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This reverts commit dc23806a7c47 ("driver core: enforce device_lock for
driver_match_device()") and commit 289b14592cef ("driver core: fix
inverted "locked" suffix of driver_match_device()").
While technically correct, there is a major downside to this approach:
When a device is already present in the system and a driver is
registered on the same bus, we iterate over all devices registered on
this bus to see if one of them matches. If we come across an already
bound one where the corresponding driver crashed while holding the
device lock (e.g. in probe()) we can't make any progress anymore.
However, drivers are typically the least tested code in the kernel and
hence it is a case that is likely to happen regularly. Besides hurting
developer ergonomics, it potentially decreases chances of shutting
things down cleanly and obtaining logs in production environments as
well [1].
This came up in the context of a firewire bug, which only in combination
with the reverted commit, caused the machine to hang [2]. Additionally,
it was observed in [3].
Thus, revert commit dc23806a7c47 ("driver core: enforce device_lock for
driver_match_device()") and add a brief note clarifying that an
implementer of struct bus_type must not expect match() to be called with
the device lock held.
Link: https://lore.kernel.org/driver-core/DGRGTIRHA62X.3RY09D9SOK77P@kernel.org/ [1]
Link: https://lore.kernel.org/all/67f655bb-4d81-4609-b008-68d200255dd2@davidgow.net/ [2]
Link: https://lore.kernel.org/lkml/CALbr=LZ4v7N=tO1vgOsyj9AS+XuNbn6kG-QcF+PacdMjSo0iyw@mail.gmail.com/ [3]
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Closes: https://lore.kernel.org/driver-core/CAHk-=wgJ_L1C=HjcYJotg_zrZEmiLFJaoic+PWthjuQrutrfJw@mail.gmail.com/
Reviewed-by: Gui-Dong Han <hanguidong02@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260302002545.19389-1-dakr@kernel.org
[ Add additional Link: reference. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl
Pull pin control updates from Linus Walleij:
"Core changes:
- Drop the unused devm_pinctrl_unregister() function
- Move pretended generic pin control functionality out of the core
and into the Amlogic AM4 driver. We have something better coming
(hopefully)
New hardware support:
- Spacemit K3 (RISC-V) pin control support
- Atmel AT91 PIO4 (ARM32) SAMA7D65 pin control support
- Exynos9610 (ARM64) pin control support
- Qualcomm Mahua TLMM (ARM64) pin control support
- Microchip Polarfire MSSIO (RISC-V) pin control support
- Ocelot LAN9645XF (multiplatform) pin control support
Improvements:
- Using a few more guards for locking
- Various nonurgent fixes and tweaks"
* tag 'pinctrl-v7.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (73 commits)
pinctrl: generic: move function to amlogic-am4 driver
pinctrl: intel: Align Copyright note with corporate guidelines
pinctrl: mediatek: remove unused drv_offset field
pinctrl: canaan: k230: Fix NULL pointer dereference when parsing devicetree
pinctrl: single: fix refcount leak in pcs_add_gpio_func()
pinctrl: meson: amlogic-a4: Fix device node reference leak in bank helpers
pinctrl: qcom: sm8250-lpass-lpi: Fix i2s2_data_groups definition
pinctrl: core: Remove duplicate error messages
pinctrl: core: Simplify devm_pinctrl_*()
pinctrl: core: Remove unused devm_pinctrl_unregister()
dt-bindings: pinctrl: spacemit: fix drive-strength check warning
pinctrl: fix kismet issues with GENERIC_PINCTRL
pinctrl: tangier: Join tng_pinctrl_probe() into its wrapper
pinctrl: tangier: Remove duplicate error messages
pinctrl: lynxpoint: Remove duplicate error messages
pinctrl: cherryview: Remove duplicate error messages
pinctrl: baytrail: Remove duplicate error messages
pinctrl: intel: Remove duplicate error messages
pinctrl: equilibrium: Fix device node reference leak in pinbank_init()
dt-bindings: pinctrl: pinctrl-microchip-sgpio: add LAN969x
...
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In the current implementation driver_match_device() expects the device
lock to be held, while driver_match_device_locked() acquires the device
lock.
By convention it should be the other way around, hence swap the name of
both functions.
