of rpc_free_client() to a workqueue
   - Fix an Oopsable race in __nfs_list_for_each_server()
   - Fix trace point use-after-free race
   - Regression: the RDMA client no longer responds to server disconnect
     requests
   - Fix return values of xdr_stream_encode_item_{present, absent}
   - _pnfs_return_layout() must always wait for layoutreturn completion

  Cleanups:
   - Remove unreachable error conditions"

* tag 'nfs-for-5.7-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFS: Fix a race in __nfs_list_for_each_server()
  NFSv4.1: fix handling of backchannel binding in BIND_CONN_TO_SESSION
  SUNRPC: defer slow parts of rpc_free_client() to a workqueue.
  NFSv4: Remove unreachable error condition due to rpc_run_task()
  SUNRPC: Remove unreachable error condition
  xprtrdma: Fix use of xdr_stream_encode_item_{present, absent}
  xprtrdma: Fix trace point use-after-free race
  xprtrdma: Restore wake-up-all to rpcrdma_cm_event_handler()
  nfs: Fix potential posix_acl refcnt leak in nfs3_set_acl
  NFS/pnfs: Fix a credential use-after-free issue in pnfs_roc()
  NFS/pnfs: Ensure that _pnfs_return_layout() waits for layoutreturn completion

Pull dmaengine fixes from Vinod Koul:
 "Core:
   - Documentation typo fixes
   - fix the channel indexes
   - dmatest: fixes for process hang and iterations

  Drivers:
   - hisilicon: build error fix without PCI_MSI
   - ti-k3: deadlock fix
   - uniphier-xdmac: fix for reg region
   - pch: fix data race
   - tegra: fix clock state"

* tag 'dmaengine-fix-5.7-rc4' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: dmatest: Fix process hang when reading 'wait' parameter
  dmaengine: dmatest: Fix iteration non-stop logic
  dmaengine: tegra-apb: Ensure that clock is enabled during of DMA synchronization
  dmaengine: fix channel index enumeration
  dmaengine: mmp_tdma: Reset channel error on release
  dmaengine: mmp_tdma: Do not ignore slave config validation errors
  dmaengine: pch_dma.c: Avoid data race between probe and irq handler
  dt-bindings: dma: uniphier-xdmac: switch to single reg region
  include/linux/dmaengine: Typos fixes in API documentation
  dmaengine: xilinx_dma: Add missing check for empty list
  dmaengine: ti: k3-psil: fix deadlock on error path
  dmaengine: hisilicon: Fix build error without PCI_MSI

Pull VFIO fixes from Alex Williamson:

 - copy_*_user validity check for new vfio_dma_rw interface (Yan Zhao)

 - Fix a potential math overflow (Yan Zhao)

 - Use follow_pfn() for calculating PFNMAPs (Sean Christopherson)

* tag 'vfio-v5.7-rc4' of git://github.com/awilliam/linux-vfio:
  vfio/type1: Fix VA->PA translation for PFNMAP VMAs in vaddr_get_pfn()
  vfio: avoid possible overflow in vfio_iommu_type1_pin_pages
  vfio: checking of validity of user vaddr in vfio_dma_rw

Pull arm64 fix from Catalin Marinas:
 "Add -fasynchronous-unwind-tables to the vDSO CFLAGS"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: vdso: Add -fasynchronous-unwind-tables to cflags

Pull io_uring fixes from Jens Axboe:

 - Fix for statx not grabbing the file table, making AT_EMPTY_PATH fail

 - Cover a few cases where async poll can handle retry, eliminating the
   need for an async thread

 - fallback request busy/free fix (Bijan)

 - syzbot reported SQPOLL thread exit fix for non-preempt (Xiaoguang)

 - Fix extra put of req for sync_file_range (Pavel)

 - Always punt splice async. We'll improve this for 5.8, but wanted to
   eliminate the inode mutex lock from the non-blocking path for 5.7
   (Pavel)

* tag 'io_uring-5.7-2020-05-01' of git://git.kernel.dk/linux-block:
  io_uring: punt splice async because of inode mutex
  io_uring: check non-sync defer_list carefully
  io_uring: fix extra put in sync_file_range()
  io_uring: use cond_resched() in io_ring_ctx_wait_and_kill()
  io_uring: use proper references for fallback_req locking
  io_uring: only force async punt if poll based retry can't handle it
  io_uring: enable poll retry for any file with ->read_iter / ->write_iter
  io_uring: statx must grab the file table for valid fd

Pull block fixes from Jens Axboe:
 "A few fixes for this release:

   - NVMe pull request from Christoph, with a single fix for a double
     free in the namespace error handling.

