driver core: Introduce device_iter_t for device iterating APIs

There are several for_each APIs which has parameter with type below:
int (*fn)(struct device *dev, void *data)
They iterate over variou

driver core: Introduce device_iter_t for device iterating APIs

There are several for_each APIs which has parameter with type below:
int (*fn)(struct device *dev, void *data)
They iterate over various device lists and call @fn() for each device
with caller provided data @*data, and they usually need to modify @*data.

Give the type an dedicated typedef with advantages shown below:
typedef int (*device_iter_t)(struct device *dev, void *data)

- Shorter API declarations and definitions
- Prevent further for_each APIs from using bad parameter type

So introduce device_iter_t and apply it to various existing APIs below:
bus_for_each_dev()
(class|driver)_for_each_device()
device_for_each_child(_reverse|_reverse_from)().

Reviewed-by: Jonathan Cameron <[email protected]>
Signed-off-by: Zijun Hu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: Introduce an device matching API device_match_type()

Introduce device_match_type() for purposes below:

- Test if a device matches with a specified device type.
- As argument of various

driver core: Introduce an device matching API device_match_type()

Introduce device_match_type() for purposes below:

- Test if a device matches with a specified device type.
- As argument of various device finding APIs to find a device with
specified type.

device_find_child() will use it to simplify operations later.

Reviewed-by: Jonathan Cameron <[email protected]>
Signed-off-by: Zijun Hu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: add irq_get_affinity callback to bus_type

Introducing a callback in struct bus_type so that a subsystem
can hook up the getters directly. This approach avoids exposing
random gette

driver core: bus: add irq_get_affinity callback to bus_type

Introducing a callback in struct bus_type so that a subsystem
can hook up the getters directly. This approach avoids exposing
random getters in any subsystems APIs.

Acked-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Reviewed-by: Ming Lei <[email protected]>
Acked-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Daniel Wagner <[email protected]>
Link: https://lore.kernel.org/r/20241202-refactor-blk-affinity-helpers-v6-1-27211e9c2cd5@kernel.org
Signed-off-by: Jens Axboe <[email protected]>

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drivers/base: Introduce device_match_t for device finding APIs

There are several drivers/base APIs for finding a specific device, and
they currently use the following good type for the @match parame

drivers/base: Introduce device_match_t for device finding APIs

There are several drivers/base APIs for finding a specific device, and
they currently use the following good type for the @match parameter:
int (*match)(struct device *dev, const void *data)

Since these operations do not modify the caller-provided @*data, this
type is worthy of a dedicated typedef:
typedef int (*device_match_t)(struct device *dev, const void *data)

Advantages of using device_match_t:
- Shorter API declarations and definitions
- Prevent further APIs from using a bad type for @match

So introduce device_match_t and apply it to the existing
(bus|class|driver|auxiliary)_find_device() APIs.

Signed-off-by: Zijun Hu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: have match() callback in struct bus_type take a const *

In the match() callback, the struct device_driver * should not be
changed, so change the function callback to be a const *. This

driver core: have match() callback in struct bus_type take a const *

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 <[email protected]>
Reviewed-by: Alex Elder <[email protected]>
Acked-by: Sumit Garg <[email protected]>
Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: make bus_sort_breadthfirst() take a const pointer

For some reason, during the big "clean up the driver core for a const
struct bus_type" work, the bus_sort_breadthfirst() call was

driver core: bus: make bus_sort_breadthfirst() take a const pointer

For some reason, during the big "clean up the driver core for a const
struct bus_type" work, the bus_sort_breadthfirst() call was missed. Fix
this up by changing the type to be a const * as it should be.

Cc: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/2023121935-stinking-ditzy-fd5d@gregkh
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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iommu: Retire bus ops

With the rest of the API internals converted, it's time to finally
tackle probe_device and how we bootstrap the per-device ops association
to begin with. This ends up being dis

iommu: Retire bus ops

With the rest of the API internals converted, it's time to finally
tackle probe_device and how we bootstrap the per-device ops association
to begin with. This ends up being disappointingly straightforward, since
fwspec users are already doing it in order to find their of_xlate
callback, and it works out that we can easily do the equivalent for
other drivers too. Then shuffle the remaining awareness of iommu_ops
into the couple of core headers that still need it, and breathe a sigh
of relief.

