[PATCH] s390: tape retry flooding by deferred CC in interrupt

If a deferred CC happens there will be lots of messages, because the retry is
done immediatly in the interrupt handler which can be too fast.  To avoid this
requeue the request and schedule the queue to be processed.

Signed-off-by: Stefan Bader <shbader@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/char/tape_core.c b/drivers/s390/char/tape_core.c
index 4ea438c749c9c6f4764ea1056c1baae1d1c52446..c42f5e25024efab3535094f593004b3180deea17 100644 (file)
--- a/drivers/s390/char/tape_core.c
+++ b/drivers/s390/char/tape_core.c
@@ -1064,15 +1064,16 @@ __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
        /*
         * If the condition code is not zero and the start function bit is
         * still set, this is an deferred error and the last start I/O did
-        * not succeed. Restart the request now.
+        * not succeed. At this point the condition that caused the deferred
+        * error might still apply. So we just schedule the request to be
+        * started later.
         */
        if (irb->scsw.cc != 0 && (irb->scsw.fctl & SCSW_FCTL_START_FUNC)) {
                PRINT_WARN("(%s): deferred cc=%i. restaring\n",
                        cdev->dev.bus_id,
                        irb->scsw.cc);
-               rc = __tape_start_io(device, request);
-               if (rc)
-                       __tape_end_request(device, request, rc);
+               request->status = TAPE_REQUEST_QUEUED;
+               schedule_work(&device->tape_dnr);
                return;
        }