idr_pre_get
int idr_pre_get(struct idr *idp, gfp_t gfp_mask);
if (idr_pre_get(&ida->idr, flags) == 0)
if (!idr_pre_get(idr, lock ? GFP_KERNEL : GFP_ATOMIC))
if (!idr_pre_get(&dev->qpidr, GFP_KERNEL)) {