8 files changed, 68 insertions, 24 deletions

diff --git a/arch/s390/include/asm/ccwdev.h b/arch/s390/include/asm/ccwdev.h
index 2a5419551176..f4bd346a52d3 100644
--- a/arch/s390/include/asm/ccwdev.h
+++ b/arch/s390/include/asm/ccwdev.h
@@ -142,6 +142,8 @@ struct ccw1;
 extern int ccw_device_set_options_mask(struct ccw_device *, unsigned long);
 extern int ccw_device_set_options(struct ccw_device *, unsigned long);
 extern void ccw_device_clear_options(struct ccw_device *, unsigned long);
+int ccw_device_is_pathgroup(struct ccw_device *cdev);
+int ccw_device_is_multipath(struct ccw_device *cdev);
 
 /* Allow for i/o completion notification after primary interrupt status. */
 #define CCWDEV_EARLY_NOTIFICATION       0x0001
@@ -151,6 +153,8 @@ extern void ccw_device_clear_options(struct ccw_device *, unsigned long);
 #define CCWDEV_DO_PATHGROUP             0x0004
 /* Allow forced onlining of boxed devices. */
 #define CCWDEV_ALLOW_FORCE              0x0008
+/* Try to use multipath mode. */
+#define CCWDEV_DO_MULTIPATH             0x0010
 
 extern int ccw_device_start(struct ccw_device *, struct ccw1 *,
                             unsigned long, __u8, unsigned long);
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index aaccc8ecfa8f..58ffbd1d04a1 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2208,13 +2208,6 @@ int dasd_generic_probe(struct ccw_device *cdev,
 {
         int ret;
 
-        ret = ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP);
-        if (ret) {
-                DBF_EVENT(DBF_WARNING,
-                       "dasd_generic_probe: could not set ccw-device options "
-                       "for %s\n", dev_name(&cdev->dev));
-                return ret;
-        }
         ret = dasd_add_sysfs_files(cdev);
         if (ret) {
                 DBF_EVENT(DBF_WARNING,
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 417b97cd3f94..a8ec0731609e 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -86,7 +86,8 @@ dasd_eckd_probe (struct ccw_device *cdev)
         int ret;
 
         /* set ECKD specific ccw-device options */
-        ret = ccw_device_set_options(cdev, CCWDEV_ALLOW_FORCE);
+        ret = ccw_device_set_options(cdev, CCWDEV_ALLOW_FORCE |
+                                     CCWDEV_DO_PATHGROUP | CCWDEV_DO_MULTIPATH);
         if (ret) {
                 DBF_EVENT(DBF_WARNING,
                        "dasd_eckd_probe: could not set ccw-device options "
@@ -1090,6 +1091,15 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
         struct dasd_block *block;
         int is_known, rc;
 
+        if (!ccw_device_is_pathgroup(device->cdev)) {
+                dev_warn(&device->cdev->dev,
+                         "A channel path group could not be established\n");
+                return -EIO;
+        }
+        if (!ccw_device_is_multipath(device->cdev)) {
+                dev_info(&device->cdev->dev,
+                         "The DASD is not operating in multipath mode\n");
+        }
         private = (struct dasd_eckd_private *) device->private;
         if (!private) {
                 private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA);
diff --git a/drivers/s390/char/tape_core.c b/drivers/s390/char/tape_core.c
index 5cd31e071647..27503a778fcb 100644
--- a/drivers/s390/char/tape_core.c
+++ b/drivers/s390/char/tape_core.c
@@ -579,7 +579,8 @@ tape_generic_probe(struct ccw_device *cdev)
         device = tape_alloc_device();
         if (IS_ERR(device))
                 return -ENODEV;
-        ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP);
+        ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP |
+                                     CCWDEV_DO_MULTIPATH);
         ret = sysfs_create_group(&cdev->dev.kobj, &tape_attr_group);
         if (ret) {
                 tape_put_device(device);
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index 349d8c52c0d0..d6e315dc0f98 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -601,7 +601,7 @@ ccw_device_offline(struct ccw_device *cdev)
         if (cdev->private->state != DEV_STATE_ONLINE)
                 return -EINVAL;
         /* Are we doing path grouping? */
-        if (!cdev->private->options.pgroup) {
+        if (!cdev->private->flags.pgroup) {
                 /* No, set state offline immediately. */
                 ccw_device_done(cdev, DEV_STATE_OFFLINE);
                 return 0;
diff --git a/drivers/s390/cio/device_ops.c b/drivers/s390/cio/device_ops.c
index 5ab90ec42318..d4be16acebe4 100644
--- a/drivers/s390/cio/device_ops.c
+++ b/drivers/s390/cio/device_ops.c
@@ -46,6 +46,7 @@ int ccw_device_set_options_mask(struct ccw_device *cdev, unsigned long flags)
         cdev->private->options.repall = (flags & CCWDEV_REPORT_ALL) != 0;
         cdev->private->options.pgroup = (flags & CCWDEV_DO_PATHGROUP) != 0;
         cdev->private->options.force = (flags & CCWDEV_ALLOW_FORCE) != 0;
+        cdev->private->options.mpath = (flags & CCWDEV_DO_MULTIPATH) != 0;
         return 0;
 }
 