   - Kill the bd_openers check in blk_drop_partitions(), fixing a
     regression in this merge window (Christoph)"

* tag 'block-5.7-2020-05-01' of git://git.kernel.dk/linux-block:
  block: remove the bd_openers checks in blk_drop_partitions
  nvme: prevent double free in nvme_alloc_ns() error handling

Pull i2c fixes from Wolfram Sang:
 "Three driver bugfixes, and two reverts because the original patches
  revealed underlying problems which the Tegra guys are now working on"

* 'i2c/for-current-fixed' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: aspeed: Avoid i2c interrupt status clear race condition.
  i2c: amd-mp2-pci: Fix Oops in amd_mp2_pci_init() error handling
  Revert "i2c: tegra: Better handle case where CPU0 is busy for a long time"
  Revert "i2c: tegra: Synchronize DMA before termination"
  i2c: iproc: generate stop event for slave writes

Pull sound fixes from Takashi Iwai:
 "Just a collection of small fixes around this time:

   - One more try for fixing PCM OSS regression

   - HD-audio: a new quirk for Lenovo, the improved driver blacklisting,
     a lock fix in the minor error path, and a fix for the possible race
     at monitor notifiaction

   - USB-audio: a quirk ID fix, a fix for POD HD500 workaround"

* tag 'sound-5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: usb-audio: Correct a typo of NuPrime DAC-10 USB ID
  ALSA: opti9xx: shut up gcc-10 range warning
  ALSA: hda/hdmi: fix without unlocked before return
  ALSA: hda/hdmi: fix race in monitor detection during probe
  ALSA: hda/realtek - Two front mics on a Lenovo ThinkCenter
  ALSA: line6: Fix POD HD500 audio playback
  ALSA: pcm: oss: Place the plugin buffer overflow checks correctly (for 5.7)
  ALSA: pcm: oss: Place the plugin buffer overflow checks correctly
  ALSA: hda: Match both PCI ID and SSID for driver blacklist

Pull drm fixes from Dave Airlie:
 "Regular scheduled fixes for graphics. Nothing to extreme bunch of
  amdgpu fixes, i915 and qxl fixes, along with some misc ones.

  All seems to be progressing normally.

  core:
   - EDID off by one DTD fix
   - DP mst write return code fix

  dma-buf:
   - fix SET_NAME ioctl uapi
   - doc fixes

  amdgpu:
   - Fix a green screen on resume issue
   - PM fixes for SR-IOV SDMA fix for navi
   - Renoir display fixes
   - Cursor and pageflip stuttering fixes
   - Misc additional display fixes
   - (uapi) Add additional DCC tiling flags for navi1x

  i915:
   - Fix selftest refcnt leak (Xiyu)
   - Fix gem vma lock (Chris)
   - Fix gt's i915_request.timeline acquire by checking if cacheline is
     valid (Chris)
   - Fix IRQ postinistall fault masks (Matt)

  qxl:
   - use after gree fix
   - fix lost kunmap
   - release leak fix

  virtio:
   - context destruction fix"

* tag 'drm-fixes-2020-05-01' of git://anongit.freedesktop.org/drm/drm: (26 commits)
  dma-buf: fix documentation build warnings
  drm/qxl: qxl_release use after free
  drm/qxl: lost qxl_bo_kunmap_atomic_page in qxl_image_init_helper()
  drm/i915: Use proper fault mask in interrupt postinstall too
  drm/amd/display: Use cursor locking to prevent flip delays
  drm/amd/display: Update downspread percent to match spreadsheet for DCN2.1
  drm/amd/display: Defer cursor update around VUPDATE for all ASIC
  drm/amd/display: fix rn soc bb update
  drm/amd/display: check if REFCLK_CNTL register is present
  drm/amdgpu: bump version for invalidate L2 before SDMA IBs
  drm/amdgpu: invalidate L2 before SDMA IBs (v2)
  drm/amdgpu: add tiling flags from Mesa
  drm/amd/powerplay: avoid using pm_en before it is initialized revised
  Revert "drm/amd/powerplay: avoid using pm_en before it is initialized"
  drm/qxl: qxl_release leak in qxl_hw_surface_alloc()
  drm/qxl: qxl_release leak in qxl_draw_dirty_fb()
  drm/virtio: only destroy created contexts
  drm/dp_mst: Fix drm_dp_send_dpcd_write() return code
  drm/i915/gt: Check cacheline is valid before acquiring
  drm/i915/gem: Hold obj->vma.lock over for_each_ggtt_vma()
  ...

Pull SCSI fixes from James Bottomley:
 "Four minor fixes: three in drivers and one in the core.

