Re: [PATCH] usb: ulpi: don't register drivers if bus doesn't exist

Sudip Mukherjee
2015-05-28T05:39:53Z

On Wed, May 27, 2015 at 08:21:16AM -0700, Greg KH wrote:
> On Wed, May 27, 2015 at 11:16:34AM -0400, Alan Stern wrote:
> > On Wed, 27 May 2015, Heikki Krogerus wrote:
>
> Maybe we need to test for this in the driver core, not allowing drivers
> for busses that are not registered, that might solve the main problem
> here. I'll try to look at it tonight.
may i suggest something like this ?
buildtest with allmodconfig and allyesconfig on x86_64.
built and booted on x86.

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 5005924..95cefa0 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -943,6 +943,7 @@ int bus_register(struct bus_type *bus)
if (retval)
goto bus_groups_fail;

+ bus->registered = true;
pr_debug("bus: '%s': registered\n", bus->name);
return 0;

diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index 4eabfe2..1acae5b 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -150,6 +150,11 @@ int driver_register(struct device_driver *drv)
int ret;
struct device_driver *other;

+ if (!drv->bus->registered) {
+ pr_err("Driver %s registration failed. bus not yet registered\n",
+ drv->name);
+ return -ENODEV;
+ }
BUG_ON(!drv->bus->p);

if ((drv->bus->probe && drv->probe) ||
diff --git a/include/linux/device.h b/include/linux/device.h
index 00ac57c..8fe4745 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -126,6 +126,7 @@ struct bus_type {
const struct dev_pm_ops *pm;

const struct iommu_ops *iommu_ops;
+ bool registered; /* DON'T TOUCH THIS */

struct subsys_private *p;
struct lock_class_key lock_key;

regards
sudip
>
> thanks,
>
> greg k-h