PATCH: Support tera byte disk

H. J. Lu (hjl@lucon.org)
Wed, 18 Sep 2002 13:11:20 -0700


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For a 1.8TB SCSI HD, kernel reports:

SCSI device sda: -773086208 512-byte hdwr sectors (-395819 MB)

Here is a patch to fix it. BTW, I don't think it will work with > 2TB,
which requires bigger changes.

H.J.

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--- linux-2.4.18-14.2/drivers/scsi/sd.c.tera Wed Sep 18 11:55:53 2002
+++ linux-2.4.18-14.2/drivers/scsi/sd.c Wed Sep 18 12:42:36 2002
@@ -1018,8 +1018,16 @@ static int sd_init_onedisk(int i)
* Jacques Gelinas (Jacques@solucorp.qc.ca)
*/
int m;
- int hard_sector = sector_size;
- int sz = rscsi_disks[i].capacity * (hard_sector/256);
+ unsigned hard_sector = sector_size;
+ unsigned sz = rscsi_disks[i].capacity * (hard_sector/256);
+
+ /* Check for overflow. */
+ if (sz < rscsi_disks[i].capacity) {
+ sz = (rscsi_disks[i].capacity/1950) * (hard_sector/256);
+ sz = sz/2 - sz/1250 + 974;
+ }
+ else
+ sz = (sz/2 - sz/1250 + 974)/1950;

/* There are 16 minors allocated for each major device */
for (m = i << 4; m < ((i + 1) << 4); m++) {
@@ -1027,9 +1035,9 @@ static int sd_init_onedisk(int i)
}

printk("SCSI device %s: "
- "%d %d-byte hdwr sectors (%d MB)\n",
+ "%u %u-byte hdwr sectors (%u MB)\n",
nbuff, rscsi_disks[i].capacity,
- hard_sector, (sz/2 - sz/1250 + 974)/1950);
+ hard_sector, sz);
}

/* Rescale capacity to 512-byte units */

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