[S390] cio: introduce cio_commit_config

To change the configuration of a subchannel we alter the modifiable
bits of the subchannel's schib field and issue a modify subchannel.
There can be the case that not all changes were applied -or worse-
quietly overwritten by the hardware. With the next store subchannel
we obtain the current state of the hardware but lose our target
configuration.

With this patch we introduce a subchannel_config structure which
contains the target subchannel configuration. Additionally the msch
wrapper cio_modify is replaced with cio_commit_config which
copies the desired changes to a temporary schib. msch is then
called with the temporary schib. This schib is only written back
to the subchannel if all changes were applied.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 76bbb1e74c29..1b2d5149de5a 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -128,8 +128,8 @@ css_free_subchannel(struct subchannel *sch)
 {
         if (sch) {
                 /* Reset intparm to zeroes. */
-                sch->schib.pmcw.intparm = 0;
-                cio_modify(sch);
+                sch->config.intparm = 0;
+                cio_commit_config(sch);
                 kfree(sch->lock);
                 kfree(sch);
         }