[S390] qdio: report SIGA errors directly

Errors from SIGA instructions are stored in the per queue qdio_error
and reported back when the queue handler is called. That opens a race
when multiple error conditions occur simultanously.

Report SIGA errors immediately in the return value of do_QDIO so the
upper layer can react and SIGA errors no longer interfere with other
errors.

Move the SIGA error handling in qeth from the outbound handler to
qeth_flush_buffers.

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

4 files changed, 47 insertions, 83 deletions

diff --git a/drivers/s390/cio/qdio.h b/drivers/s390/cio/qdio.h
index 57807f5ffe84..41171d741f38 100644
--- a/drivers/s390/cio/qdio.h
+++ b/drivers/s390/cio/qdio.h
@@ -247,7 +247,6 @@ struct qdio_q {
 
         struct qdio_irq *irq_ptr;
         struct tasklet_struct tasklet;
-        spinlock_t lock;
 
         /* error condition during a data transfer */
         unsigned int qdio_error;
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 31b9318149ba..e53ac67e1e48 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -706,13 +706,13 @@ static inline int qdio_outbound_q_moved(struct qdio_q *q)
                 return 0;
 }
 
-static void qdio_kick_outbound_q(struct qdio_q *q)
+static int qdio_kick_outbound_q(struct qdio_q *q)
 {
         unsigned int busy_bit;
         int cc;
 
         if (!need_siga_out(q))
-                return;
+                return 0;
 
         DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w:%1d", q->nr);
         qdio_perf_stat_inc(&perf_stats.siga_out);
@@ -724,19 +724,16 @@ static void qdio_kick_outbound_q(struct qdio_q *q)
         case 2:
                 if (busy_bit) {
                         DBF_ERROR("%4x cc2 REP:%1d", SCH_NO(q), q->nr);
-                        q->qdio_error = cc | QDIO_ERROR_SIGA_BUSY;
-                } else {
-                        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w cc2:%1d",
-                                      q->nr);
-                        q->qdio_error = cc;
-                }
+                        cc |= QDIO_ERROR_SIGA_BUSY;
+                } else
+                        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w cc2:%1d", q->nr);
                 break;
         case 1:
         case 3:
                 DBF_ERROR("%4x SIGA-W:%1d", SCH_NO(q), cc);
-                q->qdio_error = cc;
                 break;
         }
+        return cc;
 }
 
 static void qdio_kick_outbound_handler(struct qdio_q *q)
@@ -766,18 +763,12 @@ static void qdio_kick_outbound_handler(struct qdio_q *q)
 
 static void __qdio_outbound_processing(struct qdio_q *q)
 {
-        unsigned long flags;
-
         qdio_perf_stat_inc(&perf_stats.tasklet_outbound);
-        spin_lock_irqsave(&q->lock, flags);
-
         BUG_ON(atomic_read(&q->nr_buf_used) < 0);
 
         if (qdio_outbound_q_moved(q))
                 qdio_kick_outbound_handler(q);
 
-        spin_unlock_irqrestore(&q->lock, flags);
-
         if (queue_type(q) == QDIO_ZFCP_QFMT)
                 if (!pci_out_supported(q) && !qdio_outbound_q_done(q))
                         goto sched;
@@ -1457,10 +1448,10 @@ static inline int buf_in_between(int bufnr, int start, int count)
  * @bufnr: first buffer to process
  * @count: how many buffers are emptied
  */
-static void handle_inbound(struct qdio_q *q, unsigned int callflags,
-                           int bufnr, int count)
+static int handle_inbound(struct qdio_q *q, unsigned int callflags,
+                          int bufnr, int count)
 {
-        int used, cc, diff;
+        int used, diff;
 
         if (!q->u.in.polling)
                 goto set;
@@ -1497,13 +1488,11 @@ set:
 
         /* no need to signal as long as the adapter had free buffers */
         if (used)
-                return;
+                return 0;
 
-        if (need_siga_in(q)) {
-                cc = qdio_siga_input(q);
-                if (cc)
-                        q->qdio_error = cc;
-        }
+        if (need_siga_in(q))
+                return qdio_siga_input(q);
+        return 0;
 }
 
