i2c: Guard against oopses from bad init sequences
Guard I2C against oopsing because of init sequence problems, by
verifying that i2c_init() has been called before calling any
routines that rely on that initialization. This specific test
just requires that bus_register(&i2c_bus_type) was called.
Examples of this kind of oopsing come from subystems and drivers
which register I2C drivers in their subsys_initcall code but
which are statically linked before I2C by drivers/Makefile.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index b346a68..a96e1bf 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -437,6 +437,10 @@
{
int res = 0, dummy;
+ /* Can't register until after driver model init */
+ if (unlikely(WARN_ON(!i2c_bus_type.p)))
+ return -EAGAIN;
+
mutex_init(&adap->bus_lock);
mutex_init(&adap->clist_lock);
INIT_LIST_HEAD(&adap->clients);
@@ -696,6 +700,10 @@
{
int res;
+ /* Can't register until after driver model init */
+ if (unlikely(WARN_ON(!i2c_bus_type.p)))
+ return -EAGAIN;
+
/* new style driver methods can't mix with legacy ones */
if (is_newstyle_driver(driver)) {
if (driver->attach_adapter || driver->detach_adapter