On Sat, 9 Mar 2013 19:16:47 +0100, Lars-Peter Clausen wrote: > 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 <[email protected]> > --- > drivers/i2c/i2c-core.c | 6 ++---- > include/linux/i2c.h | 2 +- > 2 files changed, 3 insertions(+), 5 deletions(-) > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > index 7727d33..838d030 100644 > --- a/drivers/i2c/i2c-core.c > +++ b/drivers/i2c/i2c-core.c > @@ -1060,7 +1060,7 @@ 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; > @@ -1072,7 +1072,7 @@ 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 */ > @@ -1124,8 +1124,6 @@ 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 8ffab3f..dec1702 100644 > --- a/include/linux/i2c.h > +++ b/include/linux/i2c.h > @@ -447,7 +447,7 @@ 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 *);
Reviewed-by: Jean Delvare <[email protected]> -- Jean Delvare -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
