[Xen-devel] [PATCH 3/3] xen-blkfront: Fix minor offset calculation for emulated IDE disks

[Stefan Bader <stefan.bader@xxxxxxxxxxxxx>]

Before this a block device defined as hda1 in the configuration files
would be mapped to hda, as well as hda2.

Signed-off-by: Stefan Bader <stefan.bader@xxxxxxxxxxxxx>
---
 drivers/block/xen-blkfront.c |   12 +++++++-----
 1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 6e46edb..77489f1 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -449,15 +449,17 @@ static int xen_translate_vdev(int vdevice, int *minor, 
unsigned int *offset)
        major = BLKIF_MAJOR(vdevice);
        *minor = BLKIF_MINOR(vdevice);
        switch (major) {
+               /* For IDE the assumption seems to be 64 partitions (including
+                * the whole device) per disk. */
                case XEN_IDE0_MAJOR:
                        *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET;
-                       *minor = ((*minor / 64) * PARTS_PER_DISK) +
-                               EMULATED_HD_DISK_MINOR_OFFSET;
+                       *minor = *minor + EMULATED_HD_DISK_MINOR_OFFSET;
                        break;
                case XEN_IDE1_MAJOR:
-                       *offset = (*minor / 64) + 2 + 
EMULATED_HD_DISK_NAME_OFFSET;
-                       *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) +
-                               EMULATED_HD_DISK_MINOR_OFFSET;
+                       *offset = (*minor / 64) + 2 +
+                                 EMULATED_HD_DISK_NAME_OFFSET;
+                       *minor = *minor + (2 * 64) +
+                                EMULATED_HD_DISK_MINOR_OFFSET;
                        break;
                case XEN_SCSI_DISK0_MAJOR:
                        *offset = (*minor / PARTS_PER_DISK) + 
EMULATED_SD_DISK_NAME_OFFSET;
-- 
1.7.4.1


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