[S390] cio: fix subchannel channel-path data usage

Ensure that channel-path related subchannel data is only retrieved and
used when it is valid and that it is updated when it may have changed.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 48 insertions, 5 deletions

diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index fcc641e578f4..27c6d9e55b23 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -21,6 +21,7 @@
 #include "chsc.h"
 #include "device.h"
 #include "idset.h"
+#include "chp.h"
 
 int css_init_done = 0;
 static int need_reprobe = 0;
@@ -125,8 +126,52 @@ void css_sch_device_unregister(struct subchannel *sch)
         mutex_unlock(&sch->reg_mutex);
 }
 
-static int
-css_register_subchannel(struct subchannel *sch)
+static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
+{
+        int i;
+        int mask;
+
+        memset(ssd, 0, sizeof(struct chsc_ssd_info));
+        ssd->path_mask = pmcw->pim;
+        for (i = 0; i < 8; i++) {
+                mask = 0x80 >> i;
+                if (pmcw->pim & mask) {
+                        chp_id_init(&ssd->chpid[i]);
+                        ssd->chpid[i].id = pmcw->chpid[i];
+                }
+        }
+}
+
+static void ssd_register_chpids(struct chsc_ssd_info *ssd)
+{
+        int i;
+        int mask;
+
+        for (i = 0; i < 8; i++) {
+                mask = 0x80 >> i;
+                if (ssd->path_mask & mask)
+                        if (!chp_is_registered(ssd->chpid[i]))
+                                chp_new(ssd->chpid[i]);
+        }
+}
+
+void css_update_ssd_info(struct subchannel *sch)
+{
+        int ret;
+
+        if (cio_is_console(sch->schid)) {
+                /* Console is initialized too early for functions requiring
+                 * memory allocation. */
+                ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
+        } else {
+                ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
+                if (ret)
+                        ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
+                ssd_register_chpids(&sch->ssd_info);
+        }
+}
+
+static int css_register_subchannel(struct subchannel *sch)
 {
         int ret;
 
@@ -135,9 +180,7 @@ css_register_subchannel(struct subchannel *sch)
         sch->dev.bus = &css_bus_type;
         sch->dev.release = &css_subchannel_release;
         sch->dev.groups = subch_attr_groups;
-
-        css_get_ssd_info(sch);
-
+        css_update_ssd_info(sch);
         /* make it known to the system */
         ret = css_sch_device_register(sch);
         if (ret) {