[PATCH net 3/4] s390/qeth: lock read device while queueing next buffer

[Julian Wiedmann]

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 <j...@linux.vnet.ibm.com>
---
 drivers/s390/net/qeth_core_main.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/s390/net/qeth_core_main.c 
b/drivers/s390/net/qeth_core_main.c
index 42ee8806fa53..2a9afaf8f264 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -527,8 +527,7 @@ static inline int qeth_is_cq(struct qeth_card *card, 
unsigned int queue)
            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;
@@ -559,6 +558,17 @@ static int qeth_issue_next_read(struct qeth_card *card)
        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;
@@ -1182,7 +1192,7 @@ static void qeth_irq(struct ccw_device *cdev, unsigned 
long intparm,
                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;
-- 
2.13.5