[S390] dasd: prevent IO error during reserve/release loop

The termination of running CQR caused by reserve/release operations
may lead to an IO error if reserve/release is done in a tight loop.
Prevent this by increasing the retry counter after termination.

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

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 475e603fc584..86b6f1cc1b10 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1742,11 +1742,20 @@ int dasd_sleep_on_interruptible(struct dasd_ccw_req *cqr)
 static inline int _dasd_term_running_cqr(struct dasd_device *device)
 {
         struct dasd_ccw_req *cqr;
+        int rc;
 
         if (list_empty(&device->ccw_queue))
                 return 0;
         cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
-        return device->discipline->term_IO(cqr);
+        rc = device->discipline->term_IO(cqr);
+        if (!rc)
+                /*
+                 * CQR terminated because a more important request is pending.
+                 * Undo decreasing of retry counter because this is
+                 * not an error case.
+                 */
+                cqr->retries++;
+        return rc;
 }
 
 int dasd_sleep_on_immediatly(struct dasd_ccw_req *cqr)