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Commit 25f269f1 authored by Jan Glauber's avatar Jan Glauber Committed by Martin Schwidefsky
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[S390] qdio: EQBS retry after CCQ 96 



Running under z/VM with QIOASSIST enabled, qdio queues could stall if EQBS
did not extract all SBAL states. Add an instant retry for EQBS and, if the
retry fails, set up a timer to ensure outstanding SBALs are processed later.

While at it, optimize qdio_do_eqbs and qdio_do_sqbs to eliminate 3 jumps on
the hot path.

Signed-off-by: default avatarJan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent a2b86019

drivers/s390/cio/qdio_main.c

+41 −40
Original line number Diff line number Diff line
@@ -104,9 +104,12 @@ static inline int qdio_check_ccq(struct qdio_q *q, unsigned int ccq) 
	/* all done or next buffer state different */

	if (ccq == 0 || ccq == 32)

		return 0;

	/* not all buffers processed */

	if (ccq == 96 || ccq == 97)

	/* no buffer processed */

	if (ccq == 97)

		return 1;

	/* not all buffers processed */

	if (ccq == 96)

		return 2;

	/* notify devices immediately */

	DBF_ERROR("%4x ccq:%3d", SCH_NO(q), ccq);

	return -EIO;
@@ -126,10 +129,8 @@ static inline int qdio_check_ccq(struct qdio_q *q, unsigned int ccq) 
static int qdio_do_eqbs(struct qdio_q *q, unsigned char *state,

			int start, int count, int auto_ack)

{

	int rc, tmp_count = count, tmp_start = start, nr = q->nr, retried = 0;

	unsigned int ccq = 0;

	int tmp_count = count, tmp_start = start;

	int nr = q->nr;

	int rc;



	BUG_ON(!q->irq_ptr->sch_token);

	qperf_inc(q, eqbs);
@@ -140,31 +141,35 @@ static int qdio_do_eqbs(struct qdio_q *q, unsigned char *state, 
	ccq = do_eqbs(q->irq_ptr->sch_token, state, nr, &tmp_start, &tmp_count,

		      auto_ack);

	rc = qdio_check_ccq(q, ccq);



	/* At least one buffer was processed, return and extract the remaining

	 * buffers later.

	 */

	if ((ccq == 96) && (count != tmp_count)) {

		qperf_inc(q, eqbs_partial);

		return (count - tmp_count);

	}

	if (!rc)

		return count - tmp_count;



	if (rc == 1) {

		DBF_DEV_EVENT(DBF_WARN, q->irq_ptr, "EQBS again:%2d", ccq);

		goto again;

	}



	if (rc < 0) {

	if (rc == 2) {

		BUG_ON(tmp_count == count);

		qperf_inc(q, eqbs_partial);

		DBF_DEV_EVENT(DBF_WARN, q->irq_ptr, "EQBS part:%02x",

			tmp_count);

		/*

		 * Retry once, if that fails bail out and process the

		 * extracted buffers before trying again.

		 */

		if (!retried++)

			goto again;

		else

			return count - tmp_count;

	}



	DBF_ERROR("%4x EQBS ERROR", SCH_NO(q));

	DBF_ERROR("%3d%3d%2d", count, tmp_count, nr);

		q->handler(q->irq_ptr->cdev,

			   QDIO_ERROR_ACTIVATE_CHECK_CONDITION,

			   q->nr, q->first_to_kick, count,

			   q->irq_ptr->int_parm);

	q->handler(q->irq_ptr->cdev, QDIO_ERROR_ACTIVATE_CHECK_CONDITION,

		   0, -1, -1, q->irq_ptr->int_parm);

	return 0;

}

	return count - tmp_count;

}



/**

 * qdio_do_sqbs - set buffer states for QEBSM
@@ -196,23 +201,23 @@ static int qdio_do_sqbs(struct qdio_q *q, unsigned char state, int start, 
again:

	ccq = do_sqbs(q->irq_ptr->sch_token, state, nr, &tmp_start, &tmp_count);

	rc = qdio_check_ccq(q, ccq);

	if (rc == 1) {

	if (!rc) {

		WARN_ON(tmp_count);

		return count - tmp_count;

	}



	if (rc == 1 || rc == 2) {

		DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "SQBS again:%2d", ccq);

		qperf_inc(q, sqbs_partial);

		goto again;

	}

	if (rc < 0) {



	DBF_ERROR("%4x SQBS ERROR", SCH_NO(q));

	DBF_ERROR("%3d%3d%2d", count, tmp_count, nr);

		q->handler(q->irq_ptr->cdev,

			   QDIO_ERROR_ACTIVATE_CHECK_CONDITION,

			   q->nr, q->first_to_kick, count,

			   q->irq_ptr->int_parm);

	q->handler(q->irq_ptr->cdev, QDIO_ERROR_ACTIVATE_CHECK_CONDITION,

		   0, -1, -1, q->irq_ptr->int_parm);

	return 0;

}

	WARN_ON(tmp_count);

	return count - tmp_count;

}



/* returns number of examined buffers and their common state in *state */

static inline int get_buf_states(struct qdio_q *q, unsigned int bufnr,
@@ -915,10 +920,6 @@ static void __qdio_outbound_processing(struct qdio_q *q) 
		if (!pci_out_supported(q) && !qdio_outbound_q_done(q))

			goto sched;



	/* bail out for HiperSockets unicast queues */

	if (queue_type(q) == QDIO_IQDIO_QFMT && !multicast_outbound(q))

		return;



	if ((queue_type(q) == QDIO_IQDIO_QFMT) &&

	    (atomic_read(&q->nr_buf_used)) > QDIO_IQDIO_POLL_LVL)

		goto sched;
@@ -928,8 +929,8 @@ static void __qdio_outbound_processing(struct qdio_q *q) 


	/*

	 * Now we know that queue type is either qeth without pci enabled

	 * or HiperSockets multicast. Make sure buffer switch from PRIMED to

	 * EMPTY is noticed and outbound_handler is called after some time.

	 * or HiperSockets. Make sure buffer switch from PRIMED to EMPTY

	 * is noticed and outbound_handler is called after some time.

	 */

	if (qdio_outbound_q_done(q))

		del_timer(&q->u.out.timer);