Add an iterator, ITER_XARRAY, that walks through a set of pages attached to
an xarray, starting at a given page and offset and walking for the
specified amount of bytes.  The iterator supports transparent huge pages.

The iterate_xarray() macro calls the helper function with rcu_access()
helped.  I think that this is only a problem for iov_iter_for_each_range()
- and that returns an error for ITER_XARRAY (also, this function does not
appear to be called).

The caller must guarantee that the pages are all present and they must be
locked using PG_locked, PG_writeback or PG_fscache to prevent them from
going away or being migrated whilst they're being accessed.

This is useful for copying data from socket buffers to inodes in network
filesystems and for transferring data between those inodes and the cache
using direct I/O.

Whilst it is true that ITER_BVEC could be used instead, that would require
a bio_vec array to be allocated to refer to all the pages - which should be
redundant if inode->i_pages also points to all these pages.

Note that older versions of this patch implemented an ITER_MAPPING instead,
which was almost the same.

Changes:
v7:
 - Rename iter_xarray_copy_pages() to iter_xarray_populate_pages()[1].
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: Alexander Viro <viro@zeniv.linux.org.uk>
cc: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: Christoph Hellwig <hch@lst.de>
cc: linux-mm@kvack.org
cc: linux-cachefs@redhat.com
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/3577430.1579705075@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/158861205740.340223.16592990225607814022.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/159465785214.1376674.6062549291411362531.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/160588477334.3465195.3608963255682568730.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161118129703.1232039.17141248432017826976.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161026313.2537118.14676007075365418649.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340386671.1303470.10752208972482479840.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539527815.286939.14607323792547049341.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653786033.2770958.14154191921867463240.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789064740.6155.11932541175173658065.stgit@warthog.procyon.org.uk/ # v6
Link: https://lore.kernel.org/r/27c369a8f42bb8a617672b2dc0126a5c6df5a050.camel@kernel.org [1]

Pull clk fixes from Stephen Boyd:
 "Three fixes for the Qualcomm clk driver: two for regressions this
  merge window and one for a long-standing problem that only popped up
  now that eMMC is being used"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: qcom: gcc-sc7180: Use floor ops for the correct sdcc1 clk
  clk: qcom: rcg2: Rectify clk_gfx3d rate rounding without mux division
  clk: qcom: rpmh: Update the XO clock source for SC7280

Merge tag 'platform-drivers-x86-v5.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86

Pull x86 platform drivers fixes from Hans de Goede:
 "A set of bug-fixes and some model specific quirks.

  Summary:

   - dell-wmi-sysman: A set of probe-error-exit-handling fixes to fix
     some systems which advertise the WMI GUIDs, but are not compatible,
     not booting

   - intel-vbtn/intel-hid: Misc. bugfixes

   - intel_pmc: Bug-fixes + a quirk to lower suspend power-consumption
     on Tiger Lake

   - thinkpad_acpi: misc bugfixes"

* tag 'platform-drivers-x86-v5.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86:
  platform/x86: intel_pmc_core: Ignore GBE LTR on Tiger Lake platforms
  platform/x86: intel_pmc_core: Update Kconfig
  platform/x86: intel_pmt_crashlog: Fix incorrect macros
  platform/x86: intel_pmt_class: Initial resource to 0
  platform/x86: intel-vbtn: Stop reporting SW_DOCK events
  platform/x86: dell-wmi-sysman: Cleanup create_attributes_level_sysfs_files()
  platform/x86: dell-wmi-sysman: Make sysman_init() return -ENODEV of the interfaces are not found
  platform/x86: dell-wmi-sysman: Cleanup sysman_init() error-exit handling
  platform/x86: dell-wmi-sysman: Fix release_attributes_data() getting called twice on init_bios_attributes() failure
  platform/x86: dell-wmi-sysman: Make it safe to call exit_foo_attributes() multiple times
  platform/x86: dell-wmi-sysman: Fix possible NULL pointer deref on exit
  platform/x86: dell-wmi-sysman: Fix crash caused by calling kset_unregister twice
  platform/x86: thinkpad_acpi: Disable DYTC CQL mode around switching to balanced mode
  platform/x86: thinkpad_acpi: Allow the FnLock LED to change state
  platform/x86: thinkpad_acpi: check dytc version for lapmode sysfs
  platform/x86: intel-hid: Support Lenovo ThinkPad X1 Tablet Gen 2

Merge tag 'afs-cachefiles-fixes-20210323' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull cachefiles and afs fixes from David Howells:
 "Fixes from Matthew Wilcox for page waiting-related issues in
  cachefiles and afs as extracted from his folio series[1]:

   - In cachefiles, remove the use of the wait_bit_key struct to access
     something that's actually in wait_page_key format. The proper
     struct is now available in the header, so that should be used
     instead.

