[S390] cio: Use path verification for last path gone after vary off.

If the last path to a device is gone after a chpid has been varied
off, putting it on the slow queue doesn't prevent a device driver
from still attempting to use it (it may stay on the slow queue for a
long time). Instead, trigger a verify event which will prevent I/O
attempts from the device driver immediately.

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

3 files changed, 24 insertions, 10 deletions

diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index 9d92540bd99e..11900de94cb3 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -744,20 +744,22 @@ __s390_subchannel_vary_chpid(struct subchannel *sch, __u8 chpid, int on)
                                 device_trigger_reprobe(sch);
                         else if (sch->driver && sch->driver->verify)
                                 sch->driver->verify(&sch->dev);
-                } else {
-                        sch->opm &= ~(0x80 >> chp);
-                        sch->lpm &= ~(0x80 >> chp);
-                        if (check_for_io_on_path(sch, chp))
-                                /* Path verification is done after killing. */
-                                device_kill_io(sch);
-                        else if (!sch->lpm) {
+                        break;
+                }
+                sch->opm &= ~(0x80 >> chp);
+                sch->lpm &= ~(0x80 >> chp);
+                if (check_for_io_on_path(sch, chp))
+                        /* Path verification is done after killing. */
+                        device_kill_io(sch);
+                else if (!sch->lpm) {
+                        if (device_trigger_verify(sch) != 0) {
                                 if (css_enqueue_subchannel_slow(sch->schid)) {
                                         css_clear_subchannel_slow_list();
                                         need_rescan = 1;
                                 }
-                        } else if (sch->driver && sch->driver->verify)
-                                sch->driver->verify(&sch->dev);
-                }
+                        }
+                } else if (sch->driver && sch->driver->verify)
+                        sch->driver->verify(&sch->dev);
                 break;
         }
         spin_unlock_irqrestore(&sch->lock, flags);
diff --git a/drivers/s390/cio/css.h b/drivers/s390/cio/css.h
index 4c2ff8336288..da73453fa54b 100644
--- a/drivers/s390/cio/css.h
+++ b/drivers/s390/cio/css.h
@@ -171,6 +171,7 @@ void device_trigger_reprobe(struct subchannel *);
 /* Helper functions for vary on/off. */
 int device_is_online(struct subchannel *);
 void device_kill_io(struct subchannel *);
+int device_trigger_verify(struct subchannel *sch);
 
 /* Machine check helper function. */
 void device_kill_pending_timer(struct subchannel *);
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index de3d0857db9f..7665000e8dfe 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -59,6 +59,17 @@ device_set_disconnected(struct subchannel *sch)
         cdev->private->state = DEV_STATE_DISCONNECTED;
 }
 
+int device_trigger_verify(struct subchannel *sch)
+{
+        struct ccw_device *cdev;
+
+        cdev = sch->dev.driver_data;
+        if (!cdev || !cdev->online)
+                return -EINVAL;
+        dev_fsm_event(cdev, DEV_EVENT_VERIFY);
+        return 0;
+}
+
 /*
  * Timeout function. It just triggers a DEV_EVENT_TIMEOUT.
  */