The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 3e83d467a08e25b27c44c885f511624a71c84f7c Mon Sep 17 00:00:00 2001
From: Julian Wiedmann jwi@linux.ibm.com Date: Tue, 9 Mar 2021 17:52:20 +0100 Subject: [PATCH] s390/qeth: schedule TX NAPI on QAOB completion
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
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index 3763cd6d14f8..d0a56afec028 100644 --- 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); @@ -512,7 +513,9 @@ static void qeth_qdio_handle_aob(struct qeth_card *card, buffer->is_header[i] = 0; }
+ queue = buffer->q; atomic_set(&buffer->state, QETH_QDIO_BUF_EMPTY); + napi_schedule(&queue->napi); break; default: WARN_ON_ONCE(1); @@ -7235,9 +7238,7 @@ 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; @@ -7249,8 +7250,12 @@ 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); @@ -7260,6 +7265,11 @@ 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; @@ -7280,10 +7290,6 @@ 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);