s390/qdio: improve handling of PENDING buffers for QEBSM devices

For QEBSM devices the 'merge_pending' mechanism in get_buf_states()
doesn't apply, and we can actually get SLSB_P_OUTPUT_PENDING returned.

So for this case propagating the PENDING state to the driver via the
queue's sbal_state doesn't make sense and creates unnecessary overhead.
Instead introduce a new QDIO_ERROR_* flag that gets passed to the
driver, and triggers the same processing as if the buffers were flagged
as QDIO_OUTBUF_STATE_FLAG_PENDING.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

3 files changed, 16 insertions, 5 deletions

diff --git a/arch/s390/include/asm/qdio.h b/arch/s390/include/asm/qdio.h
index f96454f5d4cd..c85f75a3d452 100644
--- a/arch/s390/include/asm/qdio.h
+++ b/arch/s390/include/asm/qdio.h
@@ -315,6 +315,7 @@ typedef void qdio_handler_t(struct ccw_device *, unsigned int, int,
 #define QDIO_ERROR_GET_BUF_STATE		0x0002
 #define QDIO_ERROR_SET_BUF_STATE		0x0004
 #define QDIO_ERROR_SLSB_STATE			0x0100
+#define QDIO_ERROR_SLSB_PENDING			0x0200
 
 #define QDIO_ERROR_FATAL			0x00ff
 #define QDIO_ERROR_TEMPORARY			0xff00
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 4252f43ef214..0ad5a4c1bb08 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -571,6 +571,7 @@ static int get_outbound_buffer_frontier(struct qdio_q *q, unsigned int start,
 					unsigned int *error)
 {
 	unsigned char state = 0;
+	unsigned int i;
 	int count;
 
 	q->timestamp = get_tod_clock_fast();
@@ -591,8 +592,14 @@ static int get_outbound_buffer_frontier(struct qdio_q *q, unsigned int start,
 		return 0;
 
 	switch (state) {
-	case SLSB_P_OUTPUT_EMPTY:
 	case SLSB_P_OUTPUT_PENDING:
+		/* detach the utilized QAOBs: */
+		for (i = 0; i < count; i++)
+			q->u.out.aobs[QDIO_BUFNR(start + i)] = NULL;
+
+		*error = QDIO_ERROR_SLSB_PENDING;
+		fallthrough;
+	case SLSB_P_OUTPUT_EMPTY:
 		/* the adapter got it */
 		DBF_DEV_EVENT(DBF_INFO, q->irq_ptr,
 			"out empty:%1d %02x", q->nr, count);
@@ -643,7 +650,7 @@ static inline int qdio_outbound_q_moved(struct qdio_q *q, unsigned int start,
 	if (count) {
 		DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "out moved:%1d", q->nr);
 
-		if (q->u.out.use_cq) {
+		if (q->u.out.use_cq && *error != QDIO_ERROR_SLSB_PENDING) {
 			unsigned int i;
 
 			for (i = 0; i < count; i++)
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index cf18d87da41e..13056cc2377b 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -6068,14 +6068,17 @@ int qeth_poll(struct napi_struct *napi, int budget)
 EXPORT_SYMBOL_GPL(qeth_poll);
 
 static void qeth_iqd_tx_complete(struct qeth_qdio_out_q *queue,
-				 unsigned int bidx, bool error, int budget)
+				 unsigned int bidx, unsigned int qdio_error,
+				 int budget)
 {
 	struct qeth_qdio_out_buffer *buffer = queue->bufs[bidx];
 	u8 sflags = buffer->buffer->element[15].sflags;
 	struct qeth_card *card = queue->card;
+	bool error = !!qdio_error;
 
-	if (queue->bufstates && (queue->bufstates[bidx].flags &
-				 QDIO_OUTBUF_STATE_FLAG_PENDING)) {
+	if ((qdio_error == QDIO_ERROR_SLSB_PENDING) ||
+	    (queue->bufstates && (queue->bufstates[bidx].flags &
+				  QDIO_OUTBUF_STATE_FLAG_PENDING))) {
 		WARN_ON_ONCE(card->options.cq != QETH_CQ_ENABLED);
 
 		QETH_CARD_TEXT_(card, 5, "pel%u", bidx);