s390/cio: handle unknown pgroup state

When an attempt to query or modify the grouping state of a channel path
fails due to a timeout, we cannot be sure about its state. To get back to
a defined state, disband the whole path group and try again while excluding
the offending path.

Reviewed-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>

1 files changed, 61 insertions, 3 deletions

diff --git a/drivers/s390/cio/device_pgid.c b/drivers/s390/cio/device_pgid.c
index f12beb72f263..37ada05e82a5 100644
--- a/drivers/s390/cio/device_pgid.c
+++ b/drivers/s390/cio/device_pgid.c
@@ -23,6 +23,8 @@
 #define PGID_RETRIES    256
 #define PGID_TIMEOUT    (10 * HZ)
 
+static void verify_start(struct ccw_device *cdev);
+
 /*
  * Process path verification data and report result.
  */
@@ -142,6 +144,48 @@ static void spid_build_cp(struct ccw_device *cdev, u8 fn)
         req->cp         = cp;
 }
 
+static void pgid_wipeout_callback(struct ccw_device *cdev, void *data, int rc)
+{
+        if (rc) {
+                /* We don't know the path groups' state. Abort. */
+                verify_done(cdev, rc);
+                return;
+        }
+        /*
+         * Path groups have been reset. Restart path verification but
+         * leave paths in path_noirq_mask out.
+         */
+        cdev->private->flags.pgid_unknown = 0;
+        verify_start(cdev);
+}
+
+/*
+ * Reset pathgroups and restart path verification, leave unusable paths out.
+ */
+static void pgid_wipeout_start(struct ccw_device *cdev)
+{
+        struct subchannel *sch = to_subchannel(cdev->dev.parent);
+        struct ccw_dev_id *id = &cdev->private->dev_id;
+        struct ccw_request *req = &cdev->private->req;
+        u8 fn;
+
+        CIO_MSG_EVENT(2, "wipe: device 0.%x.%04x: pvm=%02x nim=%02x\n",
+                      id->ssid, id->devno, cdev->private->pgid_valid_mask,
+                      cdev->private->path_noirq_mask);
+
+        /* Initialize request data. */
+        memset(req, 0, sizeof(*req));
+        req->timeout    = PGID_TIMEOUT;
+        req->maxretries = PGID_RETRIES;
+        req->lpm        = sch->schib.pmcw.pam;
+        req->callback   = pgid_wipeout_callback;
+        fn = SPID_FUNC_DISBAND;
+        if (cdev->private->flags.mpath)
+                fn |= SPID_FUNC_MULTI_PATH;
+        spid_build_cp(cdev, fn);
+        ccw_request_start(cdev);
+}
+
 /*
  * Perform establish/resign SET PGID on a single path.
  */
@@ -167,11 +211,14 @@ static void spid_do(struct ccw_device *cdev)
         return;
 
 out_nopath:
+        if (cdev->private->flags.pgid_unknown) {
+                /* At least one SPID could be partially done. */
+                pgid_wipeout_start(cdev);
+                return;
+        }
         verify_done(cdev, sch->vpm ? 0 : -EACCES);
 }
 
-static void verify_start(struct ccw_device *cdev);
-
 /*
  * Process SET PGID request result for a single path.
  */
@@ -357,6 +404,10 @@ out:
                       cdev->private->pgid_todo_mask, mismatch, reserved, reset);
         switch (rc) {
         case 0:
+                if (cdev->private->flags.pgid_unknown) {
+                        pgid_wipeout_start(cdev);
+                        return;
+                }
                 /* Anything left to do? */
                 if (cdev->private->pgid_todo_mask == 0) {
                         verify_done(cdev, sch->vpm == 0 ? -EACCES : 0);
@@ -400,6 +451,7 @@ static void snid_do(struct ccw_device *cdev)
 {
         struct subchannel *sch = to_subchannel(cdev->dev.parent);
         struct ccw_request *req = &cdev->private->req;
+        int ret;
 
         req->lpm = lpm_adjust(req->lpm, sch->schib.pmcw.pam &
                               ~cdev->private->path_noirq_mask);
@@ -410,7 +462,13 @@ static void snid_do(struct ccw_device *cdev)
         return;
 
 out_nopath:
-        snid_done(cdev, cdev->private->pgid_valid_mask ? 0 : -EACCES);
+        if (cdev->private->pgid_valid_mask)
+                ret = 0;
+        else if (cdev->private->path_noirq_mask)
+                ret = -ETIME;
+        else
+                ret = -EACCES;
+        snid_done(cdev, ret);
 }
 
 /*