static sector_t calc_num_sectors(mdk_rdev_t *rdev, unsigned chunk_size)
 {
-       sector_t num_sectors = rdev->sb_offset * 2;
+       sector_t num_sectors = rdev->sb_start;
 
        if (chunk_size)
                num_sectors &= ~((sector_t)chunk_size/512 - 1);
                put_page(rdev->sb_page);
                rdev->sb_loaded = 0;
                rdev->sb_page = NULL;
-               rdev->sb_offset = 0;
+               rdev->sb_start = 0;
                rdev->size = 0;
        }
 }
                return 0;
 
 
-       if (!sync_page_io(rdev->bdev, rdev->sb_offset<<1, size, rdev->sb_page, READ))
+       if (!sync_page_io(rdev->bdev, rdev->sb_start, size, rdev->sb_page, READ))
                goto fail;
        rdev->sb_loaded = 1;
        return 0;
        char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
        mdp_super_t *sb;
        int ret;
-       sector_t sb_offset;
 
        /*
-        * Calculate the position of the superblock,
+        * Calculate the position of the superblock (512byte sectors),
         * it's at the end of the disk.
         *
         * It also happens to be a multiple of 4Kb.
         */
-       sb_offset = calc_dev_sboffset(rdev->bdev) / 2;
-       rdev->sb_offset = sb_offset;
+       rdev->sb_start = calc_dev_sboffset(rdev->bdev);
 
        ret = read_disk_sb(rdev, MD_SB_BYTES);
        if (ret) return ret;
        size *= 2; /* convert to sectors */
        if (rdev->mddev->bitmap_offset)
                return 0; /* can't move bitmap */
-       rdev->sb_offset = calc_dev_sboffset(rdev->bdev) / 2;
-       if (!size || size > rdev->sb_offset*2)
-               size = rdev->sb_offset*2;
-       md_super_write(rdev->mddev, rdev, rdev->sb_offset << 1, rdev->sb_size,
+       rdev->sb_start = calc_dev_sboffset(rdev->bdev);
+       if (!size || size > rdev->sb_start)
+               size = rdev->sb_start;
+       md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
                       rdev->sb_page);
        md_super_wait(rdev->mddev);
        return size/2; /* kB for sysfs */
 {
        struct mdp_superblock_1 *sb;
        int ret;
-       sector_t sb_offset;
+       sector_t sb_start;
        char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
        int bmask;
 
        /*
-        * Calculate the position of the superblock.
+        * Calculate the position of the superblock in 512byte sectors.
         * It is always aligned to a 4K boundary and
         * depeding on minor_version, it can be:
         * 0: At least 8K, but less than 12K, from end of device
         */
        switch(minor_version) {
        case 0:
-               sb_offset = rdev->bdev->bd_inode->i_size >> 9;
-               sb_offset -= 8*2;
-               sb_offset &= ~(sector_t)(4*2-1);
-               /* convert from sectors to K */
-               sb_offset /= 2;
+               sb_start = rdev->bdev->bd_inode->i_size >> 9;
+               sb_start -= 8*2;
+               sb_start &= ~(sector_t)(4*2-1);
                break;
        case 1:
-               sb_offset = 0;
+               sb_start = 0;
                break;
        case 2:
-               sb_offset = 4;
+               sb_start = 8;
                break;
        default:
                return -EINVAL;
        }
-       rdev->sb_offset = sb_offset;
+       rdev->sb_start = sb_start;
 
        /* superblock is rarely larger than 1K, but it can be larger,
         * and it is safe to read 4k, so we do that
        if (sb->magic != cpu_to_le32(MD_SB_MAGIC) ||
            sb->major_version != cpu_to_le32(1) ||
            le32_to_cpu(sb->max_dev) > (4096-256)/2 ||
-           le64_to_cpu(sb->super_offset) != (rdev->sb_offset<<1) ||
+           le64_to_cpu(sb->super_offset) != rdev->sb_start ||
            (le32_to_cpu(sb->feature_map) & ~MD_FEATURE_ALL) != 0)
                return -EINVAL;
 
                rdev->sb_size = (rdev->sb_size | bmask) + 1;
 
        if (minor_version
-           && rdev->data_offset < sb_offset + (rdev->sb_size/512))
+           && rdev->data_offset < sb_start + (rdev->sb_size/512))
                return -EINVAL;
 
