linux-stable.git/drivers/base/bus.c, branch linux-6.10.y

module: don't ignore sysfs_create_link() failures

2024-04-11T12:42:08+00:00

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 
Reviewed-by: Luis Chamberlain 
Link: https://lore.kernel.org/r/20240408080616.3911573-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman

driver core: bus: constantify subsys_register() calls

2023-12-21T12:55:38+00:00

The functions subsys_register() and subsys_virtual_register() should be
taking a constant pointer to a struct bus_type, as they do not actually
modify anything in it, so fix up the function definitions to do so
properly.

This also changes the pointer type in struct subsys_interface to be
constant as well, as again, that's the proper signature of it.

Cc: Rafael J. Wysocki 
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/2023121908-grove-genetics-f8af@gregkh
Signed-off-by: Greg Kroah-Hartman

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

2023-12-21T12:55:08+00:00

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 
Link: https://lore.kernel.org/r/2023121935-stinking-ditzy-fd5d@gregkh
Signed-off-by: Greg Kroah-Hartman

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