Patch "s390/qeth: lock read device while queueing next buffer" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

    s390/qeth: lock read device while queueing next buffer

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     s390-qeth-lock-read-device-while-queueing-next-buffer.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let [off-list ref] know about it.

From foo@baz Wed Mar 28 18:38:30 CEST 2018

From: Julian Wiedmann <redacted>
Date: Tue, 20 Mar 2018 07:59:14 +0100
Subject: s390/qeth: lock read device while queueing next buffer

From: Julian Wiedmann <redacted>


[ Upstream commit 17bf8c9b3d499d5168537c98b61eb7a1fcbca6c2 ]

For calling ccw_device_start(), issue_next_read() needs to hold the
device's ccwlock.
This is satisfied for the IRQ handler path (where qeth_irq() gets called
under the ccwlock), but we need explicit locking for the initial call by
the MPC initialization.

Signed-off-by: Julian Wiedmann <redacted>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/s390/net/qeth_core_main.c |   16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c

@@ -526,8 +526,7 @@ static inline int qeth_is_cq(struct qeth
 	    queue == card->qdio.no_in_queues - 1;
 }
 
-
-static int qeth_issue_next_read(struct qeth_card *card)
+static int __qeth_issue_next_read(struct qeth_card *card)
 {
 	int rc;
 	struct qeth_cmd_buffer *iob;

@@ -558,6 +557,17 @@ static int qeth_issue_next_read(struct q
 	return rc;
 }
 
+static int qeth_issue_next_read(struct qeth_card *card)
+{
+	int ret;
+
+	spin_lock_irq(get_ccwdev_lock(CARD_RDEV(card)));
+	ret = __qeth_issue_next_read(card);
+	spin_unlock_irq(get_ccwdev_lock(CARD_RDEV(card)));
+
+	return ret;
+}
+
 static struct qeth_reply *qeth_alloc_reply(struct qeth_card *card)
 {
 	struct qeth_reply *reply;

@@ -1183,7 +1193,7 @@ static void qeth_irq(struct ccw_device *
 		return;
 	if (channel == &card->read &&
 	    channel->state == CH_STATE_UP)
-		qeth_issue_next_read(card);
+		__qeth_issue_next_read(card);
 
 	iob = channel->iob;
 	index = channel->buf_no;

Patches currently in stable-queue which might be from jwi@linux.vnet.ibm.com are

queue-4.14/s390-qeth-when-thread-completes-wake-up-all-waiters.patch
queue-4.14/s390-qeth-lock-read-device-while-queueing-next-buffer.patch
queue-4.14/net-iucv-free-memory-obtained-by-kzalloc.patch
queue-4.14/s390-qeth-on-channel-error-reject-further-cmd-requests.patch
queue-4.14/s390-qeth-free-netdevice-when-removing-a-card.patch