@@ -74,6 +75,7 @@ int ccw_device_set_options(struct ccw_device *cdev, unsigned long flags)
         cdev->private->options.repall |= (flags & CCWDEV_REPORT_ALL) != 0;
         cdev->private->options.pgroup |= (flags & CCWDEV_DO_PATHGROUP) != 0;
         cdev->private->options.force |= (flags & CCWDEV_ALLOW_FORCE) != 0;
+        cdev->private->options.mpath |= (flags & CCWDEV_DO_MULTIPATH) != 0;
         return 0;
 }
 
@@ -90,9 +92,34 @@ void ccw_device_clear_options(struct ccw_device *cdev, unsigned long flags)
         cdev->private->options.repall &= (flags & CCWDEV_REPORT_ALL) == 0;
         cdev->private->options.pgroup &= (flags & CCWDEV_DO_PATHGROUP) == 0;
         cdev->private->options.force &= (flags & CCWDEV_ALLOW_FORCE) == 0;
+        cdev->private->options.mpath &= (flags & CCWDEV_DO_MULTIPATH) == 0;
 }
 
 /**
+ * ccw_device_is_pathgroup - determine if paths to this device are grouped
+ * @cdev: ccw device
+ *
+ * Return non-zero if there is a path group, zero otherwise.
+ */
+int ccw_device_is_pathgroup(struct ccw_device *cdev)
+{
+        return cdev->private->flags.pgroup;
+}
+EXPORT_SYMBOL(ccw_device_is_pathgroup);
+
+/**
+ * ccw_device_is_multipath - determine if device is operating in multipath mode
+ * @cdev: ccw device
+ *
+ * Return non-zero if device is operating in multipath mode, zero otherwise.
+ */
+int ccw_device_is_multipath(struct ccw_device *cdev)
+{
+        return cdev->private->flags.mpath;
+}
+EXPORT_SYMBOL(ccw_device_is_multipath);
+
+/**
  * ccw_device_clear() - terminate I/O request processing
  * @cdev: target ccw device
  * @intparm: interruption parameter; value is only used if no I/O is
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);
diff --git a/drivers/s390/cio/io_sch.h b/drivers/s390/cio/io_sch.h
index 8942dc092d0a..b387c80d1888 100644
--- a/drivers/s390/cio/io_sch.h
+++ b/drivers/s390/cio/io_sch.h
@@ -156,9 +156,9 @@ struct ccw_device_private {
                 unsigned int repall:1;  /* report every interrupt status */
                 unsigned int pgroup:1;  /* do path grouping */
                 unsigned int force:1;   /* allow forced online */
+                unsigned int mpath:1;   /* do multipathing */
         } __attribute__ ((packed)) options;
         struct {
-                unsigned int pgid_single:1; /* use single path for Set PGID */
                 unsigned int esid:1;        /* Ext. SenseID supported by HW */
                 unsigned int dosense:1;     /* delayed SENSE required */
                 unsigned int doverify:1;    /* delayed path verification */
@@ -167,6 +167,8 @@ struct ccw_device_private {
                 unsigned int fake_irb:1;    /* deliver faked irb */
                 unsigned int resuming:1;    /* recognition while resume */
                 unsigned int pgid_rdy:1;    /* pgids are ready */
+                unsigned int pgroup:1;      /* pathgroup is set up */
+                unsigned int mpath:1;       /* multipathing is set up */
         } __attribute__((packed)) flags;
         unsigned long intparm;  /* user interruption parameter */
         struct qdio_irq *qdio_data;