SATA_DISK_SECTOR_SIZE
rval = SATA_DISK_SECTOR_SIZE; /* fixed size */
xfer_len *= SATA_DISK_SECTOR_SIZE;
xfer_len *= SATA_DISK_SECTOR_SIZE;
if ((bp->b_bcount % SATA_DISK_SECTOR_SIZE) != 0)
sector_count = bp->b_bcount / SATA_DISK_SECTOR_SIZE;