The driver core now has the ability to handle the creation and removal
of device-specific sysfs files, let's use it instead of registering and
unregistering attributes by hand.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220903051119.1332808-2-dmitry.torokhov@gmail.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

The driver core now has the ability to handle the creation and removal
of device-specific sysfs files, let's use it instead of registering and
unregistering attributes by hand.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220903051119.1332808-1-dmitry.torokhov@gmail.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Add RT5120 PMIC power key support.
Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
Link: https://lore.kernel.org/r/1660100142-32493-4-git-send-email-u0084500@gmail.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Clarify properties definition, drop unused pinctrl-2 state 'gpio'.
Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220712101619.326120-3-francesco.dolcini@toradex.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Any IIO ADC can be used with the driver, so do not depend
on VF610_ADC.
Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/r/20220712101619.326120-2-francesco.dolcini@toradex.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

With the new PM macros (DEFINE_SIMPLE_DEV_PM_OPS() and pm_sleep_ptr()), the
compiler has visibility to see that the functions are not used when
!CONFIG_PM and hence, remove the dead code. As such, there's no need
for '__maybe_unused'.
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220829131553.690063-11-nuno.sa@analog.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Support feeding VCC through a regulator.
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220829131553.690063-10-nuno.sa@analog.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Optionally reset the device during probe.
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220829131553.690063-9-nuno.sa@analog.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Just some code cleanup regarding coding style. With the introduction of
the bits.h macros changes in the code are indeed introduced.
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220829131553.690063-8-nuno.sa@analog.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

There's no need for an extra check for 'client-irq'. Just let it fail when
calling 'request_irq()'.
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220829131553.690063-7-nuno.sa@analog.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Add device tree bindings for the adp5588-keys driver.
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220829131553.690063-6-nuno.sa@analog.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Use firmware properties (eg: OF) to get the device specific
configuration. This change just replaces the platform data since there
was no platform using it and so, it makes no sense having both.

Special note to the PULL-UP disable setting that is now supported as
part of the gpio subsystem (using 'set_config()' callback).
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220829131553.690063-5-nuno.sa@analog.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Don't continue in code paths after some error is found. It makes no
sense to do any other device configuration if a previous one failed.
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220829131553.690063-4-nuno.sa@analog.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

With commit 9d2b2e83 ("Input: adp5588-keys - support gpi key events as
'gpio keys'") the irchip functionality is directly supported in the input
driver as the main goal of these pins is to be used as gpio keys. Hence,
this driver can be removed.
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Acked-by: Bartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220829131553.690063-3-nuno.sa@analog.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

This change replaces the support for GPIs as key event generators.
Instead of reporting the events directly, we add a gpio based irqchip
so that these events can be consumed by keys defined in the gpio-keys
driver (as it's goal is indeed for keys on GPIOs capable of generating
interrupts). With this, the gpio-adp5588 driver can also be dropped.

The basic idea is that all the pins that are not being used as part of
the keymap matrix can be possibly requested as GPIOs by gpio-keys
(it's also fine to use these pins as plain interrupts though that's not
really the point).

Since the gpiochip now also has irqchip capabilities, we should only
remove it after we free the device interrupt (otherwise we could, in
theory, be handling GPIs interrupts while the gpiochip is concurrently
removed). Thus the call 'adp5588_gpio_add()' is moved and since the
setup phase also needs to come before making the gpios visible, we also
need to move 'adp5588_setup()'.

While at it, always select GPIOLIB so that we don't need to use #ifdef
guards.
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220829131553.690063-2-nuno.sa@analog.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

As a preparation to unexport of_gpio_named_count(), convert the
driver to use gpiod_count() instead.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220830183552.50695-1-andriy.shevchenko@linux.intel.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

There is no such dependency in the driver, but it's implicitly
used to have OF property APIs available. Replace that by device
property API and get rid of OF_GPIO dependency.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220830182839.47965-1-andriy.shevchenko@linux.intel.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20220818210156.8143-1-wsa+renesas@sang-engineering.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20220818210022.6865-1-wsa+renesas@sang-engineering.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Add polled input device support to the adc-joystick driver. This is
useful for devices which do not have hardware capable triggers on
their SARADC. Code modified from adc-joystick.c changes made by Maya
Matuszczyk.
Signed-off-by: Maya Matuszczyk <maccraft123mc@gmail.com>
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Link: https://lore.kernel.org/r/20220816210440.14260-3-macroalpha82@gmail.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Add poll-interval support for the adc-joystick documentation. This is
an optional value and if not provided the adc-joystick works as it
does today (with buffers). If this value is provided, the adc-joystick
driver is polled at the specified interval. The existing attribute of
"poll-interval" was used instead of complying with property-units.yaml
after discussion of the issue on the mailing list.
Signed-off-by: Maya Matuszczyk <maccraft123mc@gmail.com>
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Artur Rojek <contact@artur-rojek.eu>
Link: https://lore.kernel.org/r/20220816210440.14260-2-macroalpha82@gmail.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Add a driver to get the button events from the panel and provide
them to userspace with the input subsystem. The panel is
connected with I2C and controls the bus, so the driver registers
as an I2C slave device.
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com> # I2C slave parts
Link: https://lore.kernel.org/r/20220809204147.238132-3-eajames@linux.ibm.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Document the bindings for the IBM Operation Panel, which provides
a simple interface to control a server. It has a display and three
buttons.
Also update MAINTAINERS for the new file.
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20220809204147.238132-2-eajames@linux.ibm.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Merge branch 'i2c/make_remove_callback_void-immutable' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux into next

Sync up with the latest I2C code base to get updated prototype of I2C
bus remove() method.

