SWP_TB_FLAGS_BITS
BUILD_BUG_ON(SWP_TB_FLAGS_BITS > BITS_PER_BYTE);
VM_WARN_ON(flags >> SWP_TB_FLAGS_BITS);
(BITS_PER_LONG - SWAP_CACHE_PFN_MARK_BITS - SWP_TB_FLAGS_BITS));
#define SWP_TB_COUNT_BITS (SWP_TB_FLAGS_BITS - SWAP_TABLE_HAS_ZEROFLAG)
#define SWP_TB_FLAGS_MASK (~((~0UL) >> SWP_TB_FLAGS_BITS))
#define SWP_TB_FLAGS_SHIFT (BITS_PER_LONG - SWP_TB_FLAGS_BITS)
#define SWP_TB_ZERO_FLAG BIT(BITS_PER_LONG - SWP_TB_FLAGS_BITS)
#define SWAP_COUNT_SHIFT SWP_TB_FLAGS_BITS