[S390] cio: Make isc handling more robust.

Introduce an ->isc field in the subchannel to store the desired
interruption subclass, since sch->schib.pmcw.isc may be overwritten
by the hardware on stsch() after machine checks.

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

4 files changed, 10 insertions, 14 deletions

diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index 23ffcc4768a7..08a578161306 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -407,8 +407,7 @@ cio_modify (struct subchannel *sch)
 /*
  * Enable subchannel.
  */
-int cio_enable_subchannel(struct subchannel *sch, unsigned int isc,
-                          u32 intparm)
+int cio_enable_subchannel(struct subchannel *sch, u32 intparm)
 {
         char dbf_txt[15];
         int ccode;
@@ -426,7 +425,7 @@ int cio_enable_subchannel(struct subchannel *sch, unsigned int isc,
 
         for (retry = 5, ret = 0; retry > 0; retry--) {
                 sch->schib.pmcw.ena = 1;
-                sch->schib.pmcw.isc = isc;
+                sch->schib.pmcw.isc = sch->isc;
                 sch->schib.pmcw.intparm = intparm;
                 ret = cio_modify(sch);
                 if (ret == -ENODEV)
@@ -600,6 +599,7 @@ cio_validate_subchannel (struct subchannel *sch, struct subchannel_id schid)
         else
                 sch->opm = chp_get_sch_opm(sch);
         sch->lpm = sch->schib.pmcw.pam & sch->opm;
+        sch->isc = 3;
 
         CIO_DEBUG(KERN_INFO, 0,
                   "Detected device %04x on subchannel 0.%x.%04X"
@@ -610,13 +610,11 @@ cio_validate_subchannel (struct subchannel *sch, struct subchannel_id schid)
 
         /*
          * We now have to initially ...
-         *  ... set "interruption subclass"
          *  ... enable "concurrent sense"
          *  ... enable "multipath mode" if more than one
          *        CHPID is available. This is done regardless
          *        whether multiple paths are available for us.
          */
-        sch->schib.pmcw.isc = 3;        /* could be smth. else */
         sch->schib.pmcw.csense = 1;     /* concurrent sense */
         sch->schib.pmcw.ena = 0;
         if ((sch->lpm & (sch->lpm - 1)) != 0)
@@ -812,6 +810,7 @@ cio_probe_console(void)
          * enable console I/O-interrupt subclass 7
          */
         ctl_set_bit(6, 24);
+        console_subchannel.isc = 7;
         console_subchannel.schib.pmcw.isc = 7;
         console_subchannel.schib.pmcw.intparm =
                 (u32)(addr_t)&console_subchannel;
diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h
index 08f2235c5a6f..3c75412904dc 100644
--- a/drivers/s390/cio/cio.h
+++ b/drivers/s390/cio/cio.h
@@ -74,6 +74,7 @@ struct subchannel {
         __u8 lpm;               /* logical path mask */
         __u8 opm;               /* operational path mask */
         struct schib schib;     /* subchannel information block */
+        int isc; /* desired interruption subclass */
         struct chsc_ssd_info ssd_info;  /* subchannel description */
         struct device dev;      /* entry in device tree */
         struct css_driver *driver;
@@ -85,7 +86,7 @@ struct subchannel {
 #define to_subchannel(n) container_of(n, struct subchannel, dev)
 
 extern int cio_validate_subchannel (struct subchannel *, struct subchannel_id);
-extern int cio_enable_subchannel(struct subchannel *, unsigned int, u32);
+extern int cio_enable_subchannel(struct subchannel *, u32);
 extern int cio_disable_subchannel (struct subchannel *);
 extern int cio_cancel (struct subchannel *);
 extern int cio_clear (struct subchannel *);
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index 4b92c84fb438..99403b0a97a7 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -555,8 +555,7 @@ ccw_device_recognition(struct ccw_device *cdev)
             (cdev->private->state != DEV_STATE_BOXED))
                 return -EINVAL;
         sch = to_subchannel(cdev->dev.parent);
-        ret = cio_enable_subchannel(sch, sch->schib.pmcw.isc,
-                                    (u32)(addr_t)sch);
+        ret = cio_enable_subchannel(sch, (u32)(addr_t)sch);
         if (ret != 0)
                 /* Couldn't enable the subchannel for i/o. Sick device. */
                 return ret;
@@ -667,8 +666,7 @@ ccw_device_online(struct ccw_device *cdev)
         sch = to_subchannel(cdev->dev.parent);
         if (css_init_done && !get_device(&cdev->dev))
                 return -ENODEV;
-        ret = cio_enable_subchannel(sch, sch->schib.pmcw.isc,
-                                    (u32)(addr_t)sch);
+        ret = cio_enable_subchannel(sch, (u32)(addr_t)sch);
         if (ret != 0) {
                 /* Couldn't enable the subchannel for i/o. Sick device. */
                 if (ret == -ENODEV)
@@ -1048,8 +1046,7 @@ ccw_device_start_id(struct ccw_device *cdev, enum dev_event dev_event)
         struct subchannel *sch;
 
         sch = to_subchannel(cdev->dev.parent);
-        if (cio_enable_subchannel(sch, sch->schib.pmcw.isc,
-                                  (u32)(addr_t)sch) != 0)
+        if (cio_enable_subchannel(sch, (u32)(addr_t)sch) != 0)
                 /* Couldn't enable the subchannel for i/o. Sick device. */
                 return;
 
@@ -1082,7 +1079,6 @@ device_trigger_reprobe(struct subchannel *sch)
          */
         sch->lpm = sch->schib.pmcw.pam & sch->opm;
         /* Re-set some bits in the pmcw that were lost. */
-        sch->schib.pmcw.isc = 3;
         sch->schib.pmcw.csense = 1;
         sch->schib.pmcw.ena = 0;
         if ((sch->lpm & (sch->lpm - 1)) != 0)
diff --git a/drivers/s390/cio/device_ops.c b/drivers/s390/cio/device_ops.c
index a1718a0aa539..f308ad55a6d5 100644
--- a/drivers/s390/cio/device_ops.c
+++ b/drivers/s390/cio/device_ops.c
@@ -508,7 +508,7 @@ ccw_device_stlck(struct ccw_device *cdev)
                 return -ENOMEM;
         }
         spin_lock_irqsave(sch->lock, flags);
-        ret = cio_enable_subchannel(sch, 3, (u32)(addr_t)sch);
+        ret = cio_enable_subchannel(sch, (u32)(addr_t)sch);
         if (ret)
                 goto out_unlock;
         /*