[S390] zcrypt: fix possible dead lock in AP bus module

AP bus module uses bus_for_each_dev() in software interrupt context to
poll for completed requests which might cause dead locks. Solution: use
private AP device list for polling in software interrupt context.

Signed-off-by: Ralph Wuerthner <rwuerthn@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h
index 83b69c0..008559e 100644
--- a/drivers/s390/crypto/ap_bus.h
+++ b/drivers/s390/crypto/ap_bus.h
@@ -106,6 +106,7 @@
 	struct device device;
 	struct ap_driver *drv;		/* Pointer to AP device driver. */
 	spinlock_t lock;		/* Per device lock. */
+	struct list_head list;		/* private list of all AP devices. */
 
 	ap_qid_t qid;			/* AP queue id. */
 	int queue_depth;		/* AP queue depth.*/