linux-toradex.git/drivers/base/bus.c, branch v6.7-rc8

driver core: bus: constify bus_get()

2023-03-23T12:21:24+00:00

It's funny to think about getting a reference count of a constant
structure pointer, but this locks into place the private data
"underneath" the struct bus_type() which is important to not go away
while we are working with the bus structure for some callbacks.

Cc: "Rafael J. Wysocki" 
Link: https://lore.kernel.org/r/20230313182918.1312597-27-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: bus: constify driver_find()

2023-03-23T12:21:22+00:00

The driver_find() 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/20230313182918.1312597-26-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: bus: constify bus_rescan_devices()

2023-03-23T12:21:20+00:00

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" 
Link: https://lore.kernel.org/r/20230313182918.1312597-25-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: bus: constantify bus_register()

2023-03-23T12:21:17+00:00

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" 
Link: https://lore.kernel.org/r/20230313182918.1312597-24-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

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

2023-03-23T12:20:40+00:00

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" 
Cc: "James E.J. Bottomley" 
Cc: "K. Y. Srinivasan" 
Cc: Alexander Gordeev 
Cc: Alexandre Bounine 
Cc: Alison Schofield 
Cc: Ben Widawsky 
Cc: Dexuan Cui 
Cc: Eric Dumazet 
Cc: Haiyang Zhang 
Cc: Hannes Reinecke 
Cc: Harald Freudenberger 
Cc: Heiko Carstens 
Cc: Hu Haowen 
Cc: Jakub Kicinski 
Cc: Jens Axboe 
Cc: Jonathan Corbet 
Cc: Laurentiu Tudor 
Cc: Matt Porter 
Cc: Michael Ellerman 
Cc: Paolo Abeni 
Cc: Stuart Yoder 
Cc: Vasily Gorbik 
Cc: Vishal Verma 
Cc: Yanteng Si 
Acked-by: Ilya Dryomov  # rbd
Acked-by: Ira Weiny  # cxl
Reviewed-by: Alex Shi 
Acked-by: Iwona Winiarska 
Acked-by: Dan Williams 
Acked-by: Bjorn Helgaas 	# pci
Acked-by: Wei Liu 
Acked-by: Martin K. Petersen  # scsi
Link: https://lore.kernel.org/r/20230313182918.1312597-23-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

driver core: bus: move dev_root out of struct bus_type

2023-03-23T12:20:36+00:00

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" 
Link: https://lore.kernel.org/r/20230313182918.1312597-22-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

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