Commit 7c47f5af authored by Julian Wiedmann's avatar Julian Wiedmann Committed by David S. Miller
Browse files

s390/qdio: enable drivers to poll for Output completions 



While commit d36deae7 ("qdio: extend API to allow polling") enhanced
the qdio layer so that drivers can poll their Input Queues, we don't
have the corresponding infrastructure for Output Queues yet.

Factor out a helper that scans a single QDIO Queue, so that qeth can
implement TX NAPI on top of it.
While doing so, remove the duplicated tracking of the next-to-scan index
(q->first_to_check vs q->first_to_kick) in this code path.

qdio_handle_aobs() needs to move slightly upwards in the code hierarchy,
so that it's still called from the polling path.

Signed-off-by: default avatarJulian Wiedmann <jwi@linux.ibm.com>
Acked-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fbbdbc64

arch/s390/include/asm/qdio.h

+3 −0
Original line number Diff line number Diff line
@@ -416,6 +416,9 @@ extern int do_QDIO(struct ccw_device *, unsigned int, int, unsigned int, 
extern int qdio_start_irq(struct ccw_device *, int);

extern int qdio_stop_irq(struct ccw_device *, int);

extern int qdio_get_next_buffers(struct ccw_device *, int, int *, int *);

extern int qdio_inspect_queue(struct ccw_device *cdev, unsigned int nr,

			      bool is_input, unsigned int *bufnr,

			      unsigned int *error);

extern int qdio_shutdown(struct ccw_device *, int);

extern int qdio_free(struct ccw_device *);

extern int qdio_get_ssqd_desc(struct ccw_device *, struct qdio_ssqd_desc *);

drivers/s390/cio/qdio_main.c

+43 −21
Original line number Diff line number Diff line
@@ -647,8 +647,6 @@ static void qdio_kick_handler(struct qdio_q *q, unsigned int count) 
		qperf_inc(q, outbound_handler);

		DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "koh: s:%02x c:%02x",

			      start, count);

		if (q->u.out.use_cq)

			qdio_handle_aobs(q, start, count);

	}



	q->handler(q->irq_ptr->cdev, q->qdio_error, q->nr, start, count,
@@ -774,8 +772,11 @@ static inline int qdio_outbound_q_moved(struct qdio_q *q, unsigned int start) 


	count = get_outbound_buffer_frontier(q, start);



	if (count)

	if (count) {

		DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "out moved:%1d", q->nr);

		if (q->u.out.use_cq)

			qdio_handle_aobs(q, start, count);

	}



	return count;

}
@@ -1655,6 +1656,44 @@ rescan: 
}

EXPORT_SYMBOL(qdio_start_irq);



static int __qdio_inspect_queue(struct qdio_q *q, unsigned int *bufnr,

				unsigned int *error)

{

	unsigned int start = q->first_to_check;

	int count;



	count = q->is_input_q ? qdio_inbound_q_moved(q, start) :

				qdio_outbound_q_moved(q, start);

	if (count == 0)

		return 0;



	*bufnr = start;

	*error = q->qdio_error;



	/* for the next time */

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

	q->qdio_error = 0;



	return count;

}



int qdio_inspect_queue(struct ccw_device *cdev, unsigned int nr, bool is_input,

		       unsigned int *bufnr, unsigned int *error)

{

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

	struct qdio_q *q;



	if (!irq_ptr)

		return -ENODEV;

	q = is_input ? irq_ptr->input_qs[nr] : irq_ptr->output_qs[nr];



	if (need_siga_sync(q))

		qdio_siga_sync_q(q);



	return __qdio_inspect_queue(q, bufnr, error);

}

EXPORT_SYMBOL_GPL(qdio_inspect_queue);



/**

 * qdio_get_next_buffers - process input buffers

 * @cdev: associated ccw_device for the qdio subchannel
@@ -1672,13 +1711,10 @@ int qdio_get_next_buffers(struct ccw_device *cdev, int nr, int *bufnr, 
{

	struct qdio_q *q;

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

	unsigned int start;

	int count;



	if (!irq_ptr)

		return -ENODEV;

	q = irq_ptr->input_qs[nr];

	start = q->first_to_check;



	/*

	 * Cannot rely on automatic sync after interrupt since queues may
@@ -1689,25 +1725,11 @@ int qdio_get_next_buffers(struct ccw_device *cdev, int nr, int *bufnr, 


	qdio_check_outbound_pci_queues(irq_ptr);



	count = qdio_inbound_q_moved(q, start);

	if (count == 0)

		return 0;



	start = add_buf(start, count);

	q->first_to_check = start;



	/* Note: upper-layer MUST stop processing immediately here ... */

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

		return -EIO;



	*bufnr = q->first_to_kick;

	*error = q->qdio_error;



	/* for the next time */

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

	q->qdio_error = 0;



	return count;

	return __qdio_inspect_queue(q, bufnr, error);

}

EXPORT_SYMBOL(qdio_get_next_buffers);

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