The return values of some functions have been modified,
but the comments have not been modified together. The
comments must be updated to be consistent with the functions.

Also move comments over the codes instead of right place
to ensure consistent coding styles.
Signed-off-by: Weili Qian <qianweili@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>