linux-kernel - [PATCH 1/7] s390/vfio-ap: verify reset complete in separate function

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Date:   Tue, 13 Dec 2022 10:44:31 -0500
From:   Tony Krowiak <akrowiak@...ux.ibm.com>
To:     linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     jjherne@...ux.ibm.com, freude@...ux.ibm.com,
        borntraeger@...ibm.com, cohuck@...hat.com, mjrosato@...ux.ibm.com,
        pasic@...ux.ibm.com, alex.williamson@...hat.com,
        kwankhede@...dia.com, fiuczy@...ux.ibm.com
Subject: [PATCH 1/7] s390/vfio-ap: verify reset complete in separate function

The vfio_ap_mdev_reset_queue() function contains a loop to verify that the
reset successfully completes within 40ms. This patch moves that loop into
a separate function.

Signed-off-by: Tony Krowiak <akrowiak@...ux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_ops.c | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 0b4cc8c597ae..83ff94a38102 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1587,12 +1587,30 @@ static struct vfio_ap_queue *vfio_ap_find_queue(int apqn)
 	return q;
 }
 
+static int apq_reset_check(struct vfio_ap_queue *q)
+{
+	int iters = 2;
+	struct ap_queue_status status;
+
+	while (iters--) {
+		msleep(20);
+		status = ap_tapq(q->apqn, NULL);
+		if (status.queue_empty && !status.irq_enabled)
+			return 0;
+	}
+	WARN_ONCE(iters <= 0,
+		  "timeout verifying reset of queue %02x.%04x (%u, %u, %u)",
+		  AP_QID_CARD(q->apqn), AP_QID_QUEUE(q->apqn),
+		  status.queue_empty, status.irq_enabled, status.response_code);
+
+	return -EBUSY;
+}
+
 static int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q,
 				    unsigned int retry)
 {
 	struct ap_queue_status status;
 	int ret;
-	int retry2 = 2;
 
 	if (!q)
 		return 0;
@@ -1629,14 +1647,8 @@ static int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q,
 	}
 
 	/* wait for the reset to take effect */
-	while (retry2--) {
-		if (status.queue_empty && !status.irq_enabled)
-			break;
-		msleep(20);
-		status = ap_tapq(q->apqn, NULL);
-	}
-	WARN_ONCE(retry2 <= 0, "unable to verify reset of queue %02x.%04x",
-		  AP_QID_CARD(q->apqn), AP_QID_QUEUE(q->apqn));
+	if (!status.queue_empty && status.irq_enabled)
+		ret = apq_reset_check(q);
 
 free_resources:
 	vfio_ap_free_aqic_resources(q);
-- 
2.31.1