s390/cio: fix pgid reserved check

The check to whom a device is reserved is done by checking the path
state of the affected channel paths. If it turns out that one path is
flagged as reserved by someone else the whole device is marked as such.

However the meaning of the RESVD_ELSE bit is that the addressed device
is reserved to a different pathgroup (and not reserved to a different
LPAR). If we do this test on a path which is currently not a member of
the pathgroup we could erroneously mark the device as reserved to
someone else.

To fix this collect the reserved state for all potential members of the
pathgroup and only mark the device as reserved if all of those potential
members have the RESVD_ELSE bit set.

Cc: stable@vger.kernel.org
Acked-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/device_pgid.c

@@ -234,7 +234,7 @@ static int pgid_cmp(struct pgid *p1, struct pgid *p2)
  * Determine pathgroup state from PGID data.
  */
 static void pgid_analyze(struct ccw_device *cdev, struct pgid **p,
-			 int *mismatch, int *reserved, u8 *reset)
+			 int *mismatch, u8 *reserved, u8 *reset)
 {
 	struct pgid *pgid = &cdev->private->pgid[0];
 	struct pgid *first = NULL;
@@ -248,7 +248,7 @@ static void pgid_analyze(struct ccw_device *cdev, struct pgid **p,
 		if ((cdev->private->pgid_valid_mask & lpm) == 0)
 			continue;
 		if (pgid->inf.ps.state2 == SNID_STATE2_RESVD_ELSE)
-			*reserved = 1;
+			*reserved |= lpm;
 		if (pgid_is_reset(pgid)) {
 			*reset |= lpm;
 			continue;
@@ -316,14 +316,14 @@ static void snid_done(struct ccw_device *cdev, int rc)
 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
 	struct pgid *pgid;
 	int mismatch = 0;
-	int reserved = 0;
+	u8 reserved = 0;
 	u8 reset = 0;
 	u8 donepm;
 
 	if (rc)
 		goto out;
 	pgid_analyze(cdev, &pgid, &mismatch, &reserved, &reset);
-	if (reserved)
+	if (reserved == cdev->private->pgid_valid_mask)
 		rc = -EUSERS;
 	else if (mismatch)
 		rc = -EOPNOTSUPP;
@@ -336,7 +336,7 @@ static void snid_done(struct ccw_device *cdev, int rc)
 	}
 out:
 	CIO_MSG_EVENT(2, "snid: device 0.%x.%04x: rc=%d pvm=%02x vpm=%02x "
-		      "todo=%02x mism=%d rsvd=%d reset=%02x\n", id->ssid,
+		      "todo=%02x mism=%d rsvd=%02x reset=%02x\n", id->ssid,
 		      id->devno, rc, cdev->private->pgid_valid_mask, sch->vpm,
 		      cdev->private->pgid_todo_mask, mismatch, reserved, reset);
 	switch (rc) {