The value returned by an i2c driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.
Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marek Behún <kabel@kernel.org> # for leds-turris-omnia
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Machata <petrm@nvidia.com> # for mlxsw
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> # for surface3_power
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> # for bmc150-accel-i2c + kxcjk-1013
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> # for media/* + staging/media/*
Acked-by: Miguel Ojeda <ojeda@kernel.org> # for auxdisplay/ht16k33 + auxdisplay/lcd2s
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # for versaclock5
Reviewed-by: Ajay Gupta <ajayg@nvidia.com> # for ucsi_ccg
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Acked-by: Peter Rosin <peda@axentia.se> # for i2c-mux-*, max9860
Acked-by: Adrien Grassein <adrien.grassein@gmail.com> # for lontium-lt8912b
Reviewed-by: Jean Delvare <jdelvare@suse.de> # for hwmon, i2c-core and i2c/muxes
Acked-by: Corey Minyard <cminyard@mvista.com> # for IPMI
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com> # for drivers/power
Acked-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

All platforms that provide a teardown callback return 0. New users are
supposed to not make use of platform support, so there is no
functionality lost.

This patch is a preparation for making i2c remove callbacks return void.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Returning an error value in an i2c remove callback results in a generic
error message being emitted by the i2c core, but otherwise it doesn't
make a difference. The device goes away anyhow and the devm cleanups are
called.

So instead of triggering the generic i2c error message, emit a more
helpful message if a problem occurs and return 0 to suppress the generic
message.

This patch is a preparation for making i2c remove callbacks return void.
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

The mutex might still be in use until the devm cleanup callback
devm_led_classdev_flash_release() is called. This only happens some time
after lm3601x_remove() completed.

Fixes: e63a7448 ("leds: lm3601x: Convert class registration to device managed")
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Returning an error value from an i2c remove callback results in an error
message being emitted by the i2c core, but otherwise it doesn't make a
difference. The device goes away anyhow and the devm cleanups are
called.

As lm3697_remove() already emits an error message on failure and the
additional error message by the i2c core doesn't add any useful
information, don't pass the error value up the stack. Instead continue
to clean up and return 0.

This patch is a preparation for making i2c remove callbacks return void.
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

A remove callback that just returns 0 is equivalent to no callback at all
as can be seen in i2c_device_remove(). So simplify accordingly.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Radix tree header includes gfp.h for __GFP_BITS_SHIFT only. Now we
have gfp_types.h for this.

Fixes powerpc allmodconfig build:

   In file included from include/linux/nodemask.h:97,
                    from include/linux/mmzone.h:17,
                    from include/linux/gfp.h:7,
                    from include/linux/radix-tree.h:12,
                    from include/linux/idr.h:15,
                    from include/linux/kernfs.h:12,
                    from include/linux/sysfs.h:16,
                    from include/linux/kobject.h:20,
                    from include/linux/pci.h:35,
                    from arch/powerpc/kernel/prom_init.c:24:
   include/linux/random.h: In function 'add_latent_entropy':
>> include/linux/random.h:25:46: error: 'latent_entropy' undeclared (first use in this function); did you mean 'add_latent_entropy'?
      25 |         add_device_randomness((const void *)&latent_entropy, sizeof(latent_entropy));
         |                                              ^~~~~~~~~~~~~~
         |                                              add_latent_entropy
   include/linux/random.h:25:46: note: each undeclared identifier is reported only once for each function it appears in
Reported-by: kernel test robot <lkp@intel.com>
CC: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull vfs lseek fix from Al Viro:
 "Fix proc_reg_llseek() breakage. Always had been possible if somebody
  left NULL ->proc_lseek, became a practical issue now"

* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  take care to handle NULL ->proc_lseek()

Easily done now, just by clearing FMODE_LSEEK in ->f_mode
during proc_reg_open() for such entries.

Fixes: 868941b1 "fs: remove no_llseek"
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull more xen updates from Juergen Gross:

 - fix the handling of the "persistent grants" feature negotiation
   between Xen blkfront and Xen blkback drivers

 - a cleanup of xen.config and adding xen.config to Xen section in
   MAINTAINERS

 - support HVMOP_set_evtchn_upcall_vector, which is more compliant to
   "normal" interrupt handling than the global callback used up to now

 - further small cleanups

* tag 'for-linus-6.0-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  MAINTAINERS: add xen config fragments to XEN HYPERVISOR sections
  xen: remove XEN_SCRUB_PAGES in xen.config
  xen/pciback: Fix comment typo
  xen/xenbus: fix return type in xenbus_file_read()
  xen-blkfront: Apply 'feature_persistent' parameter when connect
  xen-blkback: Apply 'feature_persistent' parameter when connect
  xen-blkback: fix persistent grants negotiation
  x86/xen: Add support for HVMOP_set_evtchn_upcall_vector

Merge tag 'perf-tools-fixes-for-v6.0-2022-08-13' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux

Pull more perf tool updates from Arnaldo Carvalho de Melo:

 - 'perf c2c' now supports ARM64, adjust its output to cope with
   differences with what is in x86_64. Now go find false sharing on
   ARM64 (at least Neoverse) as well!

