Return -1 in the error handling case instead of 0, as done elsewhere in
this function.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NMattia Dongili <malattia@linux.it>
Signed-off-by: NMatthew Garrett <matthew.garrett@nebula.com>