[PATCH] s390: fail-fast requests on quiesced devices

Using the fail-fast flag in i/o requests on a dasd disk which has been
quiesced leads to kernel panics.  Modify the request start function to only
work on requests in a valid state.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 170aae004ceb0b069354f4b79bb4348f98d19643..a3bfebcf31efeb72f3a6de690d82f412eaa5218b 100644 (file)
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1257,25 +1257,28 @@ __dasd_start_head(struct dasd_device * device)
        if (list_empty(&device->ccw_queue))
                return;
        cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, list);
-        /* check FAILFAST */
+       if (cqr->status != DASD_CQR_QUEUED)
+               return;
+       /* Non-temporary stop condition will trigger fail fast */
        if (device->stopped & ~DASD_STOPPED_PENDING &&
            test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
            (!dasd_eer_enabled(device))) {
                cqr->status = DASD_CQR_FAILED;
                dasd_schedule_bh(device);
+               return;
        }
-       if ((cqr->status == DASD_CQR_QUEUED) &&
-           (!device->stopped)) {
-               /* try to start the first I/O that can be started */
-               rc = device->discipline->start_IO(cqr);
-               if (rc == 0)
-                       dasd_set_timer(device, cqr->expires);
-               else if (rc == -EACCES) {
-                       dasd_schedule_bh(device);
-               } else
-                       /* Hmpf, try again in 1/2 sec */
-                       dasd_set_timer(device, 50);
-       }
+       /* Don't try to start requests if device is stopped */
+       if (device->stopped)
+               return;
+
+       rc = device->discipline->start_IO(cqr);
+       if (rc == 0)
+               dasd_set_timer(device, cqr->expires);
+       else if (rc == -EACCES) {
+               dasd_schedule_bh(device);
+       } else
+               /* Hmpf, try again in 1/2 sec */
+               dasd_set_timer(device, 50);
 }
 
 /*