Types of some fields, variables and parameters of some functions should be
unsigned.

Link: https://lore.kernel.org/r/1607650657-35992-10-git-send-email-liweihang@huawei.comSigned-off-by: Wenpeng Liang <liangwenpeng@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>