[S390] dasd: add ifcc handling

Adding interface control check (ifcc) handling in error recovery.
First retry up to 255 times and if all retries fail try an alternate
path if possible.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 52 insertions, 27 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index d640427c74c8..ab4f64c49829 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1057,12 +1057,11 @@ void dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
                 if (device->features & DASD_FEATURE_ERPLOG) {
                         dasd_log_sense(cqr, irb);
                 }
-                /* If we have no sense data, or we just don't want complex ERP
-                 * for this request, but if we have retries left, then just
-                 * reset this request and retry it in the fastpath
+                /*
+                 * If we don't want complex ERP for this request, then just
+                 * reset this and retry it in the fastpath
                  */
-                if (!(cqr->irb.esw.esw0.erw.cons &&
-                      test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) &&
+                if (!test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags) &&
                     cqr->retries > 0) {
                         DEV_MESSAGE(KERN_DEBUG, device,
                                     "default ERP in fastpath (%i retries left)",
@@ -1742,12 +1741,8 @@ restart:
 
                 /*  Process requests that may be recovered */
                 if (cqr->status == DASD_CQR_NEED_ERP) {
-                        if (cqr->irb.esw.esw0.erw.cons &&
-                            test_bit(DASD_CQR_FLAGS_USE_ERP,
-                                     &cqr->flags)) {
-                                erp_fn = base->discipline->erp_action(cqr);
-                                erp_fn(cqr);
-                        }
+                        erp_fn = base->discipline->erp_action(cqr);
+                        erp_fn(cqr);
                         goto restart;
                 }
 
diff --git a/drivers/s390/block/dasd_3990_erp.c b/drivers/s390/block/dasd_3990_erp.c
index c361ab69ec00..f69714a0e9e7 100644
--- a/drivers/s390/block/dasd_3990_erp.c
+++ b/drivers/s390/block/dasd_3990_erp.c
@@ -164,7 +164,7 @@ dasd_3990_erp_alternate_path(struct dasd_ccw_req * erp)
 
                 /* reset status to submit the request again... */
                 erp->status = DASD_CQR_FILLED;
-                erp->retries = 1;
+                erp->retries = 10;
         } else {
                 DEV_MESSAGE(KERN_ERR, device,
                             "No alternate channel path left (lpum=%x / "
@@ -301,8 +301,7 @@ dasd_3990_erp_action_4(struct dasd_ccw_req * erp, char *sense)
                 erp->function = dasd_3990_erp_action_4;
 
         } else {
-
-                if (sense[25] == 0x1D) {        /* state change pending */
+                if (sense && (sense[25] == 0x1D)) { /* state change pending */
 
                         DEV_MESSAGE(KERN_INFO, device,
                                     "waiting for state change pending "
@@ -311,7 +310,7 @@ dasd_3990_erp_action_4(struct dasd_ccw_req * erp, char *sense)
 
                         dasd_3990_erp_block_queue(erp, 30*HZ);
 
-                } else if (sense[25] == 0x1E) { /* busy */
+                } else if (sense && (sense[25] == 0x1E)) {      /* busy */
                         DEV_MESSAGE(KERN_INFO, device,
                                     "busy - redriving request later, "
                                     "%d retries left",
@@ -2120,6 +2119,34 @@ dasd_3990_erp_inspect_32(struct dasd_ccw_req * erp, char *sense)
  */
 
 /*
+ * DASD_3990_ERP_CONTROL_CHECK
+ *
+ * DESCRIPTION
+ *   Does a generic inspection if a control check occured and sets up
+ *   the related error recovery procedure
+ *
+ * PARAMETER
+ *   erp                pointer to the currently created default ERP
+ *
+ * RETURN VALUES
+ *   erp_filled         pointer to the erp
+ */
+
+static struct dasd_ccw_req *
+dasd_3990_erp_control_check(struct dasd_ccw_req *erp)
+{
+        struct dasd_device *device = erp->startdev;
+
+        if (erp->refers->irb.scsw.cstat & (SCHN_STAT_INTF_CTRL_CHK
+                                           | SCHN_STAT_CHN_CTRL_CHK)) {
+                DEV_MESSAGE(KERN_DEBUG, device, "%s",
+                            "channel or interface control check");
+                erp = dasd_3990_erp_action_4(erp, NULL);
+        }
+        return erp;
+}
+
+/*
  * DASD_3990_ERP_INSPECT
  *
  * DESCRIPTION
@@ -2145,8 +2172,11 @@ dasd_3990_erp_inspect(struct dasd_ccw_req * erp)
         if (erp_new)
                 return erp_new;
 
+        /* check if no concurrent sens is available */
+        if (!erp->refers->irb.esw.esw0.erw.cons)
+                erp_new = dasd_3990_erp_control_check(erp);
         /* distinguish between 24 and 32 byte sense data */
-        if (sense[27] & DASD_SENSE_BIT_0) {
+        else if (sense[27] & DASD_SENSE_BIT_0) {
 
                 /* inspect the 24 byte sense data */
                 erp_new = dasd_3990_erp_inspect_24(erp, sense);
@@ -2285,6 +2315,17 @@ dasd_3990_erp_error_match(struct dasd_ccw_req *cqr1, struct dasd_ccw_req *cqr2)
                 //      return 0;       /* CCW doesn't match */
         }
 
+        if (cqr1->irb.esw.esw0.erw.cons != cqr2->irb.esw.esw0.erw.cons)
+                return 0;
+
+        if ((cqr1->irb.esw.esw0.erw.cons == 0) &&
+            (cqr2->irb.esw.esw0.erw.cons == 0)) {
+                if ((cqr1->irb.scsw.cstat & (SCHN_STAT_INTF_CTRL_CHK |
+                                             SCHN_STAT_CHN_CTRL_CHK)) ==
+                    (cqr2->irb.scsw.cstat & (SCHN_STAT_INTF_CTRL_CHK |
+                                             SCHN_STAT_CHN_CTRL_CHK)))
+                        return 1; /* match with ifcc*/
+        }
         /* check sense data; byte 0-2,25,27 */
         if (!((memcmp (cqr1->irb.ecw, cqr2->irb.ecw, 3) == 0) &&
               (cqr1->irb.ecw[27] == cqr2->irb.ecw[27]) &&
@@ -2560,17 +2601,6 @@ dasd_3990_erp_action(struct dasd_ccw_req * cqr)
 
                 return cqr;
         }
-        /* check if sense data are available */
-        if (!cqr->irb.ecw) {
-                DEV_MESSAGE(KERN_DEBUG, device,
-                            "ERP called witout sense data avail ..."
-                            "request %p - NO ERP possible", cqr);
-
-                cqr->status = DASD_CQR_FAILED;
-
-                return cqr;
-
-        }
 
         /* check if error happened before */
         erp = dasd_3990_erp_in_erp(cqr);