MCTP_TAG_MASK
const u8 tagbits = MCTP_TAG_MASK | MCTP_TAG_OWNER |
if ((ctl.tag & ~MCTP_TAG_MASK) != (MCTP_TAG_OWNER | MCTP_TAG_PREALLOC))
tag = ctl.tag & MCTP_TAG_MASK;
BUILD_BUG_ON(MCTP_TAG_MASK != MCTP_HDR_TAG_MASK);
tag = req_tag & MCTP_TAG_MASK;