cciss: add support for multi lun tape devices

This patch adds support for multi-lun devices in a SAS environment. It's
required for the support of media changers.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cca.cpqcorp.net>
Signed-off-by: Mike Miller <mike.miller@hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/drivers/block/cciss_scsi.c b/drivers/block/cciss_scsi.c
index c673ff14126a7e07126c29101db096aeb778f4b3..e1233aabda771493718b5f37f9228e00301098e3 100644 (file)
--- a/drivers/block/cciss_scsi.c
+++ b/drivers/block/cciss_scsi.c
@@ -371,16 +371,50 @@ cciss_scsi_add_entry(int ctlr, int hostno,
        /* assumes hba[ctlr]->scsi_ctlr->lock is held */ 
        int n = ccissscsi[ctlr].ndevices;
        struct cciss_scsi_dev_t *sd;
+       int i, bus, target, lun;
+       unsigned char addr1[8], addr2[8];
 
        if (n >= CCISS_MAX_SCSI_DEVS_PER_HBA) {
                printk("cciss%d: Too many devices, "
                        "some will be inaccessible.\n", ctlr);
                return -1;
        }
-       sd = &ccissscsi[ctlr].dev[n];
-       if (find_bus_target_lun(ctlr, &sd->bus, &sd->target, &sd->lun) != 0)
-               return -1;
 
+       bus = target = -1;
+       lun = 0;
+       /* Is this device a non-zero lun of a multi-lun device */
+       /* byte 4 of the 8-byte LUN addr will contain the logical unit no. */
+       if (scsi3addr[4] != 0) {
+               /* Search through our list and find the device which */
+               /* has the same 8 byte LUN address, excepting byte 4. */
+               /* Assign the same bus and target for this new LUN. */
+               /* Use the logical unit number from the firmware. */
+               memcpy(addr1, scsi3addr, 8);
+               addr1[4] = 0;
+               for (i = 0; i < n; i++) {
+                       sd = &ccissscsi[ctlr].dev[i];
+                       memcpy(addr2, sd->scsi3addr, 8);
+                       addr2[4] = 0;
+                       /* differ only in byte 4? */
+                       if (memcmp(addr1, addr2, 8) == 0) {
+                               bus = sd->bus;
+                               target = sd->target;
+                               lun = scsi3addr[4];
+                               break;
+                       }
+               }
+       }
+
+       sd = &ccissscsi[ctlr].dev[n];
+       if (lun == 0) {
+               if (find_bus_target_lun(ctlr,
+                       &sd->bus, &sd->target, &sd->lun) != 0)
+                       return -1;
+       } else {
+               sd->bus = bus;
+               sd->target = target;
+               sd->lun = lun;
+       }
        added[*nadded].bus = sd->bus;
        added[*nadded].target = sd->target;
        added[*nadded].lun = sd->lun;