[S390] path grouping and path verifications fixes.

1. Multipath devices for which SetPGID is not supported are not handled well.
   Use NOP ccws for path verification (sans path grouping) when SetPGID is not
   supported.
2. Check for PGIDs already set with SensePGID on _all_ paths (not just the
   first one) and try to find a common one. Moan if no common PGID can be
   found (and use NOP verification). If no PGIDs have been set, use the css
   global PGID (as before). (Rationale: SetPGID will get a command reject if
   the PGID it tries to set does not match the already set PGID.)
3. Immediately before reboot, issue RESET CHANNEL PATH (rcp) on all chpids. This
   will remove the old PGIDs. rcp will generate solicited CRWs which can be
   savely ignored by the machine check handler (all other actions create
   unsolicited CRWs).

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 99 insertions, 23 deletions

diff --git a/drivers/s390/cio/device_pgid.c b/drivers/s390/cio/device_pgid.c
index 54cb64ed0786..32610fd8868e 100644
--- a/drivers/s390/cio/device_pgid.c
+++ b/drivers/s390/cio/device_pgid.c
@@ -33,12 +33,17 @@ __ccw_device_sense_pgid_start(struct ccw_device *cdev)
 	struct subchannel *sch;
 	struct ccw1 *ccw;
 	int ret;
+	int i;
 
 	sch = to_subchannel(cdev->dev.parent);
+	/* Return if we already checked on all paths. */
+	if (cdev->private->imask == 0)
+		return (sch->lpm == 0) ? -ENODEV : -EACCES;
+	i = 8 - ffs(cdev->private->imask);
+
 	/* Setup sense path group id channel program. */
 	ccw = cdev->private->iccws;
 	ccw->cmd_code = CCW_CMD_SENSE_PGID;
-	ccw->cda = (__u32) __pa (&cdev->private->pgid);
 	ccw->count = sizeof (struct pgid);
 	ccw->flags = CCW_FLAG_SLI;
 
@@ -48,6 +53,7 @@ __ccw_device_sense_pgid_start(struct ccw_device *cdev)
 	ret = -ENODEV;
 	while (cdev->private->imask != 0) {
 		/* Try every path multiple times. */
+		ccw->cda = (__u32) __pa (&cdev->private->pgid[i]);
 		if (cdev->private->iretry > 0) {
 			cdev->private->iretry--;
 			ret = cio_start (sch, cdev->private->iccws, 
@@ -64,7 +70,9 @@ __ccw_device_sense_pgid_start(struct ccw_device *cdev)
 		}
 		cdev->private->imask >>= 1;
 		cdev->private->iretry = 5;
+		i++;
 	}
+
 	return ret;
 }
 
@@ -76,7 +84,7 @@ ccw_device_sense_pgid_start(struct ccw_device *cdev)
 	cdev->private->state = DEV_STATE_SENSE_PGID;
 	cdev->private->imask = 0x80;
 	cdev->private->iretry = 5;
-	memset (&cdev->private->pgid, 0, sizeof (struct pgid));
+	memset (&cdev->private->pgid, 0, sizeof (cdev->private->pgid));
 	ret = __ccw_device_sense_pgid_start(cdev);
 	if (ret && ret != -EBUSY)
 		ccw_device_sense_pgid_done(cdev, ret);
@@ -91,6 +99,7 @@ __ccw_device_check_sense_pgid(struct ccw_device *cdev)
 {
 	struct subchannel *sch;
 	struct irb *irb;
+	int i;
 
