Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
driver core: bus: move dev_root out of struct bus_type
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>
+24
-8
+2
drivers/base/base.h
+2
drivers/base/base.h
···
27
27
* on this bus.
28
28
* @bus - pointer back to the struct bus_type that this structure is associated
29
29
* with.
30
+
* @dev_root: Default device to use as the parent.
30
31
*
31
32
* @glue_dirs - "glue" directory to put in-between the parent device to
32
33
* avoid namespace conflicts
···
50
49
struct blocking_notifier_head bus_notifier;
51
50
unsigned int drivers_autoprobe:1;
52
51
struct bus_type *bus;
52
+
struct device *dev_root;
53
53
54
54
struct kset glue_dirs;
55
55
struct class *class;
+22
-6
drivers/base/bus.c
+22
-6
drivers/base/bus.c
···
935
935
return;
936
936
937
937
pr_debug("bus: '%s': unregistering\n", bus->name);
938
-
if (bus->dev_root)
939
-
device_unregister(bus->dev_root);
938
+
if (sp->dev_root)
939
+
device_unregister(sp->dev_root);
940
940
941
941
bus_kobj = &sp->subsys.kobj;
942
942
sysfs_remove_groups(bus_kobj, bus->bus_groups);
···
1198
1198
const struct attribute_group **groups,
1199
1199
struct kobject *parent_of_root)
1200
1200
{
1201
+
struct subsys_private *sp;
1201
1202
struct device *dev;
1202
1203
int err;
1203
1204
1204
1205
err = bus_register(subsys);
1205
1206
if (err < 0)
1206
1207
return err;
1208
+
1209
+
sp = bus_to_subsys(subsys);
1210
+
if (!sp) {
1211
+
err = -EINVAL;
1212
+
goto err_sp;
1213
+
}
1207
1214
1208
1215
dev = kzalloc(sizeof(struct device), GFP_KERNEL);
1209
1216
if (!dev) {
···
1230
1223
if (err < 0)
1231
1224
goto err_dev_reg;
1232
1225
1233
-
subsys->dev_root = dev;
1226
+
sp->dev_root = dev;
1227
+
subsys_put(sp);
1234
1228
return 0;
1235
1229
1236
1230
err_dev_reg:
···
1240
1232
err_name:
1241
1233
kfree(dev);
1242
1234
err_dev:
1235
+
subsys_put(sp);
1236
+
err_sp:
1243
1237
bus_unregister(subsys);
1244
1238
return err;
1245
1239
}
···
1359
1349
*/
1360
1350
struct device *bus_get_dev_root(const struct bus_type *bus)
1361
1351
{
1362
-
if (bus)
1363
-
return get_device(bus->dev_root);
1364
-
return NULL;
1352
+
struct subsys_private *sp = bus_to_subsys(bus);
1353
+
struct device *dev_root;
1354
+
1355
+
if (!sp)
1356
+
return NULL;
1357
+
1358
+
dev_root = get_device(sp->dev_root);
1359
+
subsys_put(sp);
1360
+
return dev_root;
1365
1361
}
1366
1362
EXPORT_SYMBOL_GPL(bus_get_dev_root);
1367
1363
-2
include/linux/device/bus.h
-2
include/linux/device/bus.h
···
26
26
*
27
27
* @name: The name of the bus.
28
28
* @dev_name: Used for subsystems to enumerate devices like ("foo%u", dev->id).
29
-
* @dev_root: Default device to use as the parent.
30
29
* @bus_groups: Default attributes of the bus.
31
30
* @dev_groups: Default attributes of the devices on the bus.
32
31
* @drv_groups: Default attributes of the device drivers on the bus.
···
81
82
struct bus_type {
82
83
const char *name;
83
84
const char *dev_name;
84
-
struct device *dev_root;
85
85
const struct attribute_group **bus_groups;
86
86
const struct attribute_group **dev_groups;
87
87
const struct attribute_group **drv_groups;