   - Add a proper wait function for waiting killably on the page
     writeback flag. This includes a recent bugfix[2] that's not in the
     afs code.

   - In afs, use the function added in (2) rather than using
     wait_on_page_bit_killable() which doesn't provide the
     aforementioned bugfix"

Link: https://lore.kernel.org/r/20210320054104.1300774-1-willy@infradead.org[1]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c2407cf7d22d0c0d94cf20342b3b8f06f1d904e7 [2]
Link: https://lore.kernel.org/r/20210323120829.GC1719932@casper.infradead.org/ # v1

* tag 'afs-cachefiles-fixes-20210323' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Use wait_on_page_writeback_killable
  mm/writeback: Add wait_on_page_writeback_killable
  fs/cachefiles: Remove wait_bit_key layout dependency

Based on discussions (e.g. in [1]) my understanding of cachefiles and
the cachefiles userspace daemon is that it creates a cache on a local
filesystem (e.g. ext4, xfs etc.) for a network filesystem. The way this
is done is by writing "bind" to /dev/cachefiles and pointing it to the
directory to use as the cache.

Currently this directory can technically also be an idmapped mount but
cachefiles aren't yet fully aware of such mounts and thus don't take the
idmapping into account when creating cache entries. This could leave
users confused as the ownership of the files wouldn't match to what they
expressed in the idmapping. Block cache files on idmapped mounts until
the fscache rework is done and we have ported it to support idmapped
mounts.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/lkml/20210303161528.n3jzg66ou2wa43qb@wittgenstein [1]
Link: https://lore.kernel.org/r/20210316112257.2974212-1-christian.brauner@ubuntu.com/ # v1
Link: https://listman.redhat.com/archives/linux-cachefs/2021-March/msg00044.html # v2
Link: https://lore.kernel.org/r/20210319114146.410329-1-christian.brauner@ubuntu.com/ # v3
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Open-coding this function meant it missed out on the recent bugfix
for waiters being woken by a delayed wake event from a previous
instantiation of the page[1].

[DH: Changed the patch to use vmf->page rather than variable page which
 doesn't exist yet upstream]

Fixes: 1cf7a151 ("afs: Implement shared-writeable mmap")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: kafs-testing@auristor.com
cc: linux-afs@lists.infradead.org
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/20210320054104.1300774-4-willy@infradead.org
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c2407cf7d22d0c0d94cf20342b3b8f06f1d904e7 [1]

This is the killable version of wait_on_page_writeback.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: kafs-testing@auristor.com
cc: linux-afs@lists.infradead.org
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/20210320054104.1300774-3-willy@infradead.org

Cachefiles was relying on wait_page_key and wait_bit_key being the
same layout, which is fragile.  Now that wait_page_key is exposed in
the pagemap.h header, we can remove that fragility

A comment on the need to maintain structure layout equivalence was added by
Linus[1] and that is no longer applicable.

Fixes: 62906027 ("mm: add PageWaiters indicating tasks are waiting for a page bit")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: kafs-testing@auristor.com
cc: linux-cachefs@redhat.com
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/20210320054104.1300774-2-willy@infradead.org/
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3510ca20ece0150af6b10c77a74ff1b5c198e3e2 [1]

Due to a HW limitation, the Latency Tolerance Reporting (LTR) value
programmed in the Tiger Lake GBE controller is not large enough to allow
the platform to enter Package C10, which in turn prevents the platform from
achieving its low power target during suspend-to-idle.  Ignore the GBE LTR
value on Tiger Lake. LTR ignore functionality is currently performed solely
by a debugfs write call. Split out the LTR code into its own function that
can be called by both the debugfs writer and by this work around.
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Reviewed-by: Sasha Neftin <sasha.neftin@intel.com>
Cc: intel-wired-lan@lists.osuosl.org
Reviewed-by: Rajneesh Bhardwaj <irenic.rajneesh@gmail.com>
Link: https://lore.kernel.org/r/20210319201844.3305399-2-david.e.box@linux.intel.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

The intel_pmc_core driver is mostly used as a debugging driver for Intel
platforms that support SLPS0 (S0ix). But the driver may also be used to
communicate actions to the PMC in order to ensure transition to SLPS0 on
some systems and architectures. As such the driver should be built on all
platforms it supports. Indicate this in the Kconfig. Also update the list
of supported features.
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Suggested-by: Mario Limonciello <mario.limonciello@dell.com>
Link: https://lore.kernel.org/r/20210319201844.3305399-1-david.e.box@linux.intel.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

Fixes off-by-one bugs in the macro assignments for the crashlog control
bits. Was initially tested on emulation but bug revealed after testing on
silicon.

