From: Julian Wiedmann <jwi@linux.ibm.com>
Date: Mon, 18 Mar 2019 16:40:56 +0100
Subject: s390/qeth: be drop monitor friendly
Git-commit: 104b48592b5441c722dcd95c38ab9300f2d94856
Patch-mainline: v5.1-rc3
References: bsc#1142220 LTC#179335

As part of the TX completion path, qeth_release_skbs() frees the completed
skbs with __skb_queue_purge(). This ends in kfree_skb(), reporting every
completed skb as dropped.
On the other hand when dropping an skb in .ndo_start_xmit, we end up
calling consume_skb()... where we should be using kfree_skb() so that
drop monitors get notified.

Switch the drop/consume logic around, and also don't accumulate dropped
packets in the tx_errors statistics.

Fixes: dc149e3764d8 ("s390/qeth: replace open-coded skb_queue_walk()")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/s390/net/qeth_core_main.c |    5 ++++-
 drivers/s390/net/qeth_l2_main.c   |    3 +--
 drivers/s390/net/qeth_l3_main.c   |    3 +--
 3 files changed, 6 insertions(+), 5 deletions(-)

--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -1198,13 +1198,16 @@ static void qeth_notify_skbs(struct qeth
 
 static void qeth_release_skbs(struct qeth_qdio_out_buffer *buf)
 {
+	struct sk_buff *skb;
+
 	/* release may never happen from within CQ tasklet scope */
 	WARN_ON_ONCE(atomic_read(&buf->state) == QETH_QDIO_BUF_IN_CQ);
 
 	if (atomic_read(&buf->state) == QETH_QDIO_BUF_PENDING)
 		qeth_notify_skbs(buf->q, buf, TX_NOTIFY_GENERALERROR);
 
-	__skb_queue_purge(&buf->skb_list);
+	while ((skb = __skb_dequeue(&buf->skb_list)) != NULL)
+		consume_skb(skb);
 }
 
 static void qeth_clear_output_buffer(struct qeth_qdio_out_q *queue,
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -730,8 +730,7 @@ static netdev_tx_t qeth_l2_hard_start_xm
 
 tx_drop:
 	card->stats.tx_dropped++;
-	card->stats.tx_errors++;
-	dev_kfree_skb_any(skb);
+	kfree_skb(skb);
 	netif_wake_queue(dev);
 	return NETDEV_TX_OK;
 }
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -2229,8 +2229,7 @@ static netdev_tx_t qeth_l3_hard_start_xm
 
 tx_drop:
 	card->stats.tx_dropped++;
-	card->stats.tx_errors++;
-	dev_kfree_skb_any(skb);
+	kfree_skb(skb);
 	netif_wake_queue(dev);
 	return NETDEV_TX_OK;
 }