[S390] cio: improve error recovery for internal I/Os

Improve error recovery for internal I/Os by repeating each I/O
256 times per path to cope with long-running non-permanent error
conditions. Also retry each path twice to cope with link flapping,
i.e. single paths becoming unavailable in the order in which they
are tried.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/ccwreq.c

@@ -82,7 +82,7 @@ static void ccwreq_do(struct ccw_device *cdev)
 		/* Perform start function. */
 		sch->lpm = 0xff;
 		memset(&cdev->private->irb, 0, sizeof(struct irb));
-		rc = cio_start(sch, cp, req->mask);
+		rc = cio_start(sch, cp, (u8) req->mask);
 		if (rc == 0) {
 			/* I/O started successfully. */
 			ccw_device_set_timeout(cdev, req->timeout);
@@ -116,7 +116,8 @@ void ccw_request_start(struct ccw_device *cdev)
 {
 	struct ccw_request *req = &cdev->private->req;
 
-	req->mask	= 0x80;
+	/* Try all paths twice to counter link flapping. */
+	req->mask	= 0x8080;
 	req->retries	= req->maxretries;
 	req->mask	= lpm_adjust(req->mask, req->lpm);
 	req->drc	= 0;
@@ -212,7 +213,7 @@ static void ccwreq_log_status(struct ccw_device *cdev, enum io_status status)
 	}  __attribute__ ((packed)) data;
 	data.dev_id	= cdev->private->dev_id;
 	data.retries	= req->retries;
-	data.lpm	= req->mask;
+	data.lpm	= (u8) req->mask;
 	data.status	= (u8) status;
 	CIO_TRACE_EVENT(2, "reqstat");
 	CIO_HEX_EVENT(2, &data, sizeof(data));

drivers/s390/cio/device_id.c

@@ -21,7 +21,7 @@
 #include "device.h"
 #include "io_sch.h"
 
-#define SENSE_ID_RETRIES	5
+#define SENSE_ID_RETRIES	256
 #define SENSE_ID_TIMEOUT	(10 * HZ)
 #define SENSE_ID_MIN_LEN	4
 #define SENSE_ID_BASIC_LEN	7

drivers/s390/cio/device_pgid.c

@@ -20,7 +20,7 @@
 #include "device.h"
 #include "io_sch.h"
 
-#define PGID_RETRIES	5
+#define PGID_RETRIES	256
 #define PGID_TIMEOUT	(10 * HZ)
 
 /*

drivers/s390/cio/io_sch.h

@@ -109,7 +109,7 @@ struct ccw_request {
 	void (*callback)(struct ccw_device *, void *, int);
 	void *data;
 	/* These fields are used internally. */
-	u8 mask;
+	u16 mask;
 	u16 retries;
 	int drc;
 	int cancel:1;