From 71546300c8684eb69286604c79624582c16f2f5b Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Sat, 9 Mar 2013 08:16:47 +0000 Subject: [PATCH] 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 Reviewed-by: Jean Delvare Signed-off-by: Wolfram Sang --- 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 e4fe494..e9ac0d8 100644 --- 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 f2bcd46..e988fa9 100644 --- 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 *); -- 2.7.4