[S390] cio: Rework css driver.

Rework the css driver methods to provide sane callbacks for
subchannels of all types.

As a bonus, this cleans up and simplyfies the machine check
handling for I/O subchannels a lot.

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

1 files changed, 16 insertions, 107 deletions

diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 53e7496dc90c..020566571e07 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -283,7 +283,7 @@ static int css_register_subchannel(struct subchannel *sch)
         return ret;
 }
 
-static int css_probe_device(struct subchannel_id schid)
+int css_probe_device(struct subchannel_id schid)
 {
         int ret;
         struct subchannel *sch;
@@ -330,112 +330,6 @@ int css_sch_is_valid(struct schib *schib)
 }
 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 
-static int css_get_subchannel_status(struct subchannel *sch)
-{
-        struct schib schib;
-
-        if (stsch(sch->schid, &schib))
-                return CIO_GONE;
-        if (!css_sch_is_valid(&schib))
-                return CIO_GONE;
-        if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
-                return CIO_REVALIDATE;
-        if (!sch->lpm)
-                return CIO_NO_PATH;
-        return CIO_OPER;
-}
-
-static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
-{
-        int event, ret, disc;
-        unsigned long flags;
-        enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action;
-
-        spin_lock_irqsave(sch->lock, flags);
-        disc = device_is_disconnected(sch);
-        if (disc && slow) {
-                /* Disconnected devices are evaluated directly only.*/
-                spin_unlock_irqrestore(sch->lock, flags);
-                return 0;
-        }
-        /* No interrupt after machine check - kill pending timers. */
-        device_kill_pending_timer(sch);
-        if (!disc && !slow) {
-                /* Non-disconnected devices are evaluated on the slow path. */
-                spin_unlock_irqrestore(sch->lock, flags);
-                return -EAGAIN;
-        }
-        event = css_get_subchannel_status(sch);
-        CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
-                      sch->schid.ssid, sch->schid.sch_no, event,
-                      disc ? "disconnected" : "normal",
-                      slow ? "slow" : "fast");
-        /* Analyze subchannel status. */
-        action = NONE;
-        switch (event) {
-        case CIO_NO_PATH:
-                if (disc) {
-                        /* Check if paths have become available. */
-                        action = REPROBE;
-                        break;
-                }
-                /* fall through */
-        case CIO_GONE:
-                /* Prevent unwanted effects when opening lock. */
-                cio_disable_subchannel(sch);
-                device_set_disconnected(sch);
-                /* Ask driver what to do with device. */
-                action = UNREGISTER;
-                if (sch->driver && sch->driver->notify) {
-                        spin_unlock_irqrestore(sch->lock, flags);
-                        ret = sch->driver->notify(sch, event);
-                        spin_lock_irqsave(sch->lock, flags);
-                        if (ret)
-                                action = NONE;
-                }
-                break;
-        case CIO_REVALIDATE:
-                /* Device will be removed, so no notify necessary. */
-                if (disc)
-                        /* Reprobe because immediate unregister might block. */
-                        action = REPROBE;
-                else
-                        action = UNREGISTER_PROBE;
-                break;
-        case CIO_OPER:
-                if (disc)
-                        /* Get device operational again. */
-                        action = REPROBE;
-                break;
-        }
-        /* Perform action. */
-        ret = 0;
-        switch (action) {
-        case UNREGISTER:
-        case UNREGISTER_PROBE:
-                /* Unregister device (will use subchannel lock). */
-                spin_unlock_irqrestore(sch->lock, flags);
-                css_sch_device_unregister(sch);
-                spin_lock_irqsave(sch->lock, flags);
-
-                /* Reset intparm to zeroes. */
-                sch->schib.pmcw.intparm = 0;
-                cio_modify(sch);
-                break;
-        case REPROBE:
-                device_trigger_reprobe(sch);
-                break;
-        default:
-                break;
-        }
-        spin_unlock_irqrestore(sch->lock, flags);
-        /* Probe if necessary. */
-        if (action == UNREGISTER_PROBE)
-                ret = css_probe_device(sch->schid);
-
-        return ret;
-}
-
 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 {
         struct schib schib;
@@ -454,6 +348,21 @@ static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
         return css_probe_device(schid);
 }
 
+static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
+{
+        int ret = 0;
+
+        if (sch->driver) {
+                if (sch->driver->sch_event)
+                        ret = sch->driver->sch_event(sch, slow);
+                else
+                        dev_dbg(&sch->dev,
+                                "Got subchannel machine check but "
+                                "no sch_event handler provided.\n");
+        }
+        return ret;
+}
+
 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 {
         struct subchannel *sch;