linux-stable.git/drivers/base/bus.c, branch linux-6.3.y

driver core: bus: Handle early calls to bus_to_subsys()

2023-02-25T09:51:21+00:00

When calling soc_device_match() from early_initcall(), bus_kset is still
NULL, causing a crash:

    Unable to handle kernel NULL pointer dereference at virtual address 0000000000000028
    ...
    Call trace:
     __lock_acquire+0x530/0x20f0
     lock_acquire.part.0+0xc8/0x210
     lock_acquire+0x64/0x80
     _raw_spin_lock+0x4c/0x60
     bus_to_subsys+0x24/0xac
     bus_for_each_dev+0x30/0xcc
     soc_device_match+0x4c/0xe0
     r8a7795_sysc_init+0x18/0x60
     rcar_sysc_pd_init+0xb0/0x33c
     do_one_initcall+0x128/0x2bc

Before, bus_for_each_dev() handled this gracefully by checking that
the back-pointer to the private structure was valid.

Fix this by adding a NULL check for bus_kset to bus_to_subsys().

Fixes: 83b9148df2c95e23 ("driver core: bus: bus iterator cleanups")
Signed-off-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/r/0a92979f6e790737544638e8a4c19b0564e660a2.1676983596.git.geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman

driver core: bus: update my copyright notice

2023-02-10T10:16:13+00:00

There's been some work done recently to the drivers/base/bus.c file so
update the copyright notice in it to make those who track those types of
things have an easier job.

Cc: "Rafael J. Wysocki" 
Link: https://lore.kernel.org/r/20230210091318.733561-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: bus: add bus_get_dev_root() function

2023-02-10T09:16:42+00:00

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" 
Link: https://lore.kernel.org/r/20230209093556.19132-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: bus: constify bus_unregister()

2023-02-09T09:43:45+00:00

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

Cc: "Rafael J. Wysocki" 
Link: https://lore.kernel.org/r/20230208111330.439504-22-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: bus: constify some internal functions

2023-02-09T09:43:43+00:00

The functions add_probe_files() and remove_probe_files() should be
taking a const * to bus_type, not just a *, so fix that up.  These
functions should really be removed entirely and an attribute group used
instead, but for now, make this change so that other const work can
continue.

Cc: "Rafael J. Wysocki" 
Link: https://lore.kernel.org/r/20230208111330.439504-21-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: bus: constify bus_get_kset()

2023-02-09T09:43:41+00:00

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

Cc: "Rafael J. Wysocki" 
Link: https://lore.kernel.org/r/20230208111330.439504-20-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: bus: constify bus_register/unregister_notifier()

2023-02-09T09:43:39+00:00

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" 
Link: https://lore.kernel.org/r/20230208111330.439504-19-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: remove private pointer from struct bus_type

2023-02-09T09:43:37+00:00

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" 
Link: https://lore.kernel.org/r/20230208111330.439504-18-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: create bus_is_registered()

2023-02-09T09:43:35+00:00

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" 
Link: https://lore.kernel.org/r/20230208111330.439504-17-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: bus: clean up driver_find()

2023-02-09T09:43:33+00:00

Convert the driver_find() function to use bus_to_subsys() and not use
the back-pointer to the private structure.

Cc: "Rafael J. Wysocki" 
Link: https://lore.kernel.org/r/20230208111330.439504-16-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman