netdev - [PATCH net-next 6/9] s390/qeth: cancel cmds earlier during teardown

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Date:   Wed, 23 Sep 2020 10:36:57 +0200
From:   Julian Wiedmann <jwi@...ux.ibm.com>
To:     David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     netdev <netdev@...r.kernel.org>,
        linux-s390 <linux-s390@...r.kernel.org>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Ursula Braun <ubraun@...ux.ibm.com>,
        Karsten Graul <kgraul@...ux.ibm.com>,
        Julian Wiedmann <jwi@...ux.ibm.com>
Subject: [PATCH net-next 6/9] s390/qeth: cancel cmds earlier during teardown

Originators of cmd IO typically hold the rtnl or conf_mutex to protect
against a concurrent teardown.
Since qeth_set_offline() already holds the conf_mutex, the main reason
why we still care about cancelling pending cmds is so that they release
the rtnl when we need it ourselves.

So move this step a little earlier into the teardown sequence.

Signed-off-by: Julian Wiedmann <jwi@...ux.ibm.com>
---
 drivers/s390/net/qeth_core.h      | 1 -
 drivers/s390/net/qeth_core_main.c | 6 ++++--
 drivers/s390/net/qeth_l2_main.c   | 4 +---
 drivers/s390/net/qeth_l3_main.c   | 1 -
 4 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index f931b764d6a4..711ab5097bd1 100644
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -1067,7 +1067,6 @@ void qeth_put_cmd(struct qeth_cmd_buffer *iob);
 int qeth_schedule_recovery(struct qeth_card *card);
 void qeth_flush_local_addrs(struct qeth_card *card);
 int qeth_poll(struct napi_struct *napi, int budget);
-void qeth_clear_ipacmd_list(struct qeth_card *);
 int qeth_qdio_clear_card(struct qeth_card *, int);
 void qeth_clear_working_pool_list(struct qeth_card *);
 void qeth_drain_output_queues(struct qeth_card *card);
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 7cd0cbf8a4f0..286787845cae 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -965,7 +965,7 @@ static struct qeth_ipa_cmd *qeth_check_ipa_data(struct qeth_card *card,
 	}
 }
 
-void qeth_clear_ipacmd_list(struct qeth_card *card)
+static void qeth_clear_ipacmd_list(struct qeth_card *card)
 {
 	struct qeth_cmd_buffer *iob;
 	unsigned long flags;
@@ -977,7 +977,6 @@ void qeth_clear_ipacmd_list(struct qeth_card *card)
 		qeth_notify_cmd(iob, -ECANCELED);
 	spin_unlock_irqrestore(&card->lock, flags);
 }
-EXPORT_SYMBOL_GPL(qeth_clear_ipacmd_list);
 
 static int qeth_check_idx_response(struct qeth_card *card,
 	unsigned char *buffer)
@@ -5334,6 +5333,9 @@ int qeth_set_offline(struct qeth_card *card, bool resetting)
 		card->info.hwtrap = 1;
 	}
 
+	/* cancel any stalled cmd that might block the rtnl: */
+	qeth_clear_ipacmd_list(card);
+
 	rtnl_lock();
 	card->info.open_when_online = card->dev->flags & IFF_UP;
 	dev_close(card->dev);
diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index e12ac32b8b47..cbd1ab71e785 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -315,10 +315,8 @@ static void qeth_l2_stop_card(struct qeth_card *card)
 	cancel_work_sync(&card->rx_mode_work);
 	qeth_l2_drain_rx_mode_cache(card);
 
-	if (card->state == CARD_STATE_SOFTSETUP) {
-		qeth_clear_ipacmd_list(card);
+	if (card->state == CARD_STATE_SOFTSETUP)
 		card->state = CARD_STATE_DOWN;
-	}
 
 	qeth_qdio_clear_card(card, 0);
 	qeth_drain_output_queues(card);
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index 0815b64c9797..410c35ca8f4a 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -1158,7 +1158,6 @@ static void qeth_l3_stop_card(struct qeth_card *card)
 	if (card->state == CARD_STATE_SOFTSETUP) {
 		card->state = CARD_STATE_DOWN;
 		qeth_l3_clear_ip_htable(card, 1);
-		qeth_clear_ipacmd_list(card);
 	}
 
 	qeth_qdio_clear_card(card, 0);
-- 
2.17.1