From: Julian Wiedmann <jwi@linux.ibm.com>
Date: Wed, 18 Dec 2019 17:34:42 +0100
Subject: s390/qeth: only handle IRQs while device is online
Git-commit: 871602b1079234b2a9279062eaeadb3aad7bc863
Patch-mainline: v5.6-rc1
References: jsc#SLE-13690

A qeth device that's offline should not be receiving any IRQs - all
pending IOs have been terminated, and we avoid starting any new ones.

So rather than immediately registering the IRQ handler when the device
is probed, only register it while the device is online.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/s390/net/qeth_core_main.c |   68 +++++++++++++++++---------------------
 1 file changed, 31 insertions(+), 37 deletions(-)

--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -972,8 +972,6 @@ static void qeth_irq(struct ccw_device *
 	/* while we hold the ccwdev lock, this stays valid: */
 	gdev = dev_get_drvdata(&cdev->dev);
 	card = dev_get_drvdata(&gdev->dev);
-	if (!card)
-		return;
 
 	QETH_CARD_TEXT(card, 5, "irq");
 
@@ -1198,31 +1196,6 @@ static void qeth_free_buffer_pool(struct
 	}
 }
 
-static void qeth_clean_channel(struct qeth_channel *channel)
-{
-	struct ccw_device *cdev = channel->ccwdev;
-
-	QETH_DBF_TEXT(SETUP, 2, "freech");
-
-	spin_lock_irq(get_ccwdev_lock(cdev));
-	cdev->handler = NULL;
-	spin_unlock_irq(get_ccwdev_lock(cdev));
-}
-
-static void qeth_setup_channel(struct qeth_channel *channel)
-{
-	struct ccw_device *cdev = channel->ccwdev;
-
-	QETH_DBF_TEXT(SETUP, 2, "setupch");
-
-	channel->state = CH_STATE_DOWN;
-	atomic_set(&channel->irq_pending, 0);
-
-	spin_lock_irq(get_ccwdev_lock(cdev));
-	cdev->handler = qeth_irq;
-	spin_unlock_irq(get_ccwdev_lock(cdev));
-}
-
 static int qeth_osa_set_output_queues(struct qeth_card *card, bool single)
 {
 	unsigned int count = single ? 1 : card->dev->num_tx_queues;
@@ -1395,9 +1368,6 @@ static struct qeth_card *qeth_alloc_card
 	if (!card->read_cmd)
 		goto out_read_cmd;
 
-	qeth_setup_channel(&card->read);
-	qeth_setup_channel(&card->write);
-	qeth_setup_channel(&card->data);
 	card->qeth_service_level.seq_print = qeth_core_sl_print;
 	register_service_level(&card->qeth_service_level);
 	return card;
@@ -1467,12 +1437,38 @@ int qeth_stop_channel(struct qeth_channe
 			channel->active_cmd);
 		channel->active_cmd = NULL;
 	}
+	cdev->handler = NULL;
 	spin_unlock_irq(get_ccwdev_lock(cdev));
 
 	return rc;
 }
 EXPORT_SYMBOL_GPL(qeth_stop_channel);
 
+static int qeth_start_channel(struct qeth_channel *channel)
+{
+	struct ccw_device *cdev = channel->ccwdev;
+	int rc;
+
+	channel->state = CH_STATE_DOWN;
+	atomic_set(&channel->irq_pending, 0);
+
+	spin_lock_irq(get_ccwdev_lock(cdev));
+	cdev->handler = qeth_irq;
+	spin_unlock_irq(get_ccwdev_lock(cdev));
+
+	rc = ccw_device_set_online(cdev);
+	if (rc)
+		goto err;
+
+	return 0;
+
+err:
+	spin_lock_irq(get_ccwdev_lock(cdev));
+	cdev->handler = NULL;
+	spin_unlock_irq(get_ccwdev_lock(cdev));
+	return rc;
+}
+
 static int qeth_halt_channels(struct qeth_card *card)
 {
 	int rc1 = 0, rc2 = 0, rc3 = 0;
@@ -4697,7 +4693,7 @@ static void qeth_determine_capabilities(
 	QETH_CARD_TEXT(card, 2, "detcapab");
 	if (!ddev->online) {
 		ddev_offline = 1;
-		rc = ccw_device_set_online(ddev);
+		rc = qeth_start_channel(channel);
 		if (rc) {
 			QETH_CARD_TEXT_(card, 2, "3err%d", rc);
 			goto out;
@@ -4872,9 +4868,6 @@ out_free_nothing:
 static void qeth_core_free_card(struct qeth_card *card)
 {
 	QETH_CARD_TEXT(card, 2, "freecrd");
-	qeth_clean_channel(&card->read);
-	qeth_clean_channel(&card->write);
-	qeth_clean_channel(&card->data);
 	qeth_put_cmd(card->read_cmd);
 	destroy_workqueue(card->event_wq);
 	unregister_service_level(&card->qeth_service_level);
@@ -4937,13 +4930,14 @@ retry:
 	qeth_stop_channel(&card->write);
 	qeth_stop_channel(&card->read);
 	qdio_free(CARD_DDEV(card));
-	rc = ccw_device_set_online(CARD_RDEV(card));
+
+	rc = qeth_start_channel(&card->read);
 	if (rc)
 		goto retriable;
-	rc = ccw_device_set_online(CARD_WDEV(card));
+	rc = qeth_start_channel(&card->write);
 	if (rc)
 		goto retriable;
-	rc = ccw_device_set_online(CARD_DDEV(card));
+	rc = qeth_start_channel(&card->data);
 	if (rc)
 		goto retriable;
 retriable: