s390/cio: improve cio_commit_config

The modify subchannel wrapper cio_commit_config can fail when
(unexpected) status is pending on the subchannel.

Callers of cio_commit_config (that operated on enabled subchannels)
needed to do error handling for that case (clear the unexpected
status with test subchannel and retry). This error handling is
missing in some code paths and caused online setting of devices to
fail.

Fix this for all callers by moving the error handling inside
cio_commit_config.
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/cio.c

@@ -342,8 +342,9 @@ static int cio_check_config(struct subchannel *sch, struct schib *schib)
  */
 int cio_commit_config(struct subchannel *sch)
 {
-	struct schib schib;
 	int ccode, retry, ret = 0;
+	struct schib schib;
+	struct irb irb;
 
 	if (stsch_err(sch->schid, &schib) || !css_sch_is_valid(&schib))
 		return -ENODEV;
@@ -367,7 +368,10 @@ int cio_commit_config(struct subchannel *sch)
 			ret = -EAGAIN;
 			break;
 		case 1: /* status pending */
-			return -EBUSY;
+			ret = -EBUSY;
+			if (tsch(sch->schid, &irb))
+				return ret;
+			break;
 		case 2: /* busy */
 			udelay(100); /* allow for recovery */
 			ret = -EBUSY;
@@ -403,7 +407,6 @@ EXPORT_SYMBOL_GPL(cio_update_schib);
  */
 int cio_enable_subchannel(struct subchannel *sch, u32 intparm)
 {
-	int retry;
 	int ret;
 
 	CIO_TRACE_EVENT(2, "ensch");
@@ -418,20 +421,14 @@ int cio_enable_subchannel(struct subchannel *sch, u32 intparm)
 	sch->config.isc = sch->isc;
 	sch->config.intparm = intparm;
 
-	for (retry = 0; retry < 3; retry++) {
+	ret = cio_commit_config(sch);
+	if (ret == -EIO) {
+		/*
+		 * Got a program check in msch. Try without
+		 * the concurrent sense bit the next time.
+		 */
+		sch->config.csense = 0;
 		ret = cio_commit_config(sch);
-		if (ret == -EIO) {
-			/*
-			 * Got a program check in msch. Try without
-			 * the concurrent sense bit the next time.
-			 */
-			sch->config.csense = 0;
-		} else if (ret == -EBUSY) {
-			struct irb irb;
-			if (tsch(sch->schid, &irb) != 0)
-				break;
-		} else
-			break;
 	}
 	CIO_HEX_EVENT(2, &ret, sizeof(ret));
 	return ret;
@@ -444,7 +441,6 @@ EXPORT_SYMBOL_GPL(cio_enable_subchannel);
  */
 int cio_disable_subchannel(struct subchannel *sch)
 {
-	int retry;
 	int ret;
 
 	CIO_TRACE_EVENT(2, "dissch");
@@ -456,16 +452,8 @@ int cio_disable_subchannel(struct subchannel *sch)
 		return -ENODEV;
 
 	sch->config.ena = 0;
+	ret = cio_commit_config(sch);
 
-	for (retry = 0; retry < 3; retry++) {
-		ret = cio_commit_config(sch);
-		if (ret == -EBUSY) {
-			struct irb irb;
-			if (tsch(sch->schid, &irb) != 0)
-				break;
-		} else
-			break;
-	}
 	CIO_HEX_EVENT(2, &ret, sizeof(ret));
 	return ret;
 }