linux-stable.git/drivers/base/bus.c, branch v6.14

driver core: Introduce device_iter_t for device iterating APIs

2025-01-10T14:26:12+00:00

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 
Signed-off-by: Zijun Hu 
Link: https://lore.kernel.org/r/20250105-class_fix-v6-7-3a2f1768d4d4@quicinc.com
Signed-off-by: Greg Kroah-Hartman

driver core: Move true expression out of if condition in 3 device finding APIs

2025-01-10T14:26:12+00:00

For bus_find_device(), driver_find_device(), and device_find_child(), all
of their function body have pattern below:

{
	struct klist_iter i;
	struct device *dev;

	...
	while ((dev = next_device(&i)))
		if (match(dev, data) && get_device(dev))
			break;
	...
}

The expression 'get_device(dev)' in the if condition always returns true
since @dev != NULL.

Move the expression to if body to make logic of these APIs more clearer.

Reviewed-by: Fan Ni 
Reviewed-by: Jonathan Cameron 
Signed-off-by: Zijun Hu 
Link: https://lore.kernel.org/r/20250105-class_fix-v6-3-3a2f1768d4d4@quicinc.com
Signed-off-by: Greg Kroah-Hartman

drivers/base: Introduce device_match_t for device finding APIs

2024-09-03T10:48:51+00:00

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 
Link: https://lore.kernel.org/r/20240813-dev_match_api-v3-1-6c6878a99b9f@quicinc.com
Signed-off-by: Greg Kroah-Hartman

driver core: bus: Fix double free in driver API bus_register()

2024-07-31T12:55:49+00:00

For bus_register(), any error which happens after kset_register() will
cause that @priv are freed twice, fixed by setting @priv with NULL after
the first free.

Signed-off-by: Zijun Hu 
Link: https://lore.kernel.org/r/20240727-bus_register_fix-v1-1-fed8dd0dba7a@quicinc.com
Signed-off-by: Greg Kroah-Hartman

driver core: bus: Add simple error handling for buses_init()

2024-07-31T12:55:40+00:00

Add simple error handling for buses_init() since it is easy to do.

Signed-off-by: Zijun Hu 
Link: https://lore.kernel.org/r/20240727-buses_init-v1-1-e863295a2c0e@quicinc.com
Signed-off-by: Greg Kroah-Hartman

driver core: Remove unused parameter for virtual_device_parent()

2024-07-31T12:55:13+00:00

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 
Link: https://lore.kernel.org/r/20240725-virtual_kobj_fix-v1-1-36335cae4544@quicinc.com
Signed-off-by: Greg Kroah-Hartman

driver core: bus: Return -EIO instead of 0 when show/store invalid bus attribute

2024-07-31T12:54:55+00:00

Return -EIO instead of 0 for below erroneous bus attribute operations:
 - read a bus attribute without show().
 - write a bus attribute without store().

Signed-off-by: Zijun Hu 
Link: https://lore.kernel.org/r/20240724-bus_fix-v2-1-5adbafc698fb@quicinc.com
Signed-off-by: Greg Kroah-Hartman

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