Ding dong the bus ops are gone!

CC: Rafael J. Wysocki <[email protected]>
Acked-by: Christoph Hellwig <[email protected]>
Acked-by: Greg Kroah-Hartman <[email protected]>
Reviewed-by: Lu Baolu <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Jerry Snitselaar <[email protected]>
Signed-off-by: Robin Murphy <[email protected]>
Link: https://lore.kernel.org/r/a59011ef65b4b6657cb0b7a388d786b779b61305.1700589539.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <[email protected]>

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driver core: bus: move documentation for lock_key to proper location.

In commit 37e98d9bedb5 ("driver core: bus: move lock_class_key into
dynamic structure"), the lock_key variable moved out of stru

driver core: bus: move documentation for lock_key to proper location.

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" <[email protected]>
Fixes: 37e98d9bedb5 ("driver core: bus: move lock_class_key into dynamic structure")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus.h: remove extern from function prototypes

The kernel coding style does not require 'extern' in function prototypes
in .h files, so remove them from include/linux/device/bus.h as the

driver core: bus.h: remove extern from function prototypes

The kernel coding style does not require 'extern' in function prototypes
in .h files, so remove them from include/linux/device/bus.h as they are
not needed.

Acked-by: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: constify bus_rescan_devices()

The bus_rescan_devices() function was missed in the previous change of
the bus_for_each* constant pointer changes, so fix it up now to take a
const *

driver core: bus: constify bus_rescan_devices()

The bus_rescan_devices() function was missed in the previous change of
the bus_for_each* constant pointer changes, so fix it up now to take a
const * to struct bus_type.

Cc: "Rafael J. Wysocki" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: constantify bus_register()

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.

driver core: bus: constantify bus_register()

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" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: mark the struct bus_type for sysfs callbacks as constant

struct bus_type should never be modified in a sysfs callback as there is
nothing in the structure to modify, and frankly, t

driver core: bus: mark the struct bus_type for sysfs callbacks as constant

struct bus_type should never be modified in a sysfs callback as there is
nothing in the structure to modify, and frankly, the structure is almost
never used in a sysfs callback, so mark it as constant to allow struct
bus_type to be moved to read-only memory.

Cc: "David S. Miller" <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: "K. Y. Srinivasan" <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexandre Bounine <[email protected]>
Cc: Alison Schofield <[email protected]>
Cc: Ben Widawsky <[email protected]>
Cc: Dexuan Cui <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Haiyang Zhang <[email protected]>
Cc: Hannes Reinecke <[email protected]>
Cc: Harald Freudenberger <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Hu Haowen <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Laurentiu Tudor <[email protected]>
Cc: Matt Porter <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: Stuart Yoder <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vishal Verma <[email protected]>
Cc: Yanteng Si <[email protected]>
Acked-by: Ilya Dryomov <[email protected]> # rbd
Acked-by: Ira Weiny <[email protected]> # cxl
Reviewed-by: Alex Shi <[email protected]>
Acked-by: Iwona Winiarska <[email protected]>
Acked-by: Dan Williams <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]> # pci
Acked-by: Wei Liu <[email protected]>
Acked-by: Martin K. Petersen <[email protected]> # scsi
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: move dev_root out of struct bus_type

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

driver core: bus: move dev_root out of struct bus_type

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" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: add bus_get_dev_root() function

Instead of poking around in the struct bus_type directly for the
dev_root pointer, provide a function to return it properly reference
counted, if it

driver core: bus: add bus_get_dev_root() function

Instead of poking around in the struct bus_type directly for the
dev_root pointer, provide a function to return it properly reference
counted, if it is present in the bus. This will be needed to move the
pointer out of struct bus_type in the future.

Use the function in the driver core code at the same time it is
introduced to verify that it works properly.

Cc: "Rafael J. Wysocki" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: constify bus_unregister()

The bus_unregister() function can now take a const * to bus_type, not
just a * so fix that up.

