SR_REBUILD_IO_SIZE
whole_blk = sd->sd_meta->ssdi.ssd_size / SR_REBUILD_IO_SIZE;
partial_blk = sd->sd_meta->ssdi.ssd_size % SR_REBUILD_IO_SIZE;
restart = sd->sd_meta->ssd_rebuild / SR_REBUILD_IO_SIZE;
buf = dma_alloc(SR_REBUILD_IO_SIZE << DEV_BSHIFT, PR_WAITOK);
lba = blk * SR_REBUILD_IO_SIZE;
sz = SR_REBUILD_IO_SIZE;
dma_free(buf, SR_REBUILD_IO_SIZE << DEV_BSHIFT);