exfat_blk_readahead
exfat_blk_readahead(sb, sector + i, &ra, &ra_cnt, end);
exfat_blk_readahead(sb, sec, &ra, &cnt, sec + ra_count - 1);
int exfat_blk_readahead(struct super_block *sb, sector_t sec,
exfat_blk_readahead(sb, sec, &ra, &ra_cnt, end);