        if (sb->level == cpu_to_le32(LEVEL_MULTIPATH))
        if (minor_version)
                rdev->size = ((rdev->bdev->bd_inode->i_size>>9) - le64_to_cpu(sb->data_offset)) / 2;
        else
-               rdev->size = rdev->sb_offset;
+               rdev->size = rdev->sb_start / 2;
        if (rdev->size < le64_to_cpu(sb->data_size)/2)
                return -EINVAL;
        rdev->size = le64_to_cpu(sb->data_size)/2;
        if (size && size < rdev->mddev->size)
                return 0; /* component must fit device */
        size *= 2; /* convert to sectors */
-       if (rdev->sb_offset < rdev->data_offset/2) {
+       if (rdev->sb_start < rdev->data_offset) {
                /* minor versions 1 and 2; superblock before data */
                max_size = (rdev->bdev->bd_inode->i_size >> 9);
                max_size -= rdev->data_offset;
                return 0;
        } else {
                /* minor version 0; superblock after data */
-               sector_t sb_offset;
-               sb_offset = (rdev->bdev->bd_inode->i_size >> 9) - 8*2;
-               sb_offset &= ~(sector_t)(4*2 - 1);
-               max_size = rdev->size*2 + sb_offset - rdev->sb_offset*2;
+               sector_t sb_start;
+               sb_start = (rdev->bdev->bd_inode->i_size >> 9) - 8*2;
+               sb_start &= ~(sector_t)(4*2 - 1);
+               max_size = rdev->size*2 + sb_start - rdev->sb_start;
                if (!size || size > max_size)
                        size = max_size;
-               rdev->sb_offset = sb_offset/2;
+               rdev->sb_start = sb_start;
        }
        sb = (struct mdp_superblock_1 *) page_address(rdev->sb_page);
        sb->data_size = cpu_to_le64(size);
-       sb->super_offset = rdev->sb_offset*2;
+       sb->super_offset = rdev->sb_start;
        sb->sb_csum = calc_sb_1_csum(sb);
-       md_super_write(rdev->mddev, rdev, rdev->sb_offset << 1, rdev->sb_size,
+       md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
                       rdev->sb_page);
        md_super_wait(rdev->mddev);
        return size/2; /* kB for sysfs */
                dprintk("%s ", bdevname(rdev->bdev,b));
                if (!test_bit(Faulty, &rdev->flags)) {
                        md_super_write(mddev,rdev,
-                                      rdev->sb_offset<<1, rdev->sb_size,
+                                      rdev->sb_start, rdev->sb_size,
                                       rdev->sb_page);
                        dprintk(KERN_INFO "(write) %s's sb offset: %llu\n",
                                bdevname(rdev->bdev,b),
-                               (unsigned long long)rdev->sb_offset);
+                               (unsigned long long)rdev->sb_start);
                        rdev->sb_events = mddev->events;
 
                } else
                 * We don't want the data to overlap the metadata,
                 * Internal Bitmap issues has handled elsewhere.
                 */
-               if (rdev->data_offset < rdev->sb_offset) {
+               if (rdev->data_offset < rdev->sb_start) {
                        if (mddev->size &&
                            rdev->data_offset + mddev->size*2
-                           > rdev->sb_offset*2) {
+                           > rdev->sb_start) {
                                printk("md: %s: data overlaps metadata\n",
                                       mdname(mddev));
                                return -EINVAL;
                        }
                } else {
-                       if (rdev->sb_offset*2 + rdev->sb_size/512
+                       if (rdev->sb_start + rdev->sb_size/512
                            > rdev->data_offset) {
                                printk("md: %s: metadata overlaps data\n",
                                       mdname(mddev));
 
                if (!mddev->persistent) {
                        printk(KERN_INFO "md: nonpersistent superblock ...\n");
-                       rdev->sb_offset = rdev->bdev->bd_inode->i_size >> BLOCK_SIZE_BITS;
+                       rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
                } else 
-                       rdev->sb_offset = calc_dev_sboffset(rdev->bdev) / 2;
+                       rdev->sb_start = calc_dev_sboffset(rdev->bdev);
                rdev->size = calc_num_sectors(rdev, mddev->chunk_size) / 2;
 
                err = bind_rdev_to_array(rdev, mddev);
        }
 
        if (mddev->persistent)
-               rdev->sb_offset = calc_dev_sboffset(rdev->bdev) / 2;
+               rdev->sb_start = calc_dev_sboffset(rdev->bdev);
        else
-               rdev->sb_offset =
-                       rdev->bdev->bd_inode->i_size >> BLOCK_SIZE_BITS;
+               rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
 
        rdev->size = calc_num_sectors(rdev, mddev->chunk_size) / 2;
 
         * linear and raid0 always use whatever space is available. We can only
         * consider changing this number if no resync or reconstruction is
         * happening, and if the new size is acceptable. It must fit before the
-        * sb_offset or, if that is <data_offset, it must fit before the size
+        * sb_start or, if that is <data_offset, it must fit before the size
         * of each device.  If num_sectors is zero, we find the largest size
         * that fits.