Fixes: 5ef9998c ("platform/x86: Intel PMT Crashlog capability driver")
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Link: https://lore.kernel.org/r/20210317024455.3071477-2-david.e.box@linux.intel.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

Initialize the struct resource in intel_pmt_dev_register to zero to avoid a
fault should the char *name field be non-zero.
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Link: https://lore.kernel.org/r/20210317024455.3071477-1-david.e.box@linux.intel.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

Merge tag 'linux-kselftest-kunit-fixes-5.12-rc5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull KUnit fixes from Shuah Khan:
 "Two fixes to the kunit tool from David Gow"

* tag 'linux-kselftest-kunit-fixes-5.12-rc5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  kunit: tool: Disable PAGE_POISONING under --alltests
  kunit: tool: Fix a python tuple typing error

Pull selinux fixes from Paul Moore:
 "Three SELinux patches:

   - Fix a problem where a local variable is used outside its associated
     function. Thankfully this can only be triggered by reloading the
     SELinux policy, which is a restricted operation for other obvious
     reasons.

   - Fix some incorrect, and inconsistent, audit and printk messages
     when loading the SELinux policy.

  All three patches are relatively minor and have been through our
  testing with no failures"

* tag 'selinux-pr-20210322' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinuxfs: unify policy load error reporting
  selinux: fix variable scope issue in live sidtab conversion
  selinux: don't log MAC_POLICY_LOAD record on failed policy load

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

Stop reporting SW_DOCK events because this breaks suspend-on-lid-close.

SW_DOCK should only be reported for docking stations, but all the DSDTs in
my DSDT collection which use the intel-vbtn code, always seem to use this
for 2-in-1s / convertibles and set SW_DOCK=1 when in laptop-mode (in tandem
with setting SW_TABLET_MODE=0).

This causes userspace to think the laptop is docked to a port-replicator
and to disable suspend-on-lid-close, which is undesirable.

Map the dock events to KEY_IGNORE to avoid this broken SW_DOCK reporting.

Note this may theoretically cause us to stop reporting SW_DOCK on some
device where the 0xCA and 0xCB intel-vbtn events are actually used for
reporting docking to a classic docking-station / port-replicator but
I'm not aware of any such devices.

Also the most important thing is that we only report SW_DOCK when it
reliably reports being docked to a classic docking-station without any
false positives, which clearly is not the case here. If there is a
chance of reporting false positives then it is better to not report
SW_DOCK at all.

Cc: stable@vger.kernel.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210321163513.72328-1-hdegoede@redhat.com

Cleanup create_attributes_level_sysfs_files():

1. There is no need to call sysfs_remove_file() on error, sysman_init()
will already call release_attributes_data() on failure which already does
this.

2. There is no need for the pr_debug() calls sysfs_create_file() should
never fail and if it does it will already complain about the problem
itself.

Fixes: e8a60aa7 ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
Cc: Divya Bharathi <Divya_Bharathi@dell.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210321115901.35072-8-hdegoede@redhat.com

When either the attributes or the password interface is not found, then
unregister the 2 wmi drivers again and return -ENODEV from sysman_init().

Fixes: e8a60aa7 ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
Cc: Divya Bharathi <Divya_Bharathi@dell.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Reported-by: Alexander Naumann <alexandernaumann@gmx.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210321115901.35072-7-hdegoede@redhat.com

Cleanup sysman_init() error-exit handling:

1. There is no need for the fail_reset_bios and fail_authentication_kset
   eror-exit cases, these can be handled by release_attributes_data()

2. Rename all the labels from fail_what_failed, to err_what_to_cleanup
   this is the usual way to name these and avoids the need to rename
   them when extra steps are added.

Fixes: e8a60aa7 ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
Cc: Divya Bharathi <Divya_Bharathi@dell.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210321115901.35072-6-hdegoede@redhat.com

platform/x86: dell-wmi-sysman: Fix release_attributes_data() getting called twice on init_bios_attributes() failure

All calls of init_bios_attributes() will result in a
goto fail_create_group if they fail, which calls
release_attributes_data().

