[PATCH v2 1/1] mcb: create dedicated bus_type for mcb_bus and mcb_device

Rodríguez Barbarin, José Javier
2023-08-18T11:04:08Z

When allocating a new mcb_bus the bus_type is added to the mcb_bus
itself, causing an issue when calling mcb_bus_add_devices().
This function is not only called for each mcb_device under the
mcb_bus but for the bus itself.

This causes a crash when freeing the ida resources as the bus numbering
gets corrupted due to a wrong cast of structs mcb_bus and mcb_device.

Make the release of the mcb devices and their mcb bus explicit.

Fixes: 18d288198099 ("mcb: Correctly initialize the bus's device")
Co-developed-by: Jorge Sanjuan Garcia <jorge.sanjuangarcia@duagon.com>
Signed-off-by: Jorge Sanjuan Garcia <jorge.sanjuangarcia@duagon.com>
Signed-off-by: Jose Javier Rodriguez Barbarin <JoseJavier.Rodriguez@duagon.com>
---
drivers/mcb/mcb-core.c | 43 ++++++++++++++++++++++++++++++++++++------
1 file changed, 37 insertions(+), 6 deletions(-)

diff --git a/drivers/mcb/mcb-core.c b/drivers/mcb/mcb-core.c
index 978fdfc19a06..d2ac2a12b737 100644
--- a/drivers/mcb/mcb-core.c
+++ b/drivers/mcb/mcb-core.c
@@ -156,7 +156,7 @@ static const struct attribute_group *mcb_carrier_groups[] = {
};

-static struct bus_type mcb_bus_type = {
+static struct bus_type mcb_device_type = {
.name = "mcb",
.match = mcb_match,
.uevent = mcb_uevent,
@@ -165,6 +165,11 @@ static struct bus_type mcb_bus_type = {
.shutdown = mcb_shutdown,
};

+static struct bus_type mcb_bus_type = {
+ .name = "mcb-bus",
+ .dev_name = "mcb-bus",
+};
+
static struct device_type mcb_carrier_device_type = {
.name = "mcb-carrier",
.groups = mcb_carrier_groups,
@@ -186,7 +191,7 @@ int __mcb_register_driver(struct mcb_driver *drv, struct module *owner,
return -EINVAL;

drv->driver.owner = owner;
- drv->driver.bus = &mcb_bus_type;
+ drv->driver.bus = &mcb_device_type;
drv->driver.mod_name = mod_name;

return driver_register(&drv->driver);
@@ -227,7 +232,7 @@ int mcb_device_register(struct mcb_bus *bus, struct mcb_device *dev)

device_initialize(&dev->dev);
mcb_bus_get(bus);
- dev->dev.bus = &mcb_bus_type;
+ dev->dev.bus = &mcb_device_type;
dev->dev.parent = bus->dev.parent;
dev->dev.release = mcb_release_dev;
dev->dma_dev = bus->carrier;
@@ -251,6 +256,12 @@ int mcb_device_register(struct mcb_bus *bus, struct mcb_device *dev)
}
EXPORT_SYMBOL_NS_GPL(mcb_device_register, MCB);

+
+static void mcb_bus_unregister(struct mcb_bus *bus)
+{
+ device_unregister(&bus->dev);
+}
+
static void mcb_free_bus(struct device *dev)
{
struct mcb_bus *bus = to_mcb_bus(dev);
@@ -311,7 +322,7 @@ static int __mcb_devices_unregister(struct device *dev, void *data)

static void mcb_devices_unregister(struct mcb_bus *bus)
{
- bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_devices_unregister);
+ bus_for_each_dev(&mcb_device_type, NULL, NULL, __mcb_devices_unregister);
}
/**
* mcb_release_bus() - Free a @mcb_bus
@@ -322,6 +333,7 @@ static void mcb_devices_unregister(struct mcb_bus *bus)
void mcb_release_bus(struct mcb_bus *bus)
{
mcb_devices_unregister(bus);
+ mcb_bus_unregister(bus);
}
EXPORT_SYMBOL_NS_GPL(mcb_release_bus, MCB);

@@ -410,7 +422,7 @@ static int __mcb_bus_add_devices(struct device *dev, void *data)
*/
void mcb_bus_add_devices(const struct mcb_bus *bus)
{
- bus_for_each_dev(&mcb_bus_type, NULL, NULL, __mcb_bus_add_devices);
+ bus_for_each_dev(&mcb_device_type, NULL, NULL, __mcb_bus_add_devices);
}
EXPORT_SYMBOL_NS_GPL(mcb_bus_add_devices, MCB);

@@ -499,12 +511,31 @@ EXPORT_SYMBOL_NS_GPL(mcb_get_irq, MCB);

static int mcb_init(void)
{
- return bus_register(&mcb_bus_type);
+ int res;
+
+ res = bus_register(&mcb_bus_type);
+
+ if (res < 0)
+ goto mcb_bus_register_fail;
+
+ res = bus_register(&mcb_device_type);
+
+ if (res < 0)
+ goto mcb_device_register_fail;
+
+ return 0;
+
+mcb_device_register_fail:
+ bus_unregister(&mcb_bus_type);
+
+mcb_bus_register_fail:
+ return res;
}

static void mcb_exit(void)
{
ida_destroy(&mcb_ida);
+ bus_unregister(&mcb_device_type);
bus_unregister(&mcb_bus_type);
}

--
2.34.1