There is nothing preventing an ioctl from trying do delete partition
concurrenly with del_gendisk, so take open_mutex to serialize against
that.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210406062303.811835-6-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Move the busy check and disk-wide sync into the only caller, so that
the remainder can be shared with del_gendisk.  Also pass the gendisk
instead of the bdev as that is all that is needed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210406062303.811835-5-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Move the calls to fsync_bdev and __invalidate_device from del_gendisk to
delete_partition.  For the other two callers that check that there are
no openers for the delete partitions(s) the callouts are a no-op as no
file system can be mounted, but this keeps all the cleanup in one
place.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210406062303.811835-4-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

invalidate_partition has two callers, one of which already performs
the remove_inode_hash just after the call.  Just open code the
function in the two callsites.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210406062303.811835-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Use the more general interface - the behavior is the same except
that now a change uevent is sent, which is the right thing to do
when the device becomes unusable.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20210406062303.811835-2-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Commit e76239a3 ("block: add a report_zones method") removed the last
blk_zone_start() call. Hence also remove the definition of this function.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210406200820.15180-1-bvanassche@acm.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

Yanhui found that write performance is degraded a lot after applying
hctx shared tagset on one test machine with megaraid_sas. And turns out
it is caused by none scheduler which becomes default elevator caused by
hctx shared tagset patchset.

Given more scsi HBAs will apply hctx shared tagset, and the similar
performance exists for them too.

So keep previous behavior by still using default mq-deadline for queues
which apply hctx shared tagset, just like before.

Fixes: 32bc15af ("blk-mq: Facilitate a shared sbitmap per tagset")
Reported-by: Yanhui Ma <yama@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/20210406031933.767228-1-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Instead of overloading the passthrough fast path with the deprecated
block layer bounce buffering let the users that combine an old
undermaintained driver with a highmem system pay the price by always
falling back to copies in that case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210331073001.46776-9-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Get rid of all the PFN arithmetics and just use an enum for the two
remaining options, and use PageHighMem for the actual bounce decision.

Add a fast path to entirely avoid the call for the common case of a queue
not using the legacy bouncing code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210331073001.46776-8-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Remove the BLK_BOUNCE_ISA support now that all users are gone.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210331073001.46776-7-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Remove the unchecked_isa_dma now that all users are gone.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210331073001.46776-6-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

This is the last piece in the kernel requiring the block layer ISA
bounce buffering, and it does not actually look used.  So remove it
to see if anyone screams, in which case we'll need to find a solution
to fix it back up.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210331073001.46776-5-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Warn on and don't support adapters that have a DMA bug that forces ISA-style
bounce buffering.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Khalid Aziz <khalid@gonehiking.org>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210331073001.46776-4-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

The ISA support in Buslogic has been broken for a long time, as all
the I/O path expects a struct device for DMA mapping that is derived from
the PCI device, which would simply crash for ISA adapters.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Khalid Aziz <khalid@gonehiking.org>
Link: https://lore.kernel.org/r/20210331073001.46776-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

To remove the last user of the unchecked_isa_dma flag and thus the block
layer ISA bounce buffering switch this driver to use its own local bounce
buffer.  This has the effect of not needing the chain indirection and
supporting and unlimited number of segments.  It does however limit the
transfer size for each command to something that can be reasonable
allocated by dma_alloc_coherent like 8K.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210331073001.46776-2-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Link: https://lore.kernel.org/r/20210311081713.2763171-1-nborisov@suse.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

This entry will expose the bio vector alignment mask for a specific
block device.
Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20210405132012.12504-1-mgurtovoy@nvidia.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Many throughput-sensitive workloads are made of several parallel I/O
flows, with all flows generated by the same application, or more
generically by the same task (e.g., system boot). The most
counterproductive action with these workloads is plugging I/O dispatch
when one of the bfq_queues associated with these flows remains
temporarily empty.

To avoid this plugging, BFQ has been using a burst-handling mechanism
for years now. This mechanism has proven effective for throughput, and
not detrimental for service guarantees. This commit pushes this
mechanism a little bit further, basing on the following two facts.

First, all the I/O flows of a the same application or task contribute
to the execution/completion of that common application or task. So the
performance figures that matter are total throughput of the flows and
task-wide I/O latency.  In particular, these flows do not need to be
protected from each other, in terms of individual bandwidth or
latency.

Second, the above fact holds regardless of the number of flows.

Putting these two facts together, this commits merges stably the
bfq_queues associated with these I/O flows, i.e., with the processes
that generate these IO/ flows, regardless of how many the involved
processes are.

