From:   David Mosberger-Tang <davidm@egauge.net>
Subject: [PATCH v2 24/50] wilc1000: protect tx_q_limit with a mutex instead of
 a spinlock
Date:   Thu, 23 Dec 2021 01:14:06 +0000 (UTC)
Message-Id: <20211223011358.4031459-25-davidm@egauge.net>
In-Reply-To: <20211223011358.4031459-1-davidm@egauge.net>
References: <20211223011358.4031459-1-davidm@egauge.net>
MIME-Version: 1.0
To:     Ajay Singh <ajay.kathat@microchip.com>
Cc:     Claudiu Beznea <claudiu.beznea@microchip.com>,
        Kalle Valo <kvalo@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        David Mosberger-Tang <davidm@egauge.net>
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Access to tx_q_limit needs to be serialized among the possibly
multiple writers to the tx queue.  A mutex will do fine for that.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
---
 drivers/net/wireless/microchip/wilc1000/cfg80211.c | 2 ++
 drivers/net/wireless/microchip/wilc1000/netdev.h   | 2 ++
 drivers/net/wireless/microchip/wilc1000/wlan.c     | 5 ++---
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/microchip/wilc1000/cfg80211.c b/drivers/net/wireless/microchip/wilc1000/cfg80211.c
index d352b7dd03283..0fcc064254f1e 100644
--- a/drivers/net/wireless/microchip/wilc1000/cfg80211.c
+++ b/drivers/net/wireless/microchip/wilc1000/cfg80211.c
@@ -1672,6 +1672,7 @@ static void wlan_init_locks(struct wilc *wl)
 
 	spin_lock_init(&wl->txq_spinlock);
 	mutex_init(&wl->txq_add_to_head_cs);
+	mutex_init(&wl->tx_q_limit_lock);
 
 	init_waitqueue_head(&wl->txq_event);
 	init_completion(&wl->cfg_event);
@@ -1688,6 +1689,7 @@ void wlan_deinit_locks(struct wilc *wilc)
 	mutex_destroy(&wilc->txq_add_to_head_cs);
 	mutex_destroy(&wilc->vif_mutex);
 	mutex_destroy(&wilc->deinit_lock);
+	mutex_destroy(&wilc->tx_q_limit_lock);
 	cleanup_srcu_struct(&wilc->srcu);
 }
 
diff --git a/drivers/net/wireless/microchip/wilc1000/netdev.h b/drivers/net/wireless/microchip/wilc1000/netdev.h
index 650b40961cf98..e247f92a409e0 100644
--- a/drivers/net/wireless/microchip/wilc1000/netdev.h
+++ b/drivers/net/wireless/microchip/wilc1000/netdev.h
@@ -257,6 +257,8 @@ struct wilc {
 	atomic_t txq_entries;
 	struct txq_fw_recv_queue_stat fw[NQUEUES];
 
+	/* protect tx_q_limit state */
+	struct mutex tx_q_limit_lock;
 	struct wilc_tx_queue_status tx_q_limit;
 	struct rxq_entry_t rxq_head;
 
diff --git a/drivers/net/wireless/microchip/wilc1000/wlan.c b/drivers/net/wireless/microchip/wilc1000/wlan.c
index f82857cebe35e..9b6605e9df296 100644
--- a/drivers/net/wireless/microchip/wilc1000/wlan.c
+++ b/drivers/net/wireless/microchip/wilc1000/wlan.c
@@ -279,13 +279,12 @@ static void init_q_limits(struct wilc *wl)
 
 static bool is_ac_q_limit(struct wilc *wl, u8 q_num)
 {
-	unsigned long flags;
 	struct wilc_tx_queue_status *q = &wl->tx_q_limit;
 	u8 end_index;
 	u8 q_limit;
 	bool ret = false;
 
-	spin_lock_irqsave(&wl->txq_spinlock, flags);
+	mutex_lock(&wl->tx_q_limit_lock);
 
 	end_index = q->end_index;
 	q->cnt[q->buffer[end_index]] -= factors[q->buffer[end_index]];
@@ -306,7 +305,7 @@ static bool is_ac_q_limit(struct wilc *wl, u8 q_num)
 	if (skb_queue_len(&wl->txq[q_num]) <= q_limit)
 		ret = true;
 
-	spin_unlock_irqrestore(&wl->txq_spinlock, flags);
+	mutex_unlock(&wl->tx_q_limit_lock);
 
 	return ret;
 }
-- 
2.25.1