[S390] dasd: fix endless loop in erp

If not enough memory is available to build a new erp request it ended
up in an endless loop trying to build erp requests. Fixed the loop to
proceed the next request instead.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/block/dasd.c

@@ -1899,7 +1899,8 @@ restart:
 		/*  Process requests that may be recovered */
 		if (cqr->status == DASD_CQR_NEED_ERP) {
 			erp_fn = base->discipline->erp_action(cqr);
-			erp_fn(cqr);
+			if (IS_ERR(erp_fn(cqr)))
+				continue;
 			goto restart;
 		}
 

drivers/s390/block/dasd_3990_erp.c

@@ -2309,7 +2309,7 @@ static struct dasd_ccw_req *dasd_3990_erp_add_erp(struct dasd_ccw_req *cqr)
                                      cqr->retries);
 			dasd_block_set_timer(device->block, (HZ << 3));
                 }
-		return cqr;
+		return erp;
 	}
 
 	ccw = cqr->cpaddr;
@@ -2372,6 +2372,9 @@ dasd_3990_erp_additional_erp(struct dasd_ccw_req * cqr)
 	/* add erp and initialize with default TIC */
 	erp = dasd_3990_erp_add_erp(cqr);
 
+	if (IS_ERR(erp))
+		return erp;
+
 	/* inspect sense, determine specific ERP if possible */
 	if (erp != cqr) {
 
@@ -2711,6 +2714,8 @@ dasd_3990_erp_action(struct dasd_ccw_req * cqr)
 	if (erp == NULL) {
 		/* no matching erp found - set up erp */
 		erp = dasd_3990_erp_additional_erp(cqr);
+		if (IS_ERR(erp))
+			return erp;
 	} else {
 		/* matching erp found - set all leading erp's to DONE */
 		erp = dasd_3990_erp_handle_match_erp(cqr, erp);