 /**
@@ -1513,11 +1502,11 @@ set:
  * @bufnr: first buffer to process
  * @count: how many buffers are filled
  */
-static void handle_outbound(struct qdio_q *q, unsigned int callflags,
-                            int bufnr, int count)
+static int handle_outbound(struct qdio_q *q, unsigned int callflags,
+                           int bufnr, int count)
 {
         unsigned char state;
-        int used;
+        int used, rc = 0;
 
         qdio_perf_stat_inc(&perf_stats.outbound_handler);
 
@@ -1532,27 +1521,26 @@ static void handle_outbound(struct qdio_q *q, unsigned int callflags,
 
         if (queue_type(q) == QDIO_IQDIO_QFMT) {
                 if (multicast_outbound(q))
-                        qdio_kick_outbound_q(q);
+                        rc = qdio_kick_outbound_q(q);
                 else
                         if ((q->irq_ptr->ssqd_desc.mmwc > 1) &&
                             (count > 1) &&
                             (count <= q->irq_ptr->ssqd_desc.mmwc)) {
                                 /* exploit enhanced SIGA */
                                 q->u.out.use_enh_siga = 1;
-                                qdio_kick_outbound_q(q);
+                                rc = qdio_kick_outbound_q(q);
                         } else {
                                 /*
                                 * One siga-w per buffer required for unicast
                                 * HiperSockets.
                                 */
                                 q->u.out.use_enh_siga = 0;
-                                while (count--)
-                                        qdio_kick_outbound_q(q);
+                                while (count--) {
+                                        rc = qdio_kick_outbound_q(q);
+                                        if (rc)
+                                                goto out;
+                                }
                         }
-
-                /* report CC=2 conditions synchronously */
-                if (q->qdio_error)
-                        __qdio_outbound_processing(q);
                 goto out;
         }
 
@@ -1564,13 +1552,14 @@ static void handle_outbound(struct qdio_q *q, unsigned int callflags,
         /* try to fast requeue buffers */
         get_buf_state(q, prev_buf(bufnr), &state, 0);
         if (state != SLSB_CU_OUTPUT_PRIMED)
-                qdio_kick_outbound_q(q);
+                rc = qdio_kick_outbound_q(q);
         else {
                 DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "fast-req");
                 qdio_perf_stat_inc(&perf_stats.fast_requeue);
         }
 out:
         tasklet_schedule(&q->tasklet);
+        return rc;
 }
 
 /**
@@ -1609,14 +1598,12 @@ int do_QDIO(struct ccw_device *cdev, unsigned int callflags,
                 return -EBUSY;
 
         if (callflags & QDIO_FLAG_SYNC_INPUT)
-                handle_inbound(irq_ptr->input_qs[q_nr], callflags, bufnr,
-                               count);
+                return handle_inbound(irq_ptr->input_qs[q_nr],
+                                      callflags, bufnr, count);
         else if (callflags & QDIO_FLAG_SYNC_OUTPUT)
-                handle_outbound(irq_ptr->output_qs[q_nr], callflags, bufnr,
-                                count);
-        else
-                return -EINVAL;
-        return 0;
+                return handle_outbound(irq_ptr->output_qs[q_nr],
+                                       callflags, bufnr, count);
+        return -EINVAL;
 }
 EXPORT_SYMBOL_GPL(do_QDIO);
 
diff --git a/drivers/s390/cio/qdio_setup.c b/drivers/s390/cio/qdio_setup.c
index c08356b95bf5..18d54fc21ce9 100644
--- a/drivers/s390/cio/qdio_setup.c
+++ b/drivers/s390/cio/qdio_setup.c
@@ -117,7 +117,6 @@ static void setup_queues_misc(struct qdio_q *q, struct qdio_irq *irq_ptr,
         q->mask = 1 << (31 - i);
         q->nr = i;
         q->handler = handler;
-        spin_lock_init(&q->lock);
 }
 
 static void setup_storage_lists(struct qdio_q *q, struct qdio_irq *irq_ptr,
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index d1b5bebea7fb..2489bcebf5ec 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -2693,40 +2693,21 @@ static int qeth_handle_send_error(struct qeth_card *card,
                 struct qeth_qdio_out_buffer *buffer, unsigned int qdio_err)
 {
         int sbalf15 = buffer->buffer->element[15].flags & 0xff;
-        int cc = qdio_err & 3;
 