 	sch = to_subchannel(cdev->dev.parent);
 	irb = &cdev->private->irb;
@@ -124,7 +133,8 @@ __ccw_device_check_sense_pgid(struct ccw_device *cdev)
 			      sch->schid.sch_no, sch->orb.lpm);
 		return -EACCES;
 	}
-	if (cdev->private->pgid.inf.ps.state2 == SNID_STATE2_RESVD_ELSE) {
+	i = 8 - ffs(cdev->private->imask);
+	if (cdev->private->pgid[i].inf.ps.state2 == SNID_STATE2_RESVD_ELSE) {
 		CIO_MSG_EVENT(2, "SNID - Device %04x on Subchannel 0.%x.%04x "
 			      "is reserved by someone else\n",
 			      cdev->private->devno, sch->schid.ssid,
@@ -162,12 +172,6 @@ ccw_device_sense_pgid_irq(struct ccw_device *cdev, enum dev_event dev_event)
 	memset(&cdev->private->irb, 0, sizeof(struct irb));
 	switch (ret) {
 	/* 0, -ETIME, -EOPNOTSUPP, -EAGAIN, -EACCES or -EUSERS */
-	case 0:			/* Sense Path Group ID successful. */
-		if (cdev->private->pgid.inf.ps.state1 == SNID_STATE1_RESET)
-			memcpy(&cdev->private->pgid, &css[0]->global_pgid,
-			       sizeof(struct pgid));
-		ccw_device_sense_pgid_done(cdev, 0);
-		break;
 	case -EOPNOTSUPP:	/* Sense Path Group ID not supported */
 		ccw_device_sense_pgid_done(cdev, -EOPNOTSUPP);
 		break;
@@ -176,13 +180,15 @@ ccw_device_sense_pgid_irq(struct ccw_device *cdev, enum dev_event dev_event)
 		break;
 	case -EACCES:		/* channel is not operational. */
 		sch->lpm &= ~cdev->private->imask;
+		/* Fall through. */
+	case 0:			/* Sense Path Group ID successful. */
 		cdev->private->imask >>= 1;
 		cdev->private->iretry = 5;
 		/* Fall through. */
 	case -EAGAIN:		/* Try again. */
 		ret = __ccw_device_sense_pgid_start(cdev);
 		if (ret != 0 && ret != -EBUSY)
-			ccw_device_sense_pgid_done(cdev, -ENODEV);
+			ccw_device_sense_pgid_done(cdev, ret);
 		break;
 	case -EUSERS:		/* device is reserved for someone else. */
 		ccw_device_sense_pgid_done(cdev, -EUSERS);
@@ -203,20 +209,20 @@ __ccw_device_do_pgid(struct ccw_device *cdev, __u8 func)
 	sch = to_subchannel(cdev->dev.parent);
 
 	/* Setup sense path group id channel program. */
-	cdev->private->pgid.inf.fc = func;
+	cdev->private->pgid[0].inf.fc = func;
 	ccw = cdev->private->iccws;
 	if (!cdev->private->flags.pgid_single) {
-		cdev->private->pgid.inf.fc |= SPID_FUNC_MULTI_PATH;
+		cdev->private->pgid[0].inf.fc |= SPID_FUNC_MULTI_PATH;
 		ccw->cmd_code = CCW_CMD_SUSPEND_RECONN;
 		ccw->cda = 0;
 		ccw->count = 0;
 		ccw->flags = CCW_FLAG_SLI | CCW_FLAG_CC;
 		ccw++;
 	} else
-		cdev->private->pgid.inf.fc |= SPID_FUNC_SINGLE_PATH;
+		cdev->private->pgid[0].inf.fc |= SPID_FUNC_SINGLE_PATH;
 
 	ccw->cmd_code = CCW_CMD_SET_PGID;
-	ccw->cda = (__u32) __pa (&cdev->private->pgid);
+	ccw->cda = (__u32) __pa (&cdev->private->pgid[0]);
 	ccw->count = sizeof (struct pgid);
 	ccw->flags = CCW_FLAG_SLI;
 
