GC_SECTORS_USED_SIZE  215 drivers/md/bcache/bcache.h #define MAX_GC_SECTORS_USED	(~(~0ULL << GC_SECTORS_USED_SIZE))
GC_SECTORS_USED_SIZE  216 drivers/md/bcache/bcache.h BITMASK(GC_SECTORS_USED, struct bucket, gc_mark, 2, GC_SECTORS_USED_SIZE);