[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, 15 insertions, 1 deletions

diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h
index fb125efd6891..5150fba742ac 100644
--- a/drivers/s390/cio/cio.h
+++ b/drivers/s390/cio/cio.h
@@ -45,6 +45,19 @@ struct pmcw {
                                 /*  ... in an operand exception.       */
 } __attribute__ ((packed));
 
+/* Target SCHIB configuration. */
+struct schib_config {
+        u64 mba;
+        u32 intparm;
+        u16 mbi;
+        u32 isc:3;
+        u32 ena:1;
+        u32 mme:2;
+        u32 mp:1;
+        u32 csense:1;
+        u32 mbfc:1;
+} __attribute__ ((packed));
+
 /*
  * subchannel information block
  */
@@ -83,6 +96,7 @@ struct subchannel {
         struct css_driver *driver;
         void *private; /* private per subchannel type data */
         struct work_struct work;
+        struct schib_config config;
 } __attribute__ ((aligned(8)));
 
 #define IO_INTERRUPT_TYPE          0 /* I/O interrupt type */
@@ -101,8 +115,8 @@ extern int cio_start_key (struct subchannel *, struct ccw1 *, __u8, __u8);
 extern int cio_cancel (struct subchannel *);
 extern int cio_set_options (struct subchannel *, int);
 extern int cio_get_options (struct subchannel *);
-extern int cio_modify (struct subchannel *);
 extern int cio_update_schib(struct subchannel *sch);
+extern int cio_commit_config(struct subchannel *sch);
 
 int cio_tm_start_key(struct subchannel *sch, struct tcw *tcw, u8 lpm, u8 key);
 int cio_tm_intrg(struct subchannel *sch);