Commit 65e4f776 authored by Julian Wiedmann's avatar Julian Wiedmann Committed by Martin Schwidefsky
Browse files

s390/qdio: simplify SBAL range calculation 



When passing a range of ready-to-process SBALs to the upper-layer
driver, use the available 'count' instead of calculating the distance
between the first_to_check and first_to_kick cursors.

This simplifies the logic of the queue-scan path, and opens up the
possibility of scanning all 128 SBALs in one go (as determining the
reported count no longer requires wrap-around safe arithmetic on the
queue's cursors).

Signed-off-by: default avatarJulian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: default avatarJens Remus <jremus@linux.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent b39544c6

drivers/s390/cio/qdio_main.c

+9 −15
Original line number Diff line number Diff line
@@ -636,17 +636,13 @@ static inline unsigned long qdio_aob_for_buffer(struct qdio_output_q *q, 
	return phys_aob;

}



static void qdio_kick_handler(struct qdio_q *q)

static void qdio_kick_handler(struct qdio_q *q, unsigned int count)

{

	int start = q->first_to_kick;

	int end = q->first_to_check;

	int count;



	if (unlikely(q->irq_ptr->state != QDIO_IRQ_STATE_ACTIVE))

		return;



	count = sub_buf(end, start);



	if (q->is_input_q) {

		qperf_inc(q, inbound_handler);

		DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "kih s:%02x c:%02x", start, count);
@@ -662,7 +658,7 @@ static void qdio_kick_handler(struct qdio_q *q) 
		   q->irq_ptr->int_parm);



	/* for the next time */

	q->first_to_kick = end;

	q->first_to_kick = add_buf(start, count);

	q->qdio_error = 0;

}
@@ -685,7 +681,7 @@ static void __qdio_inbound_processing(struct qdio_q *q) 
	if (count == 0)

		return;



	qdio_kick_handler(q);

	qdio_kick_handler(q, count);



	if (!qdio_inbound_q_done(q)) {

		/* means poll time is not yet over */
@@ -843,7 +839,7 @@ static void __qdio_outbound_processing(struct qdio_q *q) 


	count = qdio_outbound_q_moved(q);

	if (count)

		qdio_kick_handler(q);

		qdio_kick_handler(q, count);



	if (queue_type(q) == QDIO_ZFCP_QFMT && !pci_out_supported(q->irq_ptr) &&

	    !qdio_outbound_q_done(q))
@@ -911,7 +907,7 @@ static void __tiqdio_inbound_processing(struct qdio_q *q) 
	if (count == 0)

		return;



	qdio_kick_handler(q);

	qdio_kick_handler(q, count);



	if (!qdio_inbound_q_done(q)) {

		qperf_inc(q, tasklet_inbound_resched);
@@ -1674,7 +1670,6 @@ int qdio_get_next_buffers(struct ccw_device *cdev, int nr, int *bufnr, 
			  int *error)

{

	struct qdio_q *q;

	int start, end;

	struct qdio_irq *irq_ptr = cdev->private->qdio_data;

	int count;
@@ -1699,15 +1694,14 @@ int qdio_get_next_buffers(struct ccw_device *cdev, int nr, int *bufnr, 
	if (unlikely(q->irq_ptr->state != QDIO_IRQ_STATE_ACTIVE))

		return -EIO;



	start = q->first_to_kick;

	end = q->first_to_check;

	*bufnr = start;

	*bufnr = q->first_to_kick;

	*error = q->qdio_error;



	/* for the next time */

	q->first_to_kick = end;

	q->first_to_kick = add_buf(q->first_to_kick, count);

	q->qdio_error = 0;

	return sub_buf(end, start);



	return count;

}

EXPORT_SYMBOL(qdio_get_next_buffers);

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