#define gen_for_each_lun(bm, lun, i) \
for ((i) = 0, lun = &(bm)->luns[0]; \
(i) < (bm)->nr_luns; (i)++, lun = &(bm)->luns[(i)])
#define gen_for_each_lun(bm, lun, i) \
for ((i) = 0, lun = &(bm)->luns[0]; \
(i) < (bm)->nr_luns; (i)++, lun = &(bm)->luns[(i)])