  The core one allows an additional state change that fixes a regression
  introduced by an update to the aacraid driver in the previous merge
  window"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: target/iblock: fix WRITE SAME zeroing
  scsi: qla2xxx: check UNLOADING before posting async work
  scsi: qla2xxx: set UNLOADING before waiting for session deletion
  scsi: core: Allow the state change from SDEV_QUIESCE to SDEV_BLOCK

Nonblocking do_splice() still may wait for some time on an inode mutex.
Let's play safe and always punt it async.
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_req_defer() do double-checked locking. Use proper helpers for that,
i.e. list_empty_careful().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

[   40.179474] refcount_t: underflow; use-after-free.
[   40.179499] WARNING: CPU: 6 PID: 1848 at lib/refcount.c:28 refcount_warn_saturate+0xae/0xf0
...
[   40.179612] RIP: 0010:refcount_warn_saturate+0xae/0xf0
[   40.179617] Code: 28 44 0a 01 01 e8 d7 01 c2 ff 0f 0b 5d c3 80 3d 15 44 0a 01 00 75 91 48 c7 c7 b8 f5 75 be c6 05 05 44 0a 01 01 e8 b7 01 c2 ff <0f> 0b 5d c3 80 3d f3 43 0a 01 00 0f 85 6d ff ff ff 48 c7 c7 10 f6
[   40.179619] RSP: 0018:ffffb252423ebe18 EFLAGS: 00010286
[   40.179623] RAX: 0000000000000000 RBX: ffff98d65e929400 RCX: 0000000000000000
[   40.179625] RDX: 0000000000000001 RSI: 0000000000000086 RDI: 00000000ffffffff
[   40.179627] RBP: ffffb252423ebe18 R08: 0000000000000001 R09: 000000000000055d
[   40.179629] R10: 0000000000000c8c R11: 0000000000000001 R12: 0000000000000000
[   40.179631] R13: ffff98d68c434400 R14: ffff98d6a9cbaa20 R15: ffff98d6a609ccb8
[   40.179634] FS:  0000000000000000(0000) GS:ffff98d6af580000(0000) knlGS:0000000000000000
[   40.179636] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   40.179638] CR2: 00000000033e3194 CR3: 000000006480a003 CR4: 00000000003606e0
[   40.179641] Call Trace:
[   40.179652]  io_put_req+0x36/0x40
[   40.179657]  io_free_work+0x15/0x20
[   40.179661]  io_worker_handle_work+0x2f5/0x480
[   40.179667]  io_wqe_worker+0x2a9/0x360
[   40.179674]  ? _raw_spin_unlock_irqrestore+0x24/0x40
[   40.179681]  kthread+0x12c/0x170
[   40.179685]  ? io_worker_handle_work+0x480/0x480
[   40.179690]  ? kthread_park+0x90/0x90
[   40.179695]  ret_from_fork+0x35/0x40
[   40.179702] ---[ end trace 85027405f00110aa ]---

Opcode handler must never put submission ref, but that's what
io_sync_file_range_finish() do. use io_steal_work() there.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The function qcom_iommu_device_probe() does not perform sufficient
error checking after executing devm_ioremap_resource(), which can
result in crashes if a critical error path is encountered.

Fixes: 0ae349a0 ("iommu/qcom: Add qcom_iommu")
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20200418134703.1760-1-tangbin@cmss.chinamobile.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

In commit a7ba5c3d ("drivers/iommu: Export core IOMMU API symbols to
permit modular drivers") a bunch of iommu symbols were exported, all
with _GPL markings except iommu_group_get_for_dev().  That export should
also be _GPL like the others.

Fixes: a7ba5c3d ("drivers/iommu: Export core IOMMU API symbols to permit modular drivers")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: John Garry <john.garry@huawei.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200430120120.2948448-1-gregkh@linuxfoundation.orgSigned-off-by: Joerg Roedel <jroedel@suse.de>

The CONFIG_ prefix should be added in the code.

Fixes: 04618252 ("iommu/vt-d: Add Kconfig option to enable/disable scalable mode")
Reported-and-tested-by: Kumar, Sanjay K <sanjay.k.kumar@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Link: https://lore.kernel.org/r/20200501072427.14265-1-baolu.lu@linux.intel.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

Currently, system fails to boot because the legacy interrupt remapping
mode does not enable 128-bit IRTE (GA), which is required for x2APIC
support.

Fix by using AMD_IOMMU_GUEST_IR_LEGACY_GA mode when booting with
kernel option amd_iommu_intr=legacy instead. The initialization
logic will check GASup and automatically fallback to using
AMD_IOMMU_GUEST_IR_LEGACY if GA mode is not supported.

Fixes: 3928aa3f ("iommu/amd: Detect and enable guest vAPIC support")
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Link: https://lore.kernel.org/r/1587562202-14183-1-git-send-email-suravee.suthikulpanit@amd.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

While working on to make io_uring sqpoll mode support syscalls that need
struct files_struct, I got cpu soft lockup in io_ring_ctx_wait_and_kill(),

    while (ctx->sqo_thread && !wq_has_sleeper(&ctx->sqo_wait))
        cpu_relax();

above loop never has an chance to exit, it's because preempt isn't enabled
in the kernel, and the context calling io_ring_ctx_wait_and_kill() and
io_sq_thread() run in the same cpu, if io_sq_thread calls a cond_resched()
yield cpu and another context enters above loop, then io_sq_thread() will
always in runqueue and never exit.

Use cond_resched() can fix this issue.

 Reported-by: syzbot+66243bb7126c410cefe6@syzkaller.appspotmail.com
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Use ctx->fallback_req address for test_and_set_bit_lock() and
clear_bit_unlock().
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>