SB_NR_TO_BIT
nr = SB_NR_TO_BIT(sb, start);
set_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr));
clear_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr));
set_bit(SB_NR_TO_BIT(sb, bitnr), addr);
return test_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr));
alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
mask |= (1UL << SB_NR_TO_BIT(sb, tag));