FAILED: patch "[PATCH] s390/qeth: fix notification for pending buffers during" failed to apply to 5.4-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.4-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 7eefda7f353ef86ad82a2dc8329e8a3538c08ab6 Mon Sep 17 00:00:00 2001
From: Julian Wiedmann <jwi@linux.ibm.com>
Date: Tue, 9 Mar 2021 17:52:21 +0100
Subject: [PATCH] s390/qeth: fix notification for pending buffers during
 teardown

The cited commit reworked the state machine for pending TX buffers.
In qeth_iqd_tx_complete() it turned PENDING into a transient state, and
uses NEED_QAOB for buffers that get parked while waiting for their QAOB
completion.

But it missed to adjust the check in qeth_tx_complete_buf(). So if
qeth_tx_complete_pending_bufs() is called during teardown to drain
the parked TX buffers, we no longer raise a notification for af_iucv.

Instead of updating the checked state, just move this code into
qeth_tx_complete_pending_bufs() itself. This also gets rid of the
special-case in the common TX completion path.

Fixes: 8908f36d20d8 ("s390/qeth: fix af_iucv notification race")
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 d0a56afec028..a814698387bc 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -1390,9 +1390,6 @@ static void qeth_tx_complete_buf(struct qeth_qdio_out_buffer *buf, bool error,
 	struct qeth_qdio_out_q *queue = buf->q;
 	struct sk_buff *skb;
 
-	if (atomic_read(&buf->state) == QETH_QDIO_BUF_PENDING)
-		qeth_notify_skbs(queue, buf, TX_NOTIFY_GENERALERROR);
-
 	/* Empty buffer? */
 	if (buf->next_element_to_fill == 0)
 		return;
@@ -1465,6 +1462,9 @@ static void qeth_tx_complete_pending_bufs(struct qeth_card *card,
 			QETH_CARD_TEXT(card, 5, "fp");
 			QETH_CARD_TEXT_(card, 5, "%lx", (long) buf);
 
+			if (drain)
+				qeth_notify_skbs(queue, buf,
+						 TX_NOTIFY_GENERALERROR);
 			qeth_tx_complete_buf(buf, drain, 0);
 
 			list_del(&buf->list_entry);