[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>

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)