[S390] qdio: reset error states immediately

The qdio hardware may surpress further interrupts as long as a SBAL is in
the error state. That can lead to unnotified data in the SBALs following
the error state. To prevent this behaviour change the SBAL[s] in error
state immediately to another program owned state so interrupts are again
received for further traffic on the device.

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

1 files changed, 12 insertions, 5 deletions

diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index c532ba929ccd..e8f267eb8887 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -407,8 +407,11 @@ static inline void account_sbals(struct qdio_q *q, int count)
         q->q_stats.nr_sbals[pos]++;
 }
 
-static void announce_buffer_error(struct qdio_q *q, int count)
+static void process_buffer_error(struct qdio_q *q, int count)
 {
+        unsigned char state = (q->is_input_q) ? SLSB_P_INPUT_NOT_INIT :
+                                        SLSB_P_OUTPUT_NOT_INIT;
+
         q->qdio_error |= QDIO_ERROR_SLSB_STATE;
 
         /* special handling for no target buffer empty */
@@ -426,6 +429,12 @@ static void announce_buffer_error(struct qdio_q *q, int count)
         DBF_ERROR("F14:%2x F15:%2x",
                   q->sbal[q->first_to_check]->element[14].flags & 0xff,
                   q->sbal[q->first_to_check]->element[15].flags & 0xff);
+
+        /*
+         * Interrupts may be avoided as long as the error is present
+         * so change the buffer state immediately to avoid starvation.
+         */
+        set_buf_states(q, q->first_to_check, state, count);
 }
 
 static inline void inbound_primed(struct qdio_q *q, int count)
@@ -506,8 +515,7 @@ static int get_inbound_buffer_frontier(struct qdio_q *q)
                         account_sbals(q, count);
                 break;
         case SLSB_P_INPUT_ERROR:
-                announce_buffer_error(q, count);
-                /* process the buffer, the upper layer will take care of it */
+                process_buffer_error(q, count);
                 q->first_to_check = add_buf(q->first_to_check, count);
                 atomic_sub(count, &q->nr_buf_used);
                 if (q->irq_ptr->perf_stat_enabled)
@@ -677,8 +685,7 @@ static int get_outbound_buffer_frontier(struct qdio_q *q)
                         account_sbals(q, count);
                 break;
         case SLSB_P_OUTPUT_ERROR:
-                announce_buffer_error(q, count);
-                /* process the buffer, the upper layer will take care of it */
+                process_buffer_error(q, count);
                 q->first_to_check = add_buf(q->first_to_check, count);
                 atomic_sub(count, &q->nr_buf_used);
                 if (q->irq_ptr->perf_stat_enabled)