s390/qeth: schedule TX NAPI on QAOB completion

[ Upstream commit 3e83d467a08e25b27c44c885f511624a71c84f7c ]

When a QAOB notifies us that a pending TX buffer has been delivered, the
actual TX completion processing by qeth_tx_complete_pending_bufs()
is done within the context of a TX NAPI instance. We shouldn't rely on
this instance being scheduled by some other TX event, but just do it
ourselves.

qeth_qdio_handle_aob() is called from qeth_poll(), ie. our main NAPI
instance. To avoid touching the TX queue's NAPI instance
before/after it is (un-)registered, reorder the code in qeth_open()
and qeth_stop() accordingly.

Fixes: 0da9581ddb0f ("qeth: exploit asynchronous delivery of storage blocks")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 03f9617..4d51c4a 100644 (file)
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -470,6 +470,7 @@ static void qeth_qdio_handle_aob(struct qeth_card *card,
        struct qaob *aob;
        struct qeth_qdio_out_buffer *buffer;
        enum iucv_tx_notify notification;
+       struct qeth_qdio_out_q *queue;
        unsigned int i;
 
        aob = (struct qaob *) phys_to_virt(phys_aob_addr);
@@ -511,7 +512,9 @@ static void qeth_qdio_handle_aob(struct qeth_card *card,
                                kmem_cache_free(qeth_core_header_cache, data);
                }
 
+               queue = buffer->q;
                atomic_set(&buffer->state, QETH_QDIO_BUF_EMPTY);
+               napi_schedule(&queue->napi);
                break;
        default:
                WARN_ON_ONCE(1);
@@ -7013,9 +7016,7 @@ int qeth_open(struct net_device *dev)
        card->data.state = CH_STATE_UP;
        netif_tx_start_all_queues(dev);
 
-       napi_enable(&card->napi);
        local_bh_disable();
-       napi_schedule(&card->napi);
        if (IS_IQD(card)) {
                struct qeth_qdio_out_q *queue;
                unsigned int i;
@@ -7027,8 +7028,12 @@ int qeth_open(struct net_device *dev)
                        napi_schedule(&queue->napi);
                }
        }
+
+       napi_enable(&card->napi);
+       napi_schedule(&card->napi);
        /* kick-start the NAPI softirq: */
        local_bh_enable();
+
        return 0;
 }
 EXPORT_SYMBOL_GPL(qeth_open);
@@ -7038,6 +7043,11 @@ int qeth_stop(struct net_device *dev)
        struct qeth_card *card = dev->ml_priv;
 
        QETH_CARD_TEXT(card, 4, "qethstop");
+
+       napi_disable(&card->napi);
+       cancel_delayed_work_sync(&card->buffer_reclaim_work);
+       qdio_stop_irq(CARD_DDEV(card));
+
        if (IS_IQD(card)) {
                struct qeth_qdio_out_q *queue;
                unsigned int i;
@@ -7058,10 +7068,6 @@ int qeth_stop(struct net_device *dev)
                netif_tx_disable(dev);
        }
 
-       napi_disable(&card->napi);
-       cancel_delayed_work_sync(&card->buffer_reclaim_work);
-       qdio_stop_irq(CARD_DDEV(card));
-
        return 0;
 }
 EXPORT_SYMBOL_GPL(qeth_stop);