Fixes: dc23806a7c47 ("driver core: enforce device_lock for driver_match_device()")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Gui-Dong Han <hanguidong02@gmail.com>
Link: https://patch.msgid.link/20260131014211.12841-1-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
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Driver core fixes deferred from 6.19-rc7
[1, 2] were originally intended for -rc7. Patch [1] uncovered potential
deadlocks that require a few driver fixes; [2] is one such fix.
[1] https://patch.msgid.link/20260113162843.12712-1-hanguidong02@gmail.com
[2] https://patch.msgid.link/20260121141215.29658-1-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
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devres_for_each_res() is only used by .../firmware_loader/main.c, which
already includes base.h.
The usage of devres_for_each_res() by code outside of driver-core is
questionable, hence move it to base.h.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260119162920.77189-1-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
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pinctrl_bind_pins() is only used by driver core (as it should). Move it
out of the public header into base.h.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Linus Walleij <linusw@kernel.org>
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Currently, driver_match_device() is called from three sites. One site
(__device_attach_driver) holds device_lock(dev), but the other two
(bind_store and __driver_attach) do not. This inconsistency means that
bus match() callbacks are not guaranteed to be called with the lock
held.
Fix this by introducing driver_match_device_locked(), which guarantees
holding the device lock using a scoped guard. Replace the unlocked calls
in bind_store() and __driver_attach() with this new helper. Also add a
lock assertion to driver_match_device() to enforce this guarantee.
This consistency also fixes a known race condition. The driver_override
implementation relies on the device_lock, so the missing lock led to the
use-after-free (UAF) reported in Bugzilla for buses using this field.
Stress testing the two newly locked paths for 24 hours with
CONFIG_PROVE_LOCKING and CONFIG_LOCKDEP enabled showed no UAF recurrence
and no lockdep warnings.
Cc: stable@vger.kernel.org
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789
Suggested-by: Qiu-ji Chen <chenqiuji666@gmail.com>
Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com>
Fixes: 49b420a13ff9 ("driver core: check bus->match without holding device lock")
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Link: https://patch.msgid.link/20260113162843.12712-1-hanguidong02@gmail.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
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In C dev_get_drvdata() has specific requirements under which it is valid
to access the returned pointer. That is, drivers have to ensure that
(1) for the duration the returned pointer is accessed the driver is
bound and remains to be bound to the corresponding device,
(2) the returned void * is treated according to the driver's private
data type, i.e. according to what has been passed to
dev_set_drvdata().
In Rust, (1) can be ensured by simply requiring the Bound device
context, i.e. provide the drvdata() method for Device<Bound> only.
For (2) we would usually make the device type generic over the driver
type, e.g. Device<T: Driver>, where <T as Driver>::Data is the type of
the driver's private data.
However, a device does not have a driver type known at compile time and
may be bound to multiple drivers throughout its lifetime.
Hence, in order to be able to provide a safe accessor for the driver's
device private data, we have to do the type check on runtime.
This is achieved by letting a driver assert the expected type, which is
then compared to a type hash stored in struct device_private when
dev_set_drvdata() is called.
Example:
// `dev` is a `&Device<Bound>`.
let data = dev.drvdata::<SampleDriver>()?;
There are two aspects to note:
(1) Technically, the same check could be achieved by comparing the
struct device_driver pointer of struct device with the struct
device_driver pointer of the driver struct (e.g. struct
pci_driver).
However, this would - in addition the pointer comparison - require
to tie back the private driver data type to the struct
device_driver pointer of the driver struct to prove correctness.
Besides that, accessing the driver struct (stored in the module
structure) isn't trivial and would result into horrible code and
API ergonomics.
(2) Having a direct accessor to the driver's private data is not
commonly required (at least in Rust): Bus callback methods already
provide access to the driver's device private data through a &self
argument, while other driver entry points such as IRQs,
workqueues, timers, IOCTLs, etc. have their own private data with
separate ownership and lifetime.
In other words, a driver's device private data is only relevant
for driver model contexts (such a file private is only relevant
for file contexts).
Having that said, the motivation for accessing the driver's device
private data with Device<Bound>::drvdata() are interactions between
drivers. For instance, when an auxiliary driver calls back into its
parent, the parent has to be capable to derive its private data from the
corresponding device (i.e. the parent of the auxiliary device).
