s390/dasd: fix infinite loop during format

Error recovery requests may not be cleaned up correctly so that other
needed erp requests can not be build because of insufficient memory.
This would lead to an infinite loop trying to build erp requests.

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

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 5df05f26b7d9d966fc35a3fab397afbc33b53f7b..f0895f49d4f92eea6c9f7562ccb26a75bea0fb75 100644 (file)
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2261,8 +2261,8 @@ static inline int _wait_for_wakeup_queue(struct list_head *ccw_queue)
 static int _dasd_sleep_on_queue(struct list_head *ccw_queue, int interruptible)
 {
        struct dasd_device *device;
-       int rc;
        struct dasd_ccw_req *cqr, *n;
+       int rc;
 
 retry:
        list_for_each_entry_safe(cqr, n, ccw_queue, blocklist) {
@@ -2310,21 +2310,26 @@ retry:
                /*
                 * for alias devices simplify error recovery and
                 * return to upper layer
+                * do not skip ERP requests
                 */
-               if (cqr->startdev != cqr->basedev &&
+               if (cqr->startdev != cqr->basedev && !cqr->refers &&
                    (cqr->status == DASD_CQR_TERMINATED ||
                     cqr->status == DASD_CQR_NEED_ERP))
                        return -EAGAIN;
-               else {
-                       /* normal recovery for basedev IO */
-                       if (__dasd_sleep_on_erp(cqr)) {
-                               if (!cqr->status == DASD_CQR_TERMINATED &&
-                                   !cqr->status == DASD_CQR_NEED_ERP)
-                                       break;
-                               rc = 1;
-                       }
+
+               /* normal recovery for basedev IO */
+               if (__dasd_sleep_on_erp(cqr)) {
+                       goto retry;
+                       /* remember that ERP was needed */
+                       rc = 1;
+                       /* skip processing for active cqr */
+                       if (cqr->status != DASD_CQR_TERMINATED &&
+                           cqr->status != DASD_CQR_NEED_ERP)
+                               break;
                }
        }
+
+       /* start ERP requests in upper loop */
        if (rc)
                goto retry;