[SCSI] hpsa: fix physical device lun and target numbering problem

If a physical device exposed to the OS by hpsa
is replaced (e.g. one hot plug tape drive is replaced
by another, or a tape drive is placed into "OBDR" mode
in which it acts like a CD-ROM device) and a rescan is
initiated, the replaced device will be added to the
SCSI midlayer with target and lun numbers set to -1.
After that, a panic is likely to ensue.  When a physical
device is replaced, the lun and target number should be
preserved.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Cc: stable@kernel.org
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 1f32f0610bc0..b200b736b000 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -676,6 +676,16 @@ static void hpsa_scsi_replace_entry(struct ctlr_info *h, int hostno,
         BUG_ON(entry < 0 || entry >= HPSA_MAX_SCSI_DEVS_PER_HBA);
         removed[*nremoved] = h->dev[entry];
         (*nremoved)++;
+
+        /*
+         * New physical devices won't have target/lun assigned yet
+         * so we need to preserve the values in the slot we are replacing.
+         */
+        if (new_entry->target == -1) {
+                new_entry->target = h->dev[entry]->target;
+                new_entry->lun = h->dev[entry]->lun;
+        }
+
         h->dev[entry] = new_entry;
         added[*nadded] = new_entry;
         (*nadded)++;