Man page 9 : blkdev_issue_flush

blkdev_issue_flush - queue a flush

int blkdev_issue_flush(struct block_device *  bdev , gfp_t  gfp_mask , sector_t *  error_sector );

bdev
    blockdev to issue flush for

gfp_mask
    memory allocation flags (for bio_alloc)

error_sector
    error sector

Issue a flush for the block device in question. Caller can supply room for storing the error offset in case of a flush error, if they wish to. If WAIT flag is not passed then caller may check only what request was pushed in some internal queue for later handling.