s390/3215: fix hanging console issue

The ccw_device_start in raw3215_start_io can fail. raw3215_try_io
does not check if the request could be started and removes any
pending timer. This can leave the system in a hanging state.
Check for pending request after raw3215_start_io and start a
timer if necessary.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 17 insertions, 15 deletions

diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
index 5af7f0bd6125..a6d47e5eee9e 100644
--- a/drivers/s390/char/con3215.c
+++ b/drivers/s390/char/con3215.c
@@ -288,12 +288,16 @@ static void raw3215_timeout(unsigned long __data)
         unsigned long flags;
 
         spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags);
-        if (raw->flags & RAW3215_TIMER_RUNS) {
-                del_timer(&raw->timer);
-                raw->flags &= ~RAW3215_TIMER_RUNS;
-                if (!(raw->port.flags & ASYNC_SUSPENDED)) {
-                        raw3215_mk_write_req(raw);
-                        raw3215_start_io(raw);
+        raw->flags &= ~RAW3215_TIMER_RUNS;
+        if (!(raw->port.flags & ASYNC_SUSPENDED)) {
+                raw3215_mk_write_req(raw);
+                raw3215_start_io(raw);
+                if ((raw->queued_read || raw->queued_write) &&
+                    !(raw->flags & RAW3215_WORKING) &&
+                    !(raw->flags & RAW3215_TIMER_RUNS)) {
+                        raw->timer.expires = RAW3215_TIMEOUT + jiffies;
+                        add_timer(&raw->timer);
+                        raw->flags |= RAW3215_TIMER_RUNS;
                 }
         }
         spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);
@@ -317,17 +321,15 @@ static inline void raw3215_try_io(struct raw3215_info *raw)
                     (raw->flags & RAW3215_FLUSHING)) {
                         /* execute write requests bigger than minimum size */
                         raw3215_start_io(raw);
-                        if (raw->flags & RAW3215_TIMER_RUNS) {
-                                del_timer(&raw->timer);
-                                raw->flags &= ~RAW3215_TIMER_RUNS;
-                        }
-                } else if (!(raw->flags & RAW3215_TIMER_RUNS)) {
-                        /* delay small writes */
-                        raw->timer.expires = RAW3215_TIMEOUT + jiffies;
-                        add_timer(&raw->timer);
-                        raw->flags |= RAW3215_TIMER_RUNS;
                 }
         }
+        if ((raw->queued_read || raw->queued_write) &&
+            !(raw->flags & RAW3215_WORKING) &&
+            !(raw->flags & RAW3215_TIMER_RUNS)) {
+                raw->timer.expires = RAW3215_TIMEOUT + jiffies;
+                add_timer(&raw->timer);
+                raw->flags |= RAW3215_TIMER_RUNS;
+        }
 }
 
 /*