s390/cio: recover from bad paths

In some situations we don't receive notification from firmware that
a previously unusable channelpath is usable again.

Schedule recovery for devices that return from path verification
without using all potentially usable paths. The recovery thread will
periodically trigger a path verification on the affected devices.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Suggested-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/io_sch.h b/drivers/s390/cio/io_sch.h
index 220f491..9a1b56b 100644
--- a/drivers/s390/cio/io_sch.h
+++ b/drivers/s390/cio/io_sch.h
@@ -131,6 +131,8 @@
 				   not operable */
 	u8 path_gone_mask;	/* mask of paths, that became unavailable */
 	u8 path_new_mask;	/* mask of paths, that became available */
+	u8 path_broken_mask;	/* mask of paths, which were found to be
+				   unusable */
 	struct {
 		unsigned int fast:1;	/* post with "channel end" */
 		unsigned int repall:1;	/* report every interrupt status */