CALLOUT_MPSAFE
callout_init(&sc->re_stat_ch, CALLOUT_MPSAFE);
if (c->flags & CALLOUT_MPSAFE) {
cc->flags = CALLOUT_DID_INIT | CALLOUT_MPSAFE;
cc->flags = CALLOUT_DID_INIT | CALLOUT_MPSAFE | CALLOUT_AUTOLOCK;
cc->flags = CALLOUT_DID_INIT | CALLOUT_MPSAFE;
callout_init(&priv->exp_callout, CALLOUT_MPSAFE);