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ * Remove unnecessary `const _: ()` block,
* rename type_id_{store,match}() to {set,match}_type_id(),
* assert size_of::<bindings::driver_type>() >= size_of::<TypeId>(),
* add missing check in case Device::drvdata() is called from probe().
- Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
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Device links with DL_FLAG_SYNC_STATE_ONLY should not affect system
suspend and resume, and functions like device_reorder_to_tail() and
device_link_add() don't try to reorder the consumers with that flag.
However, dpm_wait_for_consumers() and dpm_wait_for_suppliers() don't
check thas flag before triggering dpm_wait(), leading to potential hang
during suspend/resume.
This can be reproduced on MT8186 Corsola Chromebook with devicetree like:
usb-a-connector {
compatible = "usb-a-connector";
port {
usb_a_con: endpoint {
remote-endpoint = <&usb_hs>;
};
};
};
usb_host {
compatible = "mediatek,mt8186-xhci", "mediatek,mtk-xhci";
port {
usb_hs: endpoint {
remote-endpoint = <&usb_a_con>;
};
};
};
In this case, the two nodes form a cycle and a SYNC_STATE_ONLY devlink
between usb_host (supplier) and usb-a-connector (consumer) is created.
Address this by exporting device_link_flag_is_sync_state_only() and
making dpm_wait_for_consumers() and dpm_wait_for_suppliers() use it
when deciding if dpm_wait() should be called.
Fixes: 05ef983e0d65a ("driver core: Add device link support for SYNC_STATE_ONLY flag")
Signed-off-by: Pin-yen Lin <treapking@chromium.org>
Link: https://patch.msgid.link/20250926102320.4053167-1-treapking@chromium.org
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Add separate macros for walking links to suppliers and consumers of a
device to help device links users to avoid exposing the internals of
struct dev_links_info in their code and possible coding mistakes related
to that.
Accordingly, use the new macros to replace open-coded device links list
walks in the core power management code.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/1944671.tdWV9SEqCh@rafael.j.wysocki
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If userspace reads "uevent" device attribute at the same time as another
threads unbinds the device from its driver, change to dev->driver from a
valid pointer to NULL may result in crash. Fix this by using READ_ONCE()
when fetching the pointer, and take bus' drivers klist lock to make sure
driver instance will not disappear while we access it.
Use WRITE_ONCE() when setting the driver pointer to ensure there is no
tearing.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20250311052417.1846985-3-dmitry.torokhov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In preparation to closing a race when reading driver pointer in
dev_uevent() code, instead of setting device->driver pointer directly
introduce device_set_driver() helper.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20250311052417.1846985-2-dmitry.torokhov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Many drivers abuse the platform driver/bus system as it provides a
simple way to create and bind a device to a driver-specific set of
probe/release functions. Instead of doing that, and wasting all of the
memory associated with a platform device, here is a "faux" bus that
can be used instead.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Zijun Hu <quic_zijuhu@quicinc.com>
Link: https://lore.kernel.org/r/2025021026-atlantic-gibberish-3f0c@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This reverts commit 8064952c65045f05ee2671fe437770e50c151776.
The series is being reverted before -rc1 as there are still reports of
lockups on shutdown, so it's not quite ready for "prime time."
Reported-by: Andrey Skvortsov <andrej.skvortzov@gmail.com>
Link: https://lore.kernel.org/r/ZvMkkhyJrohaajuk@skv.local
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Jeffery <djeffery@redhat.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Stuart Hayes <stuart.w.hayes@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add code to allow asynchronous shutdown of devices, ensuring that each
device is shut down before its parents & suppliers.
Only devices with drivers that have async_shutdown_enable enabled will be
shut down asynchronously.
This can dramatically reduce system shutdown/reboot time on systems that
have multiple devices that take many seconds to shut down (like certain
NVMe drives). On one system tested, the shutdown time went from 11 minutes
without this patch to 55 seconds with the patch.
Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com>
Signed-off-by: David Jeffery <djeffery@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Tested-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20240822202805.6379-4-stuart.w.hayes@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Function struct kobject *virtual_device_parent(struct device *dev)
does not use its parameter @dev, and the kobject returned also has
nothing deal with specific device, so remove the unused parameter.
