[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>
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index e1a3786..9e24967 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -1026,11 +1026,12 @@
* we have before performing device selection :/
*/
sch->lpm = sch->schib.pmcw.pam & sch->opm;
- /* Re-set some bits in the pmcw that were lost. */
- sch->schib.pmcw.csense = 1;
- sch->schib.pmcw.ena = 0;
- if ((sch->lpm & (sch->lpm - 1)) != 0)
- sch->schib.pmcw.mp = 1;
+ /*
+ * Use the initial configuration since we can't be shure that the old
+ * paths are valid.
+ */
+ io_subchannel_init_config(sch);
+
/* We should also udate ssd info, but this has to wait. */
/* Check if this is another device which appeared on the same sch. */
if (sch->schib.pmcw.dev != cdev->private->dev_id.devno) {