[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>

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 475e603fc584f8547e6171eaf8cdb325ec085d1f..86b6f1cc1b10c56277f49ec439b893daf2c25f33 100644 (file)
--- 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)