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driver core: create bus_is_registered()

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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" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230208111330.439504-17-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Greg Kroah-Hartman 2023-02-08 12:13:25 +01:00
parent fb451966ae
commit 63b823d7d3
3 changed files with 18 additions and 1 deletions
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1
drivers/base/base.h
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@ -146,6 +146,7 @@ extern int bus_add_device(struct device *dev);
extern void bus_probe_device(struct device *dev);
extern void bus_remove_device(struct device *dev);
void bus_notify(struct device *dev, enum bus_notifier_event value);
bool bus_is_registered(const struct bus_type *bus);
extern int bus_add_driver(struct device_driver *drv);
extern void bus_remove_driver(struct device_driver *drv);

16
drivers/base/bus.c
View file

@ -1322,6 +1322,22 @@ struct device_driver *driver_find(const char *name, struct bus_type *bus)
}
EXPORT_SYMBOL_GPL(driver_find);
/*
* Warning, the value could go to "removed" instantly after calling this function, so be very
* careful when calling it...
*/
bool bus_is_registered(const struct bus_type *bus)
{
struct subsys_private *sp = bus_to_subsys(bus);
bool is_initialized = false;
if (sp) {
is_initialized = true;
subsys_put(sp);
}
return is_initialized;
}
int __init buses_init(void)
{
bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);

2
drivers/base/driver.c
View file

@ -224,7 +224,7 @@ int driver_register(struct device_driver *drv)
int ret;
struct device_driver *other;
if (!drv->bus->p) {
if (!bus_is_registered(drv->bus)) {
pr_err("Driver '%s' was unable to register with bus_type '%s' because the bus was not initialized.\n",
drv->name, drv->bus->name);
return -EINVAL;