         QETH_DBF_TEXT(TRACE, 6, "hdsnderr");
         qeth_check_qdio_errors(buffer->buffer, qdio_err, "qouterr");
-        switch (cc) {
-        case 0:
-                if (qdio_err) {
-                        QETH_DBF_TEXT(TRACE, 1, "lnkfail");
-                        QETH_DBF_TEXT_(TRACE, 1, "%s", CARD_BUS_ID(card));
-                        QETH_DBF_TEXT_(TRACE, 1, "%04x %02x",
-                                       (u16)qdio_err, (u8)sbalf15);
-                        return QETH_SEND_ERROR_LINK_FAILURE;
-                }
+
+        if (!qdio_err)
                 return QETH_SEND_ERROR_NONE;
-        case 2:
-                if (qdio_err & QDIO_ERROR_SIGA_BUSY) {
-                        QETH_DBF_TEXT(TRACE, 1, "SIGAcc2B");
-                        QETH_DBF_TEXT_(TRACE, 1, "%s", CARD_BUS_ID(card));
-                        return QETH_SEND_ERROR_KICK_IT;
-                }
-                if ((sbalf15 >= 15) && (sbalf15 <= 31))
-                        return QETH_SEND_ERROR_RETRY;
-                return QETH_SEND_ERROR_LINK_FAILURE;
-                /* look at qdio_error and sbalf 15 */
-        case 1:
-                QETH_DBF_TEXT(TRACE, 1, "SIGAcc1");
-                QETH_DBF_TEXT_(TRACE, 1, "%s", CARD_BUS_ID(card));
-                return QETH_SEND_ERROR_LINK_FAILURE;
-        case 3:
-        default:
-                QETH_DBF_TEXT(TRACE, 1, "SIGAcc3");
-                QETH_DBF_TEXT_(TRACE, 1, "%s", CARD_BUS_ID(card));
-                return QETH_SEND_ERROR_KICK_IT;
-        }
+
+        if ((sbalf15 >= 15) && (sbalf15 <= 31))
+                return QETH_SEND_ERROR_RETRY;
+
+        QETH_DBF_TEXT(TRACE, 1, "lnkfail");
+        QETH_DBF_TEXT_(TRACE, 1, "%s", CARD_BUS_ID(card));
+        QETH_DBF_TEXT_(TRACE, 1, "%04x %02x",
+                       (u16)qdio_err, (u8)sbalf15);
+        return QETH_SEND_ERROR_LINK_FAILURE;
 }
 
 /*
@@ -2862,10 +2843,14 @@ static void qeth_flush_buffers(struct qeth_qdio_out_q *queue, int index,
                         qeth_get_micros() -
                         queue->card->perf_stats.outbound_do_qdio_start_time;
         if (rc) {
+                queue->card->stats.tx_errors += count;
+                /* ignore temporary SIGA errors without busy condition */
+                if (rc == QDIO_ERROR_SIGA_TARGET)
+                        return;
                 QETH_DBF_TEXT(TRACE, 2, "flushbuf");
                 QETH_DBF_TEXT_(TRACE, 2, " err%d", rc);
                 QETH_DBF_TEXT_(TRACE, 2, "%s", CARD_DDEV_ID(queue->card));
-                queue->card->stats.tx_errors += count;
+
                 /* this must not happen under normal circumstances. if it
                  * happens something is really wrong -> recover */
                 qeth_schedule_recovery(queue->card);
@@ -2940,13 +2925,7 @@ void qeth_qdio_output_handler(struct ccw_device *ccwdev,
         }
         for (i = first_element; i < (first_element + count); ++i) {
                 buffer = &queue->bufs[i % QDIO_MAX_BUFFERS_PER_Q];
-                /*we only handle the KICK_IT error by doing a recovery */
-                if (qeth_handle_send_error(card, buffer, qdio_error)
-                                == QETH_SEND_ERROR_KICK_IT){
-                        netif_stop_queue(card->dev);
-                        qeth_schedule_recovery(card);
-                        return;
-                }
+                qeth_handle_send_error(card, buffer, qdio_error);
                 qeth_clear_output_buffer(queue, buffer);
         }
         atomic_sub(count, &queue->used_buffers);