i2c: Make return type of i2c_del_adapter() void

i2c_del_adapter() is usually called from a drivers remove callback. The Linux
device driver model does not allow the remove callback to fail and all resources
allocated in the probe callback need to be freed, as well as all resources which
have been provided to the rest of the kernel(for example a I2C adapter) need to
be revoked. So any function revoking such resources isn't allowed to fail
either. i2c_del_adapter() adheres to this requirement and will never fail. But
i2c_del_adapter()'s return type is int, which may cause driver authors to think
that it can fail. This led to code constructs like:

	ret = i2c_del_adapter(...);
	BUG_ON(ret);

Since i2c_del_adapter() always returns 0 the BUG_ON is never hit and essentially
becomes dead code, which means it can be removed. Making the return type of
i2c_del_adapter() void makes it explicit that the function will never fail and
should prevent constructs like the above from re-appearing in the kernel code.

All callers of i2c_del_adapter() have already been updated in a previous patch
to ignore the return value, so the conversion of the return type from int to
void can be done without causing any build failures.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index e4fe4940fd826b302c8ab4662488b62491346598..e9ac0d84a01ea8cc32c56422295752b4dd049dc1 100644 (file)
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1219,7 +1219,7 @@ static int __process_removed_adapter(struct device_driver *d, void *data)
  * This unregisters an I2C adapter which was previously registered
  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
  */
-int i2c_del_adapter(struct i2c_adapter *adap)
+void i2c_del_adapter(struct i2c_adapter *adap)
 {
        struct i2c_adapter *found;
        struct i2c_client *client, *next;
@@ -1231,7 +1231,7 @@ int i2c_del_adapter(struct i2c_adapter *adap)
        if (found != adap) {
                pr_debug("i2c-core: attempting to delete unregistered "
                         "adapter [%s]\n", adap->name);
-               return 0;
+               return;
        }
 
        /* Tell drivers about this removal */
@@ -1283,8 +1283,6 @@ int i2c_del_adapter(struct i2c_adapter *adap)
        /* Clear the device structure in case this adapter is ever going to be
           added again */
        memset(&adap->dev, 0, sizeof(adap->dev));
-
-       return 0;
 }
 EXPORT_SYMBOL(i2c_del_adapter);
 

diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index f2bcd46ce194d7fa1ec0f9a82d57352f6a5a44c0..e988fa935b3c4ad22e5a6e47e8f4ccea0f0e1c3d 100644 (file)
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -488,7 +488,7 @@ void i2c_unlock_adapter(struct i2c_adapter *);
  */
 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 extern int i2c_add_adapter(struct i2c_adapter *);
-extern int i2c_del_adapter(struct i2c_adapter *);
+extern void i2c_del_adapter(struct i2c_adapter *);
 extern int i2c_add_numbered_adapter(struct i2c_adapter *);
 
 extern int i2c_register_driver(struct module *, struct i2c_driver *);