[S390] tape: fix race with stack local wait_queue_head_t.
A wait_event call with a stack local wait_queue_head_t structure that is
used to do the wake up for the wait_event is inherently racy. After the
wait_event finished the wake_up call might not have completed yet.
Replace the stack local wait_queue_head_t in tape_do_io and
tape_do_io_interruptible with a per device wait queue.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/char/tape.h b/drivers/s390/char/tape.h
index dddf8d6..d0d565a 100644
--- a/drivers/s390/char/tape.h
+++ b/drivers/s390/char/tape.h
@@ -231,6 +231,9 @@
/* Request queue. */
struct list_head req_queue;
+ /* Request wait queue. */
+ wait_queue_head_t wait_queue;
+
/* Each tape device has (currently) two minor numbers. */
int first_minor;