->add_dev() may fail and the error returned from it can be useful for
the caller.
For example, if some of the resources aren't ready yet and -EPROBE_DEFER
is returned from ->add_dev(), then the owner of 'struct
subsys_interface' may want to try probing again at a later point of
time. And that requires a proper return value from ->add_dev().
Also, if we hit an error while registering subsys_interface, then we
should stop proceeding further and rollback whatever has been done until
then. Break part of subsys_interface_unregister() into another routine,
which lets us call ->remove_dev() for all devices for which ->add_dev()
is already called.
Cc: 3.3+ <stable@xxxxxxxxxxxxxxx> # 3.3+
Fixes: ca22e56debc5 ("driver-core: implement 'sysdev' functionality for regular devices and buses")
Reported-and-tested-by: Pi-Cheng Chen <pi-cheng.chen@xxxxxxxxxx>
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
drivers/base/bus.c | 55 ++++++++++++++++++++++++++++++++++--------------------
1 file changed, 35 insertions(+), 20 deletions(-)
diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 79bc203f51ef..d92dc109ba51 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -1112,11 +1112,36 @@ void subsys_dev_iter_exit(struct subsys_dev_iter *iter)
}
EXPORT_SYMBOL_GPL(subsys_dev_iter_exit);
+static void __subsys_interface_unregister(struct subsys_interface *sif,
+ struct device *lastdev)
+{
+ struct bus_type *subsys = sif->subsys;
+ struct subsys_dev_iter iter;
+ struct device *dev;
+
+ mutex_lock(&subsys->p->mutex);
+ list_del_init(&sif->node);
+ if (sif->remove_dev) {
+ subsys_dev_iter_init(&iter, subsys, NULL, NULL);
+ while ((dev = subsys_dev_iter_next(&iter))) {
+ if (dev == lastdev)
+ break;
+
+ sif->remove_dev(dev, sif);
+ }
+ subsys_dev_iter_exit(&iter);
+ }
+ mutex_unlock(&subsys->p->mutex);
+
+ bus_put(subsys);
+}
+
int subsys_interface_register(struct subsys_interface *sif)
{
struct bus_type *subsys;
struct subsys_dev_iter iter;
struct device *dev;
+ int ret = 0;
if (!sif || !sif->subsys)
return -ENODEV;
@@ -1129,38 +1154,28 @@ int subsys_interface_register(struct subsys_interface *sif)
list_add_tail(&sif->node, &subsys->p->interfaces);
if (sif->add_dev) {
subsys_dev_iter_init(&iter, subsys, NULL, NULL);
- while ((dev = subsys_dev_iter_next(&iter)))
- sif->add_dev(dev, sif);
+ while ((dev = subsys_dev_iter_next(&iter))) {
+ ret = sif->add_dev(dev, sif);
+ if (ret)
+ break;
+ }
subsys_dev_iter_exit(&iter);
}
mutex_unlock(&subsys->p->mutex);
- return 0;
+ if (ret)
+ __subsys_interface_unregister(sif, dev);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(subsys_interface_register);
void subsys_interface_unregister(struct subsys_interface *sif)
{
- struct bus_type *subsys;
- struct subsys_dev_iter iter;
- struct device *dev;
-
if (!sif || !sif->subsys)
return;
- subsys = sif->subsys;
-
- mutex_lock(&subsys->p->mutex);
- list_del_init(&sif->node);
- if (sif->remove_dev) {
- subsys_dev_iter_init(&iter, subsys, NULL, NULL);
- while ((dev = subsys_dev_iter_next(&iter)))
- sif->remove_dev(dev, sif);
- subsys_dev_iter_exit(&iter);
- }
- mutex_unlock(&subsys->p->mutex);
-
- bus_put(subsys);
+ __subsys_interface_unregister(sif, NULL);
}
EXPORT_SYMBOL_GPL(subsys_interface_unregister);
--
2.4.0
--
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