netdev - [PATCH net-next 4/9] s390/qeth: keep cmd alive after IO completion

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Date:   Tue, 20 Aug 2019 16:46:38 +0200
From:   Julian Wiedmann <jwi@...ux.ibm.com>
To:     David Miller <davem@...emloft.net>
Cc:     <netdev@...r.kernel.org>, <linux-s390@...r.kernel.org>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Stefan Raspl <raspl@...ux.ibm.com>,
        Ursula Braun <ubraun@...ux.ibm.com>,
        Julian Wiedmann <jwi@...ux.ibm.com>
Subject: [PATCH net-next 4/9] s390/qeth: keep cmd alive after IO completion

Current code releases the cmd struct after its initial IO has completed.
Any reply processing is done independently, using a separate qeth_reply
struct.
In preparation for merging the cmd and reply structs together, take an
additional reference on the cmd object so that it stays around all the
way until qeth_send_control_data() returns.

Signed-off-by: Julian Wiedmann <jwi@...ux.ibm.com>
---
 drivers/s390/net/qeth_core_main.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 49e85d2e79c2..3fc14f222dc3 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -1742,6 +1742,9 @@ static int qeth_send_control_data(struct qeth_card *card,
 
 	qeth_enqueue_reply(card, reply);
 
+	/* This pairs with iob->callback, and keeps the iob alive after IO: */
+	qeth_get_cmd(iob);
+
 	QETH_CARD_TEXT(card, 6, "noirqpnd");
 	spin_lock_irq(get_ccwdev_lock(channel->ccwdev));
 	rc = ccw_device_start_timeout(channel->ccwdev, __ccw_from_cmd(iob),
@@ -1752,11 +1755,10 @@ static int qeth_send_control_data(struct qeth_card *card,
 				 CARD_DEVID(card), rc);
 		QETH_CARD_TEXT_(card, 2, " err%d", rc);
 		qeth_dequeue_reply(card, reply);
-		qeth_put_reply(reply);
 		qeth_put_cmd(iob);
 		atomic_set(&channel->irq_pending, 0);
 		wake_up(&card->wait_q);
-		return rc;
+		goto out;
 	}
 
 	timeout = wait_for_completion_interruptible_timeout(&reply->received,
@@ -1777,7 +1779,10 @@ static int qeth_send_control_data(struct qeth_card *card,
 
 	if (!rc)
 		rc = reply->rc;
+
+out:
 	qeth_put_reply(reply);
+	qeth_put_cmd(iob);
 	return rc;
 }
 
-- 
2.17.1