BLK_FEAT_IO_STAT
lim->features |= BLK_FEAT_IO_STAT | BLK_FEAT_NOWAIT;
QUEUE_SYSFS_FEATURE(iostats, BLK_FEAT_IO_STAT)
limits->features |= BLK_FEAT_IO_STAT | BLK_FEAT_NOWAIT | BLK_FEAT_POLL;
BLK_FEAT_IO_STAT | BLK_FEAT_NOWAIT;
lim.features |= BLK_FEAT_IO_STAT | BLK_FEAT_NOWAIT |
#define blk_queue_io_stat(q) ((q)->limits.features & BLK_FEAT_IO_STAT)