To decide whether a set of bfq_queues is actually associated with the
I/O flows of a common application or task, and to merge these queues
stably, this commit operates as follows: given a bfq_queue, say Q2,
currently being created, and the last bfq_queue, say Q1, created
before Q2, Q2 is merged stably with Q1 if
- very little time has elapsed since when Q1 was created
- Q2 has the same ioprio as Q1
- Q2 belongs to the same group as Q1

Merging bfq_queues also reduces scheduling overhead. A fio test with
ten random readers on /dev/nullb shows a throughput boost of 40%, with
a quadcore. Since BFQ's execution time amounts to ~50% of the total
per-request processing time, the above throughput boost implies that
BFQ's overhead is reduced by more than 50%.
Tested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Link: https://lore.kernel.org/r/20210304174627.161-7-paolo.valente@linaro.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

Shared queues are likely to receive I/O at a high rate. This may
deceptively let them be considered as wakers of other queues. But a
false waker will unjustly steal bandwidth to its supposedly woken
queue. So considering also shared queues in the waking mechanism may
cause more control troubles than throughput benefits. This commit
keeps shared queues out of the waker-detection mechanism.
Tested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Link: https://lore.kernel.org/r/20210304174627.161-6-paolo.valente@linaro.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

When the io_latency heuristic is off, bfq_queues must not start to be
weight-raised. Unfortunately, by mistake, this may happen when the
state of a previously weight-raised bfq_queue is resumed after a queue
split. This commit fixes this error.
Tested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Link: https://lore.kernel.org/r/20210304174627.161-5-paolo.valente@linaro.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

Consider a bfq_queue bfqq that is about to be merged with another
bfq_queue new_bfqq. The processes associated with bfqq are cooperators
of the processes associated with new_bfqq. So, if bfqq has a waker,
then it is reasonable (and beneficial for throughput) to assume that
all these processes will be happy to let bfqq's waker freely inject
I/O when they have no I/O. So this commit makes new_bfqq inherit
bfqq's waker.
Tested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Link: https://lore.kernel.org/r/20210304174627.161-4-paolo.valente@linaro.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

Consider a new I/O request that arrives for a bfq_queue bfqq. If, when
this happens, the only active bfq_queues are bfqq and either its waker
bfq_queue or one of its woken bfq_queues, then there is no point in
queueing this new I/O request in bfqq for service. In fact, the
in-service queue and bfqq agree on serving this new I/O request as
soon as possible. So this commit puts this new I/O request directly
into the dispatch list.
Tested-by: Jan Kara <jack@suse.cz>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Link: https://lore.kernel.org/r/20210304174627.161-3-paolo.valente@linaro.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

Suppose that I/O dispatch is plugged, to wait for new I/O for the
in-service bfq-queue, say bfqq.  Suppose then that there is a further
bfq_queue woken by bfqq, and that this woken queue has pending I/O. A
woken queue does not steal bandwidth from bfqq, because it remains
soon without I/O if bfqq is not served. So there is virtually no risk
of loss of bandwidth for bfqq if this woken queue has I/O dispatched
while bfqq is waiting for new I/O. In contrast, this extra I/O
injection boosts throughput. This commit performs this extra
injection.
Tested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Link: https://lore.kernel.org/r/20210304174627.161-2-paolo.valente@linaro.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

Sentence reconstruction for better readability.
Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull ext4 fixes from Ted Ts'o:
 "Miscellaneous ext4 bug fixes for v5.12"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: initialize ret to suppress smatch warning
  ext4: stop inode update before return
  ext4: fix rename whiteout with fast commit
  ext4: fix timer use-after-free on failed mount
  ext4: fix potential error in ext4_do_update_inode
  ext4: do not try to set xattr into ea_inode if value is empty
  ext4: do not iput inode under running transaction in ext4_rename()
  ext4: find old entry again if failed to rename whiteout
  ext4: fix error handling in ext4_end_enable_verity()
  ext4: fix bh ref count on error paths
  fs/ext4: fix integer overflow in s_log_groups_per_flex
  ext4: add reclaim checks to xattr code
  ext4: shrink race window in ext4_should_retry_alloc()

Pull io_uring followup fixes from Jens Axboe:

 - The SIGSTOP change from Eric, so we properly ignore that for
   PF_IO_WORKER threads.

 - Disallow sending signals to PF_IO_WORKER threads in general, we're
   not interested in having them funnel back to the io_uring owning
   task.

 - Stable fix from Stefan, ensuring we properly break links for short
   send/sendmsg recv/recvmsg if MSG_WAITALL is set.

