Patch "s390/qeth: schedule TX NAPI on QAOB completion" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    s390/qeth: schedule TX NAPI on QAOB completion

to the 5.10-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-schedule-tx-napi-on-qaob-completion.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 9c6cd898e1a28572c2dfd4423d1a417c5549e8fc
Author: Julian Wiedmann <jwi@xxxxxxxxxxxxx>
Date:   Tue Mar 9 17:52:20 2021 +0100

    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@xxxxxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 03f96177e58e..4d51c4ace8ea 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);
@@ -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);