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Link: https://lore.kernel.org/r/20240725-virtual_kobj_fix-v1-1-36335cae4544@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The functions module_add_driver() and module_remove_driver() do not
modify the struct device_driver structure directly, so they are safe to
be marked as a constant pointer type.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/2024070850-entering-grandson-205e@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In the match() callback, the struct device_driver * should not be
changed, so change the function callback to be a const *. This is one
step of many towards making the driver core safe to have struct
device_driver in read-only memory.
Because the match() callback is in all busses, all busses are modified
to handle this properly. This does entail switching some container_of()
calls to container_of_const() to properly handle the constant *.
For some busses, like PCI and USB and HV, the const * is cast away in
the match callback as those busses do want to modify those structures at
this point in time (they have a local lock in the driver structure.)
That will have to be changed in the future if they wish to have their
struct device * in read-only-memory.
Cc: Rafael J. Wysocki <rafael@kernel.org>
Reviewed-by: Alex Elder <elder@kernel.org>
Acked-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Change device_driver_attach() and driver_attach() to take a const * to
struct device driver as neither of them modify the structure at all.
Also, for some odd reason, drivers/dma/idxd/compat.c had a duplicate
external reference to device_driver_attach(), so remove that to fix up
the build, it should never have had that there in the first place.
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Petr Tesarik <petr.tesarik.ext@huawei.com>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: dmaengine@vger.kernel.org
Link: https://lore.kernel.org/r/2024061401-rasping-manger-c385@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Within struct device_private, mark the async_driver * as const as it is
never modified. This requires some internal-to-the-driver-core
functions to also have their parameters marked as constant, and there is
one place where we cast _back_ from the const pointer to a real one, as
the driver core still wants to modify the structure in a number of
remaining places.
Cc: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20240611130103.3262749-12-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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driver_detach() does not modify the driver itself, so make the pointer
constant. In doing so, the function driver_allows_async_probing() also
needs to be changed so that the pointer type passes through to that
function properly.
Cc: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20240611130103.3262749-11-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Change device_release_driver_internal() to take a const struct
device_driver * as it is not modifying it at all.
Cc: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20240611130103.3262749-10-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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driver_add_groups() and driver_remove_groups should take a constant
pointer as the structure is not modified, so make the change.
Cc: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20240611130103.3262749-9-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The sysfs_create_link() return code is marked as __must_check, but the
module_add_driver() function tries hard to not care, by assigning the
return code to a variable. When building with 'make W=1', gcc still
warns because this variable is only assigned but not used:
drivers/base/module.c: In function 'module_add_driver':
drivers/base/module.c:36:6: warning: variable 'no_warn' set but not used [-Wunused-but-set-variable]
Rework the code to properly unwind and return the error code to the
caller. My reading of the original code was that it tries to
not fail when the links already exist, so keep ignoring -EEXIST
errors.
Fixes: e17e0f51aeea ("Driver core: show drivers in /sys/module/")
See-also: 4a7fb6363f2d ("add __must_check to device management code")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20240408080616.3911573-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the block_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240305-class_cleanup-block-v1-1-130bb27b9c72@marliere.net
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Now that the class code is cleaned up to not modify the class pointer
registered with it, change class_register() to take a const * to allow
the structure to be placed into read-only memory.
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/2023040248-customary-release-4aec@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Nothing outside of drivers/base/core.c uses sysfs_dev_char_kobj, so
make it static and document what it is used for so we remember it the
next time we touch it 15 years from now.
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230331093318.82288-7-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When a dev_t is set in a struct device, an symlink in /sys/dev/ is
created for it either under /sys/dev/block/ or /sys/dev/char/ depending
on the device type.
The logic to determine this would trigger off of the class of the
object, and the kobj_type set in that location. But it turns out that
this deep nesting isn't needed at all, as it's either a choice of block
or "everything else" which is a char device. So make the logic a lot
more simple and obvious, and remove the incorrect comments in the code
that tried to document something that was not happening at all (it is
impossible to set class->dev_kobj to NULL as the class core prevented
that from happening.
This removes the only place that class->dev_kobj was being used, so
after this, it can be removed entirely.
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230331093318.82288-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There are a number of places in core.c that need access to the private
subsystem structure of struct class, so move them to use
class_to_subsys() instead of accessing it directly.
