[S390] qdio: EQBS retry after CCQ 96

Running under z/VM with QIOASSIST enabled, qdio queues could stall if EQBS
did not extract all SBAL states. Add an instant retry for EQBS and, if the
retry fails, set up a timer to ensure outstanding SBALs are processed later.

While at it, optimize qdio_do_eqbs and qdio_do_sqbs to eliminate 3 jumps on
the hot path.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 41 insertions, 40 deletions

diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index a76d6764ce67..7c567b2268a7 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -104,9 +104,12 @@ static inline int qdio_check_ccq(struct qdio_q *q, unsigned int ccq)
         /* all done or next buffer state different */
         if (ccq == 0 || ccq == 32)
                 return 0;
-        /* not all buffers processed */
-        if (ccq == 96 || ccq == 97)
+        /* no buffer processed */
+        if (ccq == 97)
                 return 1;
+        /* not all buffers processed */
+        if (ccq == 96)
+                return 2;
         /* notify devices immediately */
         DBF_ERROR("%4x ccq:%3d", SCH_NO(q), ccq);
         return -EIO;
@@ -126,10 +129,8 @@ static inline int qdio_check_ccq(struct qdio_q *q, unsigned int ccq)
 static int qdio_do_eqbs(struct qdio_q *q, unsigned char *state,
                         int start, int count, int auto_ack)
 {
+        int rc, tmp_count = count, tmp_start = start, nr = q->nr, retried = 0;
         unsigned int ccq = 0;
-        int tmp_count = count, tmp_start = start;
-        int nr = q->nr;
-        int rc;
 
         BUG_ON(!q->irq_ptr->sch_token);
         qperf_inc(q, eqbs);
@@ -140,30 +141,34 @@ again:
         ccq = do_eqbs(q->irq_ptr->sch_token, state, nr, &tmp_start, &tmp_count,
                       auto_ack);
         rc = qdio_check_ccq(q, ccq);
-
-        /* At least one buffer was processed, return and extract the remaining
-         * buffers later.
-         */
-        if ((ccq == 96) && (count != tmp_count)) {
-                qperf_inc(q, eqbs_partial);
-                return (count - tmp_count);
-        }
+        if (!rc)
+                return count - tmp_count;
 
         if (rc == 1) {
                 DBF_DEV_EVENT(DBF_WARN, q->irq_ptr, "EQBS again:%2d", ccq);
                 goto again;
         }
 
-        if (rc < 0) {
-                DBF_ERROR("%4x EQBS ERROR", SCH_NO(q));
-                DBF_ERROR("%3d%3d%2d", count, tmp_count, nr);
-                q->handler(q->irq_ptr->cdev,
-                           QDIO_ERROR_ACTIVATE_CHECK_CONDITION,
-                           q->nr, q->first_to_kick, count,
-                           q->irq_ptr->int_parm);
-                return 0;
+        if (rc == 2) {
+                BUG_ON(tmp_count == count);
+                qperf_inc(q, eqbs_partial);
+                DBF_DEV_EVENT(DBF_WARN, q->irq_ptr, "EQBS part:%02x",
+                        tmp_count);
+                /*
+                 * Retry once, if that fails bail out and process the
+                 * extracted buffers before trying again.
+                 */
+                if (!retried++)
+                        goto again;
+                else
+                        return count - tmp_count;
         }
-        return count - tmp_count;
+
+        DBF_ERROR("%4x EQBS ERROR", SCH_NO(q));
+        DBF_ERROR("%3d%3d%2d", count, tmp_count, nr);
+        q->handler(q->irq_ptr->cdev, QDIO_ERROR_ACTIVATE_CHECK_CONDITION,
+                   0, -1, -1, q->irq_ptr->int_parm);
+        return 0;
 }
 
 /**
@@ -196,22 +201,22 @@ static int qdio_do_sqbs(struct qdio_q *q, unsigned char state, int start,
 again:
         ccq = do_sqbs(q->irq_ptr->sch_token, state, nr, &tmp_start, &tmp_count);
         rc = qdio_check_ccq(q, ccq);
-        if (rc == 1) {
+        if (!rc) {
+                WARN_ON(tmp_count);
+                return count - tmp_count;
+        }
+
+        if (rc == 1 || rc == 2) {
                 DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "SQBS again:%2d", ccq);
                 qperf_inc(q, sqbs_partial);
                 goto again;
         }
-        if (rc < 0) {
-                DBF_ERROR("%4x SQBS ERROR", SCH_NO(q));
-                DBF_ERROR("%3d%3d%2d", count, tmp_count, nr);
-                q->handler(q->irq_ptr->cdev,
-                           QDIO_ERROR_ACTIVATE_CHECK_CONDITION,
-                           q->nr, q->first_to_kick, count,
-                           q->irq_ptr->int_parm);
-                return 0;
-        }
-        WARN_ON(tmp_count);
-        return count - tmp_count;
+
+        DBF_ERROR("%4x SQBS ERROR", SCH_NO(q));
+        DBF_ERROR("%3d%3d%2d", count, tmp_count, nr);
+        q->handler(q->irq_ptr->cdev, QDIO_ERROR_ACTIVATE_CHECK_CONDITION,
+                   0, -1, -1, q->irq_ptr->int_parm);
+        return 0;
 }
 
 /* returns number of examined buffers and their common state in *state */
@@ -915,10 +920,6 @@ static void __qdio_outbound_processing(struct qdio_q *q)
                 if (!pci_out_supported(q) && !qdio_outbound_q_done(q))
                         goto sched;
 
-        /* bail out for HiperSockets unicast queues */
-        if (queue_type(q) == QDIO_IQDIO_QFMT && !multicast_outbound(q))
-                return;
-
         if ((queue_type(q) == QDIO_IQDIO_QFMT) &&
             (atomic_read(&q->nr_buf_used)) > QDIO_IQDIO_POLL_LVL)
                 goto sched;
@@ -928,8 +929,8 @@ static void __qdio_outbound_processing(struct qdio_q *q)
 
         /*
          * Now we know that queue type is either qeth without pci enabled
-         * or HiperSockets multicast. Make sure buffer switch from PRIMED to
-         * EMPTY is noticed and outbound_handler is called after some time.
+         * or HiperSockets. Make sure buffer switch from PRIMED to EMPTY
+         * is noticed and outbound_handler is called after some time.
          */
         if (qdio_outbound_q_done(q))
                 del_timer(&q->u.out.timer);