 - Catch and loop when needing to run task_work before a PF_IO_WORKER
   threads goes to sleep.

* tag 'io_uring-5.12-2021-03-21' of git://git.kernel.dk/linux-block:
  io_uring: call req_set_fail_links() on short send[msg]()/recv[msg]() with MSG_WAITALL
  io-wq: ensure task is running before processing task_work
  signal: don't allow STOP on PF_IO_WORKER threads
  signal: don't allow sending any signals to PF_IO_WORKER threads

Pull staging and IIO driver fixes from Greg KH:
 "Some small staging and IIO driver fixes:

   - MAINTAINERS changes for the move of the staging mailing list

   - comedi driver fixes to get request_irq() to work correctly

   - counter driver fixes for reported issues with iio devices

   - tiny iio driver fixes for reported issues.

  All of these have been in linux-next with no reported problems"

* tag 'staging-5.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: vt665x: fix alignment constraints
  staging: comedi: cb_pcidas64: fix request_irq() warn
  staging: comedi: cb_pcidas: fix request_irq() warn
  MAINTAINERS: move the staging subsystem to lists.linux.dev
  MAINTAINERS: move some real subsystems off of the staging mailing list
  iio: gyro: mpu3050: Fix error handling in mpu3050_trigger_handler
  iio: hid-sensor-temperature: Fix issues of timestamp channel
  iio: hid-sensor-humidity: Fix alignment issue of timestamp channel
  counter: stm32-timer-cnt: fix ceiling miss-alignment with reload register
  counter: stm32-timer-cnt: fix ceiling write max value
  counter: stm32-timer-cnt: Report count function when SLAVE_MODE_DISABLED
  iio: adc: ab8500-gpadc: Fix off by 10 to 3
  iio:adc:stm32-adc: Add HAS_IOMEM dependency
  iio: adis16400: Fix an error code in adis16400_initial_setup()
  iio: adc: adi-axi-adc: add proper Kconfig dependencies
  iio: adc: ad7949: fix wrong ADC result due to incorrect bit mask
  iio: hid-sensor-prox: Fix scale not correct issue
  iio:adc:qcom-spmi-vadc: add default scale to LR_MUX2_BAT_ID channel

Pull USB and Thunderbolt driver fixes from Greg KH:
 "Here are some small Thunderbolt and USB driver fixes for some reported
  issues:

   - thunderbolt fixes for minor problems

   - typec fixes for power issues

   - usb-storage quirk addition

   - usbip bugfix

   - dwc3 bugfix when stopping transfers

   - cdnsp bugfix for isoc transfers

   - gadget use-after-free fix

  All have been in linux-next this week with no reported issues"

* tag 'usb-5.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: typec: tcpm: Skip sink_cap query only when VDM sm is busy
  usb: dwc3: gadget: Prevent EP queuing while stopping transfers
  usb: typec: tcpm: Invoke power_supply_changed for tcpm-source-psy-
  usb: typec: Remove vdo[3] part of tps6598x_rx_identity_reg struct
  usb-storage: Add quirk to defeat Kindle's automatic unload
  usb: gadget: configfs: Fix KASAN use-after-free
  usbip: Fix incorrect double assignment to udc->ud.tcp_rx
  usb: cdnsp: Fixes incorrect value in ISOC TRB
  thunderbolt: Increase runtime PM reference count on DP tunnel discovery
  thunderbolt: Initialize HopID IDAs in tb_switch_alloc()

Pull irq fix from Ingo Molnar:
 "A change to robustify force-threaded IRQ handlers to always disable
  interrupts, plus a DocBook fix.

  The force-threaded IRQ handler change has been accelerated from the
  normal schedule of such a change to keep the bad pattern/workaround of
  spin_lock_irqsave() in handlers or IRQF_NOTHREAD as a kludge from
  spreading"

* tag 'irq-urgent-2021-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Disable interrupts for force threaded handlers
  genirq/irq_sim: Fix typos in kernel doc (fnode -> fwnode)

Pull perf fixes from Ingo Molnar:
 "Boundary condition fixes for bugs unearthed by the perf fuzzer"

* tag 'perf-urgent-2021-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Fix unchecked MSR access error caused by VLBR_EVENT
  perf/x86/intel: Fix a crash caused by zero PEBS status

Pull locking fixes from Ingo Molnar:

 - Get static calls & modules right. Hopefully.