This requires exporting class_to_subsys() out of class.c, but keeping it
local to the driver core.
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230331093318.82288-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The structure sysfs_dev_char_kobj is local only to the driver core code,
so move it out of the global class.h file and into the internal base.h
file as no one else should be touching this symbol.
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230327160319.513974-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In commit 37e98d9bedb5 ("driver core: bus: move lock_class_key into
dynamic structure"), the lock_key variable moved out of struct bus_type
and into struct subsys_private, yet the documentation for it did not
move. Fix that up and place the documentation comment in the correct
location.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Fixes: 37e98d9bedb5 ("driver core: bus: move lock_class_key into dynamic structure")
Link: https://lore.kernel.org/r/20230324090814.386654-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The kernel coding style does not require 'extern' in function prototypes
in .h files, so remove them from drivers/base/base.h as they are not
needed.
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230324122711.2664537-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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bus_register() is now safe to take a constant * to bus_type, so make
that change and mark the subsys_private bus_type * constant as well.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230313182918.1312597-24-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Now that all accesses of dev_root is through the bus_get_dev_root()
call, move the pointer out of struct bus_type and into the private
dynamic structure, subsys_private.
With this change, there is no modifiable portions of struct bus_type so
it can be marked as a constant structure and moved to read-only memory.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230313182918.1312597-22-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If the file is written to and sync_state() hasn't been called for the
device yet, then call sync_state() for the device independent of the
state of its consumers.
This is useful for supplier devices that have one or more consumers that
don't have a driver but the consumers are in a state that don't use the
resources supplied by the supplier device.
This gives finer grained control than using the
fw_devlink.sync_state=timeout kernel commandline parameter.
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20230304005355.746421-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When all devices that could probe have finished probing (based on
deferred_probe_timeout configuration or late_initcall() when
!CONFIG_MODULES), this parameter controls what to do with devices that
haven't yet received their sync_state() calls.
fw_devlink.sync_state=strict is the default and the driver core will
continue waiting on all consumers of a device to probe successfully
before sync_state() is called for the device. This is the default
behavior since calling sync_state() on a device when all its consumers
haven't probed could make some systems unusable/unstable. When this
option is selected, we also print the list of devices that haven't had
sync_state() called on them by the time all devices the could probe have
finished probing.
fw_devlink.sync_state=timeout will cause the driver core to give up
waiting on consumers and call sync_state() on any devices that haven't
yet received their sync_state() calls. This option is provided for
systems that won't become unusable/unstable as they might be able to
save power (depends on state of hardware before kernel starts) if all
devices get their sync_state().
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20230304005355.746421-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This reverts commit 9d3fe6aa6b9517408064c7c3134187e8ec77dbf7 as it is
reported to cause boot regressions.
Link: https://lore.kernel.org/r/Y+rSXg14z1Myd8Px@dev-arch.thelio-3990X
Reported-by: Nathan Chancellor <nathan@kernel.org>
Cc: Longlong Xia <xialonglong1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The only caller of device_del() does not check the return value. And
there's nothing we can do when cleaning things up on a remove path.
Let's make it a void function.
Signed-off-by: Longlong Xia <xialonglong1@huawei.com>
Link: https://lore.kernel.org/r/20230210095444.4067307-4-xialonglong1@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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A local function to the driver core to determine if a bus really is
registered with the kernel or not. To be used only by the driver core
code, as part of the driver registration path as it's not really "safe"
because the bus could be unregistered instantly after being called.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230208111330.439504-17-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We need to control the reference count of the subsys private structure
instead of directly manipulating the kset reference count of it, so wrap
that logic up in a subsys_get() and subsys_put() function to make it more
obvious as to what is happening.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230208111330.439504-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Move the lock_class_key structure out of struct bus_type and into the
dynamic structure we create already for all bus_types registered with
the kernel. This saves on static space and removes one more writable
field in struct bus_type.
In the future, the same field can be moved out of the struct class logic
because it shares this same private structure.
Most everyone will never notice this change, as lockdep is not enabled
in real systems so no memory or logic changes are happening for them.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20230201083349.4038660-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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device_get_devnode() should take a constant * to struct device as it
does not modify it in any way, so modify the function definition to do
this and move it out of device.h as it does not need to be exposed to
the whole kernel tree.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Won Chung <wonchung@google.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230111113018.459199-8-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The logic to touch the bus notifier was open-coded in numberous places
in the driver core. Clean that up by creating a local bus_notify()
function and have everyone call this function instead, making the
reading of the caller code simpler and easier to maintain over time.
