[S390] cio: Try harder to disable subchannel.

Acting upon the assumption that cio_disable_subchannel()
is only called when we really want to disable the subchannel
(a) remove the check for activity (it is already done in
    ccw_device_offline(), which is the place where it matters)
(b) collect pending status via tsch() and ignore it (it
    can't matter anymore since the subchannel will be disabled).

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 11 insertions, 9 deletions

diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index 73135c5e9dfb..2aebb9823044 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -472,6 +472,7 @@ EXPORT_SYMBOL_GPL(cio_enable_subchannel);
 int cio_disable_subchannel(struct subchannel *sch)
 {
         char dbf_txt[15];
+        int retry;
         int ret;
 
         CIO_TRACE_EVENT (2, "dissch");
@@ -482,16 +483,17 @@ int cio_disable_subchannel(struct subchannel *sch)
         if (cio_update_schib(sch))
                 return -ENODEV;
 
-        if (scsw_actl(&sch->schib.scsw) != 0)
-                /*
-                 * the disable function must not be called while there are
-                 *  requests pending for completion !
-                 */
-                return -EBUSY;
-
         sch->config.ena = 0;
-        ret = cio_commit_config(sch);
 
+        for (retry = 0; retry < 3; retry++) {
+                ret = cio_commit_config(sch);
+                if (ret == -EBUSY) {
+                        struct irb irb;
+                        if (tsch(sch->schid, &irb) != 0)
+                                break;
+                } else
+                        break;
+        }
         sprintf (dbf_txt, "ret:%d", ret);
         CIO_TRACE_EVENT (2, dbf_txt);
         return ret;
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index 95f2f352cb9d..301d27bf944e 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -1052,7 +1052,7 @@ ccw_device_offline_irq(struct ccw_device *cdev, enum dev_event dev_event)
         sch = to_subchannel(cdev->dev.parent);
         /*
          * An interrupt in state offline means a previous disable was not
-         * successful. Try again.
+         * successful - should not happen, but we try to disable again.
          */
         cio_disable_subchannel(sch);
 }