Cc: "Rafael J. Wysocki" <[email protected]>
Link: https://

driver core: bus: constify bus_unregister()

The bus_unregister() function can now take a const * to bus_type, not
just a * so fix that up.

Cc: "Rafael J. Wysocki" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: constify bus_get_kset()

The bus_get_kset() function should be taking a const * to bus_type, not
just a * so fix that up.

Cc: "Rafael J. Wysocki" <[email protected]>
Link: https://

driver core: bus: constify bus_get_kset()

The bus_get_kset() function should be taking a const * to bus_type, not
just a * so fix that up.

Cc: "Rafael J. Wysocki" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: constify bus_register/unregister_notifier()

The bus_register_notifier() and bus_unregister_notifier() functions
should be taking a const * to bus_type, not just a * so fix that up.

driver core: bus: constify bus_register/unregister_notifier()

The bus_register_notifier() and bus_unregister_notifier() functions
should be taking a const * to bus_type, not just a * so fix that up.

Cc: "Rafael J. Wysocki" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: remove private pointer from struct bus_type

Now that the driver code has been refactored to not rely on the pointer
from a struct bus_type to the private structure it can be safely remo

driver core: remove private pointer from struct bus_type

Now that the driver code has been refactored to not rely on the pointer
from a struct bus_type to the private structure it can be safely removed
from the structure entirely.

This will allow most bus_type structures to now be marked as const.

Cc: "Rafael J. Wysocki" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: convert bus_create/remove_file to be constant

bus_create_file() and bus_remove_file() can be made to take a constant
bus pointer, as it should not be modifying anything in the bus

driver core: bus: convert bus_create/remove_file to be constant

bus_create_file() and bus_remove_file() can be made to take a constant
bus pointer, as it should not be modifying anything in the bus
structure. Make this change and move the functions to use the internal
subsys_get/put() logic as well, to prevent the use of the back-pointer
in struct bus_type.

Cc: "Rafael J. Wysocki" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: constantify the bus_find_* functions

All of the bus find and iterator functions do not modify the struct
bus_type passed to them, so mark them as constant to enforce this rule.

Cc

driver core: bus: constantify the bus_find_* functions

All of the bus find and iterator functions do not modify the struct
bus_type passed to them, so mark them as constant to enforce this rule.

Cc: "Rafael J. Wysocki" <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus: move lock_class_key into dynamic structure

Move the lock_class_key structure out of struct bus_type and into the
dynamic structure we create already for all bus_types registered wi

driver core: bus: move lock_class_key into dynamic structure

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" <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: make struct bus_type.uevent() take a const *

The uevent() callback in struct bus_type should not be modifying the
device that is passed into it, so mark it as a const * and propagate th

driver core: make struct bus_type.uevent() take a const *

The uevent() callback in struct bus_type should not be modifying the
device that is passed into it, so mark it as a const * and propagate the
function signature changes out into all relevant subsystems that use
this callback.

Acked-by: Rafael J. Wysocki <[email protected]>
Acked-by: Hans de Goede <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: bus.h: document bus notifiers better

The bus notifier values are not documented all that well, so clean this
up and make a real enumerated type for them and document them much
better.

driver core: bus.h: document bus notifiers better

The bus notifier values are not documented all that well, so clean this
up and make a real enumerated type for them and document them much
better. When doing this, remove the hex values and just rely on the
enumerated type instead as that is all that is needed.

Reviewed-by: Randy Dunlap <[email protected]>
Reviewed-by: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: move struct subsys_dev_iter to a local file

struct subsys_dev_iter is not used by any code outside of
drivers/base/bus.c so move it into that file and out of the global bus.h
file.

Rev

driver core: move struct subsys_dev_iter to a local file

struct subsys_dev_iter is not used by any code outside of
drivers/base/bus.c so move it into that file and out of the global bus.h
file.

Reviewed-by: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver core: make subsys_dev_iter_exit() static

The function subsys_dev_iter_exit() is not used outside of
drivers/base/bus.c so make it static to that file and remove the global
export.

Reviewed-b

driver core: make subsys_dev_iter_exit() static

The function subsys_dev_iter_exit() is not used outside of
drivers/base/bus.c so make it static to that file and remove the global
export.

Reviewed-by: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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