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230111092331.3946745-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The macro to_subsys_private() needs to switch to using
container_of_const() as it turned out to being incorrectly casting a
const pointer to a non-const one. Make this change and fix up the one
offending user to be correctly handling a const pointer properly.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20230111093327.3955063-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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driver_allows_async_probing is only used in drivers/base/dd.c, so mark
it static and remove the declaration in drivers/base/base.h.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221030092255.872280-1-hch@lst.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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make_class_name has been removed since
commit 39aba963d937 ("driver core: remove CONFIG_SYSFS_DEPRECATED_V2
but keep it for block devices"), so remove it.
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Link: https://lore.kernel.org/r/20220909063337.1146151-1-cuigaosheng1@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Some devices might need to be probed and bound successfully before the
kernel boot sequence can finish and move on to init/userspace. For
example, a network interface might need to be bound to be able to mount
a NFS rootfs.
With fw_devlink=on by default, some of these devices might be blocked
from probing because they are waiting on a optional supplier that
doesn't have a driver. While fw_devlink will eventually identify such
devices and unblock the probing automatically, it might be too late by
the time it unblocks the probing of devices. For example, the IP4
autoconfig might timeout before fw_devlink unblocks probing of the
network interface.
This function is available to temporarily try and probe all devices that
have a driver even if some of their suppliers haven't been added or
don't have drivers.
The drivers can then decide which of the suppliers are optional vs
mandatory and probe the device if possible. By the time this function
returns, all such "best effort" probes are guaranteed to be completed.
If a device successfully probes in this mode, we delete all fw_devlink
discovered dependencies of that device where the supplier hasn't yet
probed successfully because they have to be optional dependencies.
This also means that some devices that aren't needed for init and could
have waited for their optional supplier to probe (when the supplier's
module is loaded later on) would end up probing prematurely with limited
functionality. So call this function only when boot would fail without
it.
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20220601070707.3946847-5-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The deferred probe timer that's used for this currently starts at
late_initcall and runs for driver_deferred_probe_timeout seconds. The
assumption being that all available drivers would be loaded and
registered before the timer expires. This means, the
driver_deferred_probe_timeout has to be pretty large for it to cover the
worst case. But if we set the default value for it to cover the worst
case, it would significantly slow down the average case. For this
reason, the default value is set to 0.
Also, with CONFIG_MODULES=y and the current default values of
driver_deferred_probe_timeout=0 and fw_devlink=on, devices with missing
drivers will cause their consumer devices to always defer their probes.
This is because device links created by fw_devlink defer the probe even
before the consumer driver's probe() is called.
Instead of a fixed timeout, if we extend an unexpired deferred probe
timer on every successful driver registration, with the expectation more
modules would be loaded in the near future, then the default value of
driver_deferred_probe_timeout only needs to be as long as the worst case
time difference between two consecutive module loads.
So let's implement that and set the default value to 10 seconds when
CONFIG_MODULES=y.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Rob Herring <robh@kernel.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Will Deacon <will@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kevin Hilman <khilman@kernel.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Cc: linux-gpio@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: iommu@lists.linux-foundation.org
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20220429220933.1350374-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Split software_node_notify_remove) out of software_node_notify()
and make device_platform_notify() call the latter on device addition
and the former on device removal.
While at it, put the headers of the above functions into base.h,
because they don't need to be present in a global header file.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
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This is intended as a replacement API for device_bind_driver(). It has at
least the following benefits:
- Internal locking. Few of the users of device_bind_driver() follow the
locking rules
- Calls device driver probe() internally. Notably this means that devm
support for probe works correctly as probe() error will call
devres_release_all()
- struct device_driver -> dev_groups is supported
- Simplified calling convention, no need to manually call probe().
The general usage is for situations that already know what driver to bind
and need to ensure the bind is synchronized with other logic. Call
device_driver_attach() after device_add().
If probe() returns a failure then this will be preserved up through to the
error return of device_driver_attach().
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20210617142218.1877096-6-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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