 - WW mutex fixes

* tag 'locking-urgent-2021-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  static_call: Fix static_call_update() sanity check
  static_call: Align static_call_is_init() patching condition
  static_call: Fix static_call_set_init()
  locking/ww_mutex: Fix acquire/release imbalance in ww_acquire_init()/ww_acquire_fini()
  locking/ww_mutex: Simplify use_ww_ctx & ww_ctx handling

Pull EFI fixes from Ingo Molnar:

 - another missing RT_PROP table related fix, to ensure that the
   efivarfs pseudo filesystem fails gracefully if variable services
   are unsupported

 - use the correct alignment for literal EFI GUIDs

 - fix a use after unmap issue in the memreserve code

* tag 'efi-urgent-2021-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi: use 32-bit alignment for efi_guid_t literals
  firmware/efi: Fix a use after bug in efi_mem_reserve_persistent
  efivars: respect EFI_UNSUPPORTED return from firmware

Pull x86 fixes from Borislav Petkov:
 "The freshest pile of shiny x86 fixes for 5.12:

   - Add the arch-specific mapping between physical and logical CPUs to
     fix devicetree-node lookups

   - Restore the IRQ2 ignore logic

   - Fix get_nr_restart_syscall() to return the correct restart syscall
     number. Split in a 4-patches set to avoid kABI breakage when
     backporting to dead kernels"

* tag 'x86_urgent_for_v5.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/apic/of: Fix CPU devicetree-node lookups
  x86/ioapic: Ignore IRQ2 again
  x86: Introduce restart_block->arch_data to remove TS_COMPAT_RESTART
  x86: Introduce TS_COMPAT_RESTART to fix get_nr_restart_syscall()
  x86: Move TS_COMPAT back to asm/thread_info.h
  kernel, fs: Introduce and use set_restart_fn() and arch_set_restart_data()

Pull powerpc fixes from Michael Ellerman:

 - Fix a possible stack corruption and subsequent DLPAR failure in the
   rpadlpar_io PCI hotplug driver

 - Two build fixes for uncommon configurations

Thanks to Christophe Leroy and Tyrel Datwyler.

* tag 'powerpc-5.12-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  PCI: rpadlpar: Fix potential drc_name corruption in store functions
  powerpc: Force inlining of cpu_has_feature() to avoid build failure
  powerpc/vdso32: Add missing _restgpr_31_x to fix build failure

Without that it's not safe to use them in a linked combination with
others.

Now combinations like IORING_OP_SENDMSG followed by IORING_OP_SPLICE
should be possible.

We already handle short reads and writes for the following opcodes:

- IORING_OP_READV
- IORING_OP_READ_FIXED
- IORING_OP_READ
- IORING_OP_WRITEV
- IORING_OP_WRITE_FIXED
- IORING_OP_WRITE
- IORING_OP_SPLICE
- IORING_OP_TEE

Now we have it for these as well:

- IORING_OP_SENDMSG
- IORING_OP_SEND
- IORING_OP_RECVMSG
- IORING_OP_RECV

For IORING_OP_RECVMSG we also check for the MSG_TRUNC and MSG_CTRUNC
flags in order to call req_set_fail_links().

There might be applications arround depending on the behavior
that even short send[msg]()/recv[msg]() retuns continue an
IOSQE_IO_LINK chain.

It's very unlikely that such applications pass in MSG_WAITALL,
which is only defined in 'man 2 recvmsg', but not in 'man 2 sendmsg'.

It's expected that the low level sock_sendmsg() call just ignores
MSG_WAITALL, as MSG_ZEROCOPY is also ignored without explicitly set
SO_ZEROCOPY.

We also expect the caller to know about the implicit truncation to
MAX_RW_COUNT, which we don't detect.

cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/c4e1a4cc0d905314f4d5dc567e65a7b09621aab3.1615908477.git.metze@samba.orgSigned-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Mark the current task as running if we need to run task_work from the
io-wq threads as part of work handling. If that is the case, then return
as such so that the caller can appropriately loop back and reset if it
was part of a going-to-sleep flush.

Fixes: 3bfe6106 ("io-wq: fork worker threads from original task")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Just like we don't allow normal signals to IO threads, don't deliver a
STOP to a task that has PF_IO_WORKER set. The IO threads don't take
signals in general, and have no means of flushing out a stop either.

Longer term, we may want to look into allowing stop of these threads,
as it relates to eg process freezing. For now, this prevents a spin
issue if a SIGSTOP is delivered to the parent task.
Reported-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

They don't take signals individually, and even if they share signals with
the parent task, don't allow them to be delivered through the worker
thread. Linux does allow this kind of behavior for regular threads, but
it's really a compatability thing that we need not care about for the IO
threads.
Reported-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Signed-off-by: Theodore Ts'o <tytso@mit.edu>