[S390] dasd: add dynamic pav toleration

For base Parallel Access Volume (PAV) there is a fixed mapping of
base and alias devices. With dynamic PAV this mapping can be changed
so that an alias device is used with another base device.
This patch enables the DASD device driver to tolerate dynamic PAV
changes.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/drivers/s390/block/dasd_3990_erp.c b/drivers/s390/block/dasd_3990_erp.c
index 6632649dd6aa..85bfd8794856 100644
--- a/drivers/s390/block/dasd_3990_erp.c
+++ b/drivers/s390/block/dasd_3990_erp.c
@@ -1418,9 +1418,29 @@ static struct dasd_ccw_req *dasd_3990_erp_inspect_alias(
                                                 struct dasd_ccw_req *erp)
 {
         struct dasd_ccw_req *cqr = erp->refers;
+        char *sense;
 
         if (cqr->block &&
             (cqr->block->base != cqr->startdev)) {
+
+                sense = dasd_get_sense(&erp->refers->irb);
+                /*
+                 * dynamic pav may have changed base alias mapping
+                 */
+                if (!test_bit(DASD_FLAG_OFFLINE, &cqr->startdev->flags) && sense
+                    && (sense[0] == 0x10) && (sense[7] == 0x0F)
+                    && (sense[8] == 0x67)) {
+                        /*
+                         * remove device from alias handling to prevent new
+                         * requests from being scheduled on the
+                         * wrong alias device
+                         */
+                        dasd_alias_remove_device(cqr->startdev);
+
+                        /* schedule worker to reload device */
+                        dasd_reload_device(cqr->startdev);
+                }
+
                 if (cqr->startdev->features & DASD_FEATURE_ERPLOG) {
                         DBF_DEV_EVENT(DBF_ERR, cqr->startdev,
                                     "ERP on alias device for request %p,"