 - Refactor the JSON processing, making the output more compact and thus
   reducing the size of the resulting perf binary

 - Improvements for 'perf offcpu' profiling, including tracking child
   processes

 - Update Intel JSON metrics and events files for broadwellde,
   broadwellx, cascadelakex, haswellx, icelakex, ivytown, jaketown,
   knightslanding, sapphirerapids, skylakex and snowridgex

 - Add 'perf stat' JSON output and a 'perf test' entry for it

 - Ignore memfd and anonymous mmap events if jitdump present

 - Refactor 'perf test' shell tests allowing subdirs

 - Fix an error handling path in 'parse_perf_probe_command()'

 - Fixes for the guest Intel PT tracing patchkit in the 1st batch of
   this merge window

 - Print debuginfod queries if -v option is used, to explain delays in
   processing when debuginfo servers are enabled to fetch DSOs with
   richer symbol tables

 - Improve error message for 'perf record -p not_existing_pid'

 - Fix openssl and libbpf feature detection

 - Add PMU pai_crypto event description for IBM z16 on 'perf list'

 - Fix typos and duplicated words on comments in various places

* tag 'perf-tools-fixes-for-v6.0-2022-08-13' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (81 commits)
  perf test: Refactor shell tests allowing subdirs
  perf vendor events: Update events for snowridgex
  perf vendor events: Update events and metrics for skylakex
  perf vendor events: Update metrics for sapphirerapids
  perf vendor events: Update events for knightslanding
  perf vendor events: Update metrics for jaketown
  perf vendor events: Update metrics for ivytown
  perf vendor events: Update events and metrics for icelakex
  perf vendor events: Update events and metrics for haswellx
  perf vendor events: Update events and metrics for cascadelakex
  perf vendor events: Update events and metrics for broadwellx
  perf vendor events: Update metrics for broadwellde
  perf jevents: Fold strings optimization
  perf jevents: Compress the pmu_events_table
  perf metrics: Copy entire pmu_event in find metric
  perf pmu-events: Hide the pmu_events
  perf pmu-events: Don't assume pmu_event is an array
  perf pmu-events: Move test events/metrics to JSON
  perf test: Use full metric resolution
  perf pmu-events: Hide pmu_events_map
  ...

Pull powerpc fixes from Michael Ellerman:

 - Ensure we never emit lwarx with EH=1 on 32-bit, because some 32-bit
   CPUs trap on it rather than ignoring it as they should.

 - Fix ftrace when building with clang, which was broken by some
   refactoring.

 - A couple of other minor fixes.

Thanks to Christophe Leroy, Naveen N.  Rao, Nick Desaulniers, Ondrej
Mosnacek, Pali Rohár, Russell Currey, and Segher Boessenkool.

* tag 'powerpc-6.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/kexec: Fix build failure from uninitialised variable
  powerpc/ppc-opcode: Fix PPC_RAW_TW()
  powerpc64/ftrace: Fix ftrace for clang builds
  powerpc: Make eh value more explicit when using lwarx
  powerpc: Don't hide eh field of lwarx behind a macro
  powerpc: Fix eh field when calling lwarx on PPC32

Pull /proc/mounts fix from Al Viro:
 "Fix for /proc/mounts escaping - escape the '#' character too"

* tag 'pull-work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: escape hash as well

Pull more cifs updates from Steve French:

 - two fixes for stable, one for a lock length miscalculation, and
   another fixes a lease break timeout bug

 - improvement to handle leases, allows the close timeout to be
   configured more safely

 - five restructuring/cleanup patches

* tag '5.20-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: Do not access tcon->cfids->cfid directly from is_path_accessible
  cifs: Add constructor/destructors for tcon->cfid
  SMB3: fix lease break timeout when multiple deferred close handles for the same file.
  smb3: allow deferred close timeout to be configurable
  cifs: Do not use tcon->cfid directly, use the cfid we get from open_cached_dir
  cifs: Move cached-dir functions into a separate file
  cifs: Remove {cifs,nfs}_fscache_release_page()
  cifs: fix lock length calculation

Enable multipage folio support for the afs filesystem.

Support has already been implemented in netfslib, fscache and cachefiles
and in most of afs, but I've waited for Matthew Wilcox's latest folio
changes.

Note that it does require a change to afs_write_begin() to return the
correct subpage.  This is a "temporary" change as we're working on
getting rid of the need for ->write_begin() and ->write_end()
completely, at least as far as network filesystems are concerned - but
it doesn't prevent afs from making use of the capability.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: kafs-testing@auristor.com
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/lkml/2274528.1645833226@warthog.procyon.org.uk/Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>