iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

driver core: bus: move dev_root out of struct bus_type

Browse Source 
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" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230313182918.1312597-22-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Greg Kroah-Hartman 2023-03-13 19:29:04 +01:00
parent bf6479dbe7
commit 9cc61e5fbd
3 changed files with 24 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/base/base.h
View File

@ -27,6 +27,7 @@
* on this bus.
* @bus - pointer back to the struct bus_type that this structure is associated
* with.
* @dev_root: Default device to use as the parent.
*
* @glue_dirs - "glue" directory to put in-between the parent device to
* avoid namespace conflicts
@ -49,6 +50,7 @@ struct subsys_private {
struct blocking_notifier_head bus_notifier;
unsigned int drivers_autoprobe:1;
struct bus_type *bus;
struct device *dev_root;
struct kset glue_dirs;
struct class *class;

28
drivers/base/bus.c
View File

@ -935,8 +935,8 @@ void bus_unregister(const struct bus_type *bus)
return;
pr_debug("bus: '%s': unregistering\n", bus->name);
if (bus->dev_root)
device_unregister(bus->dev_root);
if (sp->dev_root)
device_unregister(sp->dev_root);
bus_kobj = &sp->subsys.kobj;
sysfs_remove_groups(bus_kobj, bus->bus_groups);
@ -1198,6 +1198,7 @@ static int subsys_register(struct bus_type *subsys,
const struct attribute_group **groups,
struct kobject *parent_of_root)
{
struct subsys_private *sp;
struct device *dev;
int err;
@ -1205,6 +1206,12 @@ static int subsys_register(struct bus_type *subsys,
if (err < 0)
return err;
sp = bus_to_subsys(subsys);
if (!sp) {
err = -EINVAL;
goto err_sp;
}
dev = kzalloc(sizeof(struct device), GFP_KERNEL);
if (!dev) {
err = -ENOMEM;
@ -1223,7 +1230,8 @@ static int subsys_register(struct bus_type *subsys,
if (err < 0)
goto err_dev_reg;
subsys->dev_root = dev;
sp->dev_root = dev;
subsys_put(sp);
return 0;
err_dev_reg:
@ -1232,6 +1240,8 @@ err_dev_reg:
err_name:
kfree(dev);
err_dev:
subsys_put(sp);
err_sp:
bus_unregister(subsys);
return err;
}
@ -1349,9 +1359,15 @@ bool bus_is_registered(const struct bus_type *bus)
*/
struct device *bus_get_dev_root(const struct bus_type *bus)
{
if (bus)
return get_device(bus->dev_root);
return NULL;
struct subsys_private *sp = bus_to_subsys(bus);
struct device *dev_root;
if (!sp)
return NULL;
dev_root = get_device(sp->dev_root);
subsys_put(sp);
return dev_root;
}
EXPORT_SYMBOL_GPL(bus_get_dev_root);

2
include/linux/device/bus.h
View File

@ -26,7 +26,6 @@ struct fwnode_handle;
*
* @name: The name of the bus.
* @dev_name: Used for subsystems to enumerate devices like ("foo%u", dev->id).
* @dev_root: Default device to use as the parent.
* @bus_groups: Default attributes of the bus.
* @dev_groups: Default attributes of the devices on the bus.
* @drv_groups: Default attributes of the device drivers on the bus.
@ -82,7 +81,6 @@ struct fwnode_handle;
struct bus_type {
const char *name;
const char *dev_name;
struct device *dev_root;
const struct attribute_group **bus_groups;
const struct attribute_group **dev_groups;
const struct attribute_group **drv_groups;