[SCSI] avoid overflows in disk size calculations

Be more careful about doing the arithmetic in the non-LBD case.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 9a1dc0cea03c..98da5c8057bf 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1253,14 +1253,13 @@ got_data:
                  * Jacques Gelinas (Jacques@solucorp.qc.ca)
                  */
                 int hard_sector = sector_size;
-                sector_t sz = sdkp->capacity * (hard_sector/256);
+                sector_t sz = (sdkp->capacity/2) * (hard_sector/256);
                 request_queue_t *queue = sdp->request_queue;
-                sector_t mb;
+                sector_t mb = sz;
 
                 blk_queue_hardsect_size(queue, hard_sector);
                 /* avoid 64-bit division on 32-bit platforms */
-                mb = sz >> 1;
-                sector_div(sz, 1250);
+                sector_div(sz, 625);
                 mb -= sz - 974;
                 sector_div(mb, 1950);