@@ -244,6 +250,48 @@ __ccw_device_do_pgid(struct ccw_device *cdev, __u8 func)
 }
 
 /*
+ * Helper function to send a nop ccw down a path.
+ */
+static int __ccw_device_do_nop(struct ccw_device *cdev)
+{
+	struct subchannel *sch;
+	struct ccw1 *ccw;
+	int ret;
+
+	sch = to_subchannel(cdev->dev.parent);
+
+	/* Setup nop channel program. */
+	ccw = cdev->private->iccws;
+	ccw->cmd_code = CCW_CMD_NOOP;
+	ccw->cda = 0;
+	ccw->count = 0;
+	ccw->flags = CCW_FLAG_SLI;
+
+	/* Reset device status. */
+	memset(&cdev->private->irb, 0, sizeof(struct irb));
+
+	/* Try multiple times. */
+	ret = -ENODEV;
+	if (cdev->private->iretry > 0) {
+		cdev->private->iretry--;
+		ret = cio_start (sch, cdev->private->iccws,
+				 cdev->private->imask);
+		/* ret is 0, -EBUSY, -EACCES or -ENODEV */
+		if ((ret != -EACCES) && (ret != -ENODEV))
+			return ret;
+	}
+	/* nop command failed on this path. Switch it off. */
+	sch->lpm &= ~cdev->private->imask;
+	sch->vpm &= ~cdev->private->imask;
+	CIO_MSG_EVENT(2, "NOP - Device %04x on Subchannel "
+		      "0.%x.%04x, lpm %02X, became 'not operational'\n",
+		      cdev->private->devno, sch->schid.ssid,
+		      sch->schid.sch_no, cdev->private->imask);
+	return ret;
+}
+
+
+/*
  * Called from interrupt context to check if a valid answer
  * to Set Path Group ID was received.
  */
@@ -282,6 +330,29 @@ __ccw_device_check_pgid(struct ccw_device *cdev)
 	return 0;
 }
 
+/*
+ * Called from interrupt context to check the path status after a nop has
+ * been send.
+ */
+static int __ccw_device_check_nop(struct ccw_device *cdev)
+{
+	struct subchannel *sch;
+	struct irb *irb;
+
+	sch = to_subchannel(cdev->dev.parent);
+	irb = &cdev->private->irb;
+	if (irb->scsw.fctl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC))
+		return -ETIME;
+	if (irb->scsw.cc == 3) {
+		CIO_MSG_EVENT(2, "NOP - Device %04x on Subchannel 0.%x.%04x,"
+			      " lpm %02X, became 'not operational'\n",
+			      cdev->private->devno, sch->schid.ssid,
+			      sch->schid.sch_no, cdev->private->imask);
+		return -EACCES;
+	}
+	return 0;
+}
+
 static void
 __ccw_device_verify_start(struct ccw_device *cdev)
 {
@@ -296,9 +367,12 @@ __ccw_device_verify_start(struct ccw_device *cdev)
 			if ((sch->vpm & imask) != (sch->lpm & imask))
 				break;
 		cdev->private->imask = imask;
-		func = (sch->vpm & imask) ?
-			SPID_FUNC_RESIGN : SPID_FUNC_ESTABLISH;
-		ret = __ccw_device_do_pgid(cdev, func);
+		if (cdev->private->options.pgroup) {
+			func = (sch->vpm & imask) ?
+				SPID_FUNC_RESIGN : SPID_FUNC_ESTABLISH;
+			ret = __ccw_device_do_pgid(cdev, func);
+		} else
+			ret = __ccw_device_do_nop(cdev);
 		if (ret == 0 || ret == -EBUSY)
 			return;
 		cdev->private->iretry = 5;
@@ -327,7 +401,10 @@ ccw_device_verify_irq(struct ccw_device *cdev, enum dev_event dev_event)
 	if (ccw_device_accumulate_and_sense(cdev, irb) != 0)
 		return;
 	sch = to_subchannel(cdev->dev.parent);
-	ret = __ccw_device_check_pgid(cdev);
+	if (cdev->private->options.pgroup)
+		ret = __ccw_device_check_pgid(cdev);
+	else
+		ret = __ccw_device_check_nop(cdev);
 	memset(&cdev->private->irb, 0, sizeof(struct irb));
 	switch (ret) {
 	/* 0, -ETIME, -EAGAIN, -EOPNOTSUPP or -EACCES */
@@ -345,11 +422,10 @@ ccw_device_verify_irq(struct ccw_device *cdev, enum dev_event dev_event)
 		 * One of those strange devices which claim to be able
 		 * to do multipathing but not for Set Path Group ID.
 		 */
-		if (cdev->private->flags.pgid_single) {
-			ccw_device_verify_done(cdev, -EOPNOTSUPP);
-			break;
-		}
-		cdev->private->flags.pgid_single = 1;
+		if (cdev->private->flags.pgid_single)
+			cdev->private->options.pgroup = 0;
+		else
+			cdev->private->flags.pgid_single = 1;
 		/* fall through. */
 	case -EAGAIN:		/* Try again. */
 		__ccw_device_verify_start(cdev);