[S390] cio: split PGID settings and status

Split setting (driver wants feature enabled) and status (feature
setup was successful) for PGID related ccw device features so that
setup errors can be detected. Previously, incorrectly handled setup
errors could in rare cases lead to erratic I/O behavior and
permanently unusuable devices.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 20 insertions, 13 deletions

diff --git a/drivers/s390/cio/device_pgid.c b/drivers/s390/cio/device_pgid.c
index ce493144b054..3323042ba755 100644
--- a/drivers/s390/cio/device_pgid.c
+++ b/drivers/s390/cio/device_pgid.c
@@ -30,8 +30,8 @@ static void verify_done(struct ccw_device *cdev, int rc)
 {
         struct subchannel *sch = to_subchannel(cdev->dev.parent);
         struct ccw_dev_id *id = &cdev->private->dev_id;
-        int mpath = !cdev->private->flags.pgid_single;
-        int pgroup = cdev->private->options.pgroup;
+        int mpath = cdev->private->flags.mpath;
+        int pgroup = cdev->private->flags.pgroup;
 
         if (rc)
                 goto out;
@@ -150,7 +150,7 @@ static void spid_do(struct ccw_device *cdev)
                 fn = SPID_FUNC_ESTABLISH;
         else
                 fn = SPID_FUNC_RESIGN;
-        if (!cdev->private->flags.pgid_single)
+        if (cdev->private->flags.mpath)
                 fn |= SPID_FUNC_MULTI_PATH;
         spid_build_cp(cdev, fn);
         ccw_request_start(cdev);
@@ -177,13 +177,13 @@ static void spid_callback(struct ccw_device *cdev, void *data, int rc)
         case -EACCES:
                 break;
         case -EOPNOTSUPP:
-                if (!cdev->private->flags.pgid_single) {
+                if (cdev->private->flags.mpath) {
                         /* Try without multipathing. */
-                        cdev->private->flags.pgid_single = 1;
+                        cdev->private->flags.mpath = 0;
                         goto out_restart;
                 }
                 /* Try without pathgrouping. */
-                cdev->private->options.pgroup = 0;
+                cdev->private->flags.pgroup = 0;
                 goto out_restart;
         default:
                 goto err;
@@ -374,7 +374,7 @@ static void verify_start(struct ccw_device *cdev)
         req->timeout    = PGID_TIMEOUT;
         req->maxretries = PGID_RETRIES;
         req->lpm        = 0x80;
-        if (cdev->private->options.pgroup) {
+        if (cdev->private->flags.pgroup) {
                 req->callback   = spid_callback;
                 spid_do(cdev);
         } else {
@@ -400,10 +400,17 @@ void ccw_device_verify_start(struct ccw_device *cdev)
         CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
         if (!cdev->private->flags.pgid_rdy) {
                 /* No pathgrouping possible. */
-                cdev->private->options.pgroup = 0;
-                cdev->private->flags.pgid_single = 1;
-        } else
-                cdev->private->flags.pgid_single = 0;
+                cdev->private->flags.pgroup = 0;
+                cdev->private->flags.mpath = 0;
+        } else {
+                /*
+                 * Initialize pathgroup and multipath state with target values.
+                 * They may change in the course of path verification.
+                 */
+                cdev->private->flags.pgroup = cdev->private->options.pgroup;
+                cdev->private->flags.mpath = cdev->private->options.mpath;
+
+        }
         cdev->private->flags.doverify = 0;
         verify_start(cdev);
 }
@@ -419,7 +426,7 @@ static void disband_callback(struct ccw_device *cdev, void *data, int rc)
         if (rc)
                 goto out;
         /* Ensure consistent multipathing state at device and channel. */
-        cdev->private->flags.pgid_single = 1;
+        cdev->private->flags.mpath = 0;
         if (sch->config.mp) {
                 sch->config.mp = 0;
                 rc = cio_commit_config(sch);
@@ -453,7 +460,7 @@ void ccw_device_disband_start(struct ccw_device *cdev)
         req->lpm        = sch->schib.pmcw.pam & sch->opm;
         req->callback   = disband_callback;
         fn = SPID_FUNC_DISBAND;
-        if (!cdev->private->flags.pgid_single)
+        if (cdev->private->flags.mpath)
                 fn |= SPID_FUNC_MULTI_PATH;
         spid_build_cp(cdev, fn);
         ccw_request_start(cdev);