[PATCH] s390: fix I/O termination race in cio

Fix a race condition in the I/O termination logic.  The race can cause I/O to
a dasd device to fail with no retry left after turning one channel path to the
device off and on multiple times.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 22 deletions

diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index 6412b2c3edd3..daedb00a4346 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -242,28 +242,10 @@ s390_subchannel_remove_chpid(struct device *dev, void *data)
         if (sch->vpm == mask)
                 goto out_unreg;
 
-        if ((sch->schib.scsw.actl & (SCSW_ACTL_CLEAR_PEND |
-                                     SCSW_ACTL_HALT_PEND |
-                                     SCSW_ACTL_START_PEND |
-                                     SCSW_ACTL_RESUME_PEND)) &&
-            (sch->schib.pmcw.lpum == mask)) {
-                int cc = cio_cancel(sch);
-                
-                if (cc == -ENODEV)
-                        goto out_unreg;
-
-                if (cc == -EINVAL) {
-                        cc = cio_clear(sch);
-                        if (cc == -ENODEV)
-                                goto out_unreg;
-                        /* Call handler. */
-                        if (sch->driver && sch->driver->termination)
-                                sch->driver->termination(&sch->dev);
-                        goto out_unlock;
-                }
-        } else if ((sch->schib.scsw.actl & SCSW_ACTL_DEVACT) &&
-                   (sch->schib.scsw.actl & SCSW_ACTL_SCHACT) &&
-                   (sch->schib.pmcw.lpum == mask)) {
+        if ((sch->schib.scsw.actl & SCSW_ACTL_DEVACT) &&
+            (sch->schib.scsw.actl & SCSW_ACTL_SCHACT) &&
+            (sch->schib.pmcw.lpum == mask) &&
+            (sch->vpm == 0)) {
                 int cc;
 
                 cc = cio_clear(sch);