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 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: s390-qeth-lock-read-device-while-queueing-next-buffer.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Thu Mar 29 08:33:08 CEST 2018

From: Julian Wiedmann jwi@linux.vnet.ibm.com Date: Tue, 20 Mar 2018 07:59:14 +0100 Subject: s390/qeth: lock read device while queueing next buffer

From: Julian Wiedmann jwi@linux.vnet.ibm.com

[ 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 jwi@linux.vnet.ibm.com 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 @@ -517,8 +517,7 @@ 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; @@ -549,6 +548,17 @@ 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; @@ -1174,7 +1184,7 @@ 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-4.4/s390-qeth-when-thread-completes-wake-up-all-waiters.patch queue-4.4/s390-qeth-lock-read-device-while-queueing-next-buffer.patch queue-4.4/net-iucv-free-memory-obtained-by-kzalloc.patch queue-4.4/s390-qeth-on-channel-error-reject-further-cmd-requests.patch queue-4.4/s390-qeth-free-netdevice-when-removing-a-card.patch