So there is no need to call release_attributes_data() from
init_bios_attributes() on failure itself.

Fixes: e8a60aa7 ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
Cc: Divya Bharathi <Divya_Bharathi@dell.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210321115901.35072-5-hdegoede@redhat.com

During some of the error-exit paths it is possible that
release_attributes_data() will get called multiple times,
which results in exit_foo_attributes() getting called multiple
times.

Make it safe to call exit_foo_attributes() multiple times,
avoiding double-free()s in this case.

Note that release_attributes_data() really should only be called
once during error-exit paths. This will be fixed in a separate patch
and it is good to have the exit_foo_attributes() functions modified
this way regardless.

Fixes: e8a60aa7 ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
Cc: Divya Bharathi <Divya_Bharathi@dell.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210321115901.35072-4-hdegoede@redhat.com

It is possible for release_attributes_data() to get called when the
main_dir_kset has not been created yet, move the removal of the bios-reset
sysfs attr to under a if (main_dir_kset) check to avoid a NULL pointer
deref.

Fixes: e8a60aa7 ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
Cc: Divya Bharathi <Divya_Bharathi@dell.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Reported-by: Alexander Naumann <alexandernaumann@gmx.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210321115901.35072-3-hdegoede@redhat.com

On some system the WMI GUIDs used by dell-wmi-sysman are present but there
are no enum type attributes, this causes init_bios_attributes() to return
-ENODEV, after which sysman_init() does a "goto fail_create_group" and then
calls release_attributes_data().

release_attributes_data() calls kset_unregister(wmi_priv.main_dir_kset);
but before this commit it was missing a "wmi_priv.main_dir_kset = NULL;"
statement; and after calling release_attributes_data() the sysman_init()
error handling does this:

        if (wmi_priv.main_dir_kset) {
                kset_unregister(wmi_priv.main_dir_kset);
                wmi_priv.main_dir_kset = NULL;
        }

Which causes a second kset_unregister(wmi_priv.main_dir_kset), leading to
a double-free, which causes a crash.

Add the missing "wmi_priv.main_dir_kset = NULL;" statement to
release_attributes_data() to fix this double-free crash.

Fixes: e8a60aa7 ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
Cc: Divya Bharathi <Divya_Bharathi@dell.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210321115901.35072-2-hdegoede@redhat.com

Testing has shown that setting /sys/firmware/acpi/platform_profile to
"balanced" when /sys/bus/platform/devices/thinkpad_acpi/dytc_lapmode
reports 1, causes dytc_lapmode to get reset to 0 and then it becomes
stuck at 0 for aprox. 30 minutes even if the laptop is used on a lap.

Disabling CQL (when enabled) before issuing the DYTC_CMD_RESET to get
back to balanced mode and re-enabling it afterwards again, like the
code already does when switching to low-power / performance mode fixes
this.

Fixes: c3bfcd4c ("platform/x86: thinkpad_acpi: Add platform profile support")
Tested-by: Mark Pearson <markpearson@lenovo.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210321113108.7069-1-hdegoede@redhat.com

On many recent ThinkPad laptops, there's a new LED next to the ESC key,
that indicates the FnLock status.
When the Fn+ESC combo is pressed, FnLock is toggled, which causes the
Media Key functionality to change, making it so that the media keys
either perform their media key function, or function as an F-key by
default. The Fn key can be used the access the alternate function at any
time.

With the current linux kernel, the LED doens't change state if you press
the Fn+ESC key combo. However, the media key functionality *does*
change. This is annoying, since the LED will stay on if it was on during
bootup, and it makes it hard to keep track what the current state of the
FnLock is.

This patch calls an ACPI function, that gets the current media key
state, when the Fn+ESC key combo is pressed. Through testing it was
discovered that this function causes the LED to update correctly to
reflect the current state when this function is called.

The relevant ACPI calls are the following:
\_SB_.PCI0.LPC0.EC0_.HKEY.GMKS: Get media key state, returns 0x603 if the FnLock mode is enabled, and 0x602 if it's disabled.
\_SB_.PCI0.LPC0.EC0_.HKEY.SMKS: Set media key state, sending a 1 will enable FnLock mode, and a 0 will disable it.

Relevant discussion:
https://bugzilla.kernel.org/show_bug.cgi?id=207841
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1881015Signed-off-by: Esteve Varela Colominas <esteve.varela@gmail.com>
Link: https://lore.kernel.org/r/20210315195823.23212-1-esteve.varela@gmail.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

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>