s390x: refactor error handling for CSCH handler

Simplify the error handling of the CSCH.  Let the code detecting the
condition tell (in a less ambiguous way) how it's to be handled. No
changes in behavior.
Signed-off-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Message-Id: <20171017140453.51099-6-pasic@linux.vnet.ibm.com>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Reviewed-by: NDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cohuck@redhat.com>

hw/s390x/css.c

@@ -1435,26 +1435,20 @@ IOInstEnding css_do_xsch(SubchDev *sch)
     return IOINST_CC_EXPECTED;
 }
 
-int css_do_csch(SubchDev *sch)
+IOInstEnding css_do_csch(SubchDev *sch)
 {
     SCSW *s = &sch->curr_status.scsw;
     PMCW *p = &sch->curr_status.pmcw;
-    int ret;
 
     if (~(p->flags) & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA)) {
-        ret = -ENODEV;
-        goto out;
+        return IOINST_CC_NOT_OPERATIONAL;
     }
 
     /* Trigger the clear function. */
     s->ctrl &= ~(SCSW_CTRL_MASK_FCTL | SCSW_CTRL_MASK_ACTL);
     s->ctrl |= SCSW_FCTL_CLEAR_FUNC | SCSW_ACTL_CLEAR_PEND;
 
-    do_subchannel_work(sch);
-    ret = 0;
-
-out:
-    return ret;
+    return do_subchannel_work(sch);
 }
 
 int css_do_hsch(SubchDev *sch)

include/hw/s390x/css.h

@@ -241,7 +241,7 @@ int css_do_stsch(SubchDev *sch, SCHIB *schib);
 bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid);
 int css_do_msch(SubchDev *sch, const SCHIB *schib);
 IOInstEnding css_do_xsch(SubchDev *sch);
-int css_do_csch(SubchDev *sch);
+IOInstEnding css_do_csch(SubchDev *sch);
 int css_do_hsch(SubchDev *sch);
 IOInstEnding css_do_ssch(SubchDev *sch, ORB *orb);
 int css_do_tsch_get_irb(SubchDev *sch, IRB *irb, int *irb_len);

target/s390x/ioinst.c

@@ -60,8 +60,6 @@ void ioinst_handle_csch(S390CPU *cpu, uint64_t reg1)
 {
     int cssid, ssid, schid, m;
     SubchDev *sch;
-    int ret = -ENODEV;
-    int cc;
 
     if (ioinst_disassemble_sch_ident(reg1, &m, &cssid, &ssid, &schid)) {
         program_interrupt(&cpu->env, PGM_OPERAND, 4);
@@ -69,15 +67,11 @@ void ioinst_handle_csch(S390CPU *cpu, uint64_t reg1)
     }
     trace_ioinst_sch_id("csch", cssid, ssid, schid);
     sch = css_find_subch(m, cssid, ssid, schid);
-    if (sch && css_subch_visible(sch)) {
-        ret = css_do_csch(sch);
-    }
-    if (ret == -ENODEV) {
-        cc = 3;
-    } else {
-        cc = 0;
+    if (!sch || !css_subch_visible(sch)) {
+        setcc(cpu, 3);
+        return;
     }
-    setcc(cpu, cc);
+    setcc(cpu, css_do_csch(sch));
 }
 
 void ioinst_handle_hsch(S390CPU *cpu, uint64_t reg1)