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From:   Felix Fietkau <nbd@nbd.name>
To:     linux-wireless@vger.kernel.org
Subject: [PATCH 2/4] mt76: mt76x02: remove irqsave/restore in locking for tx status fifo
Date:   Mon, 29 Apr 2019 19:17:10 +0200
Message-Id: <20190429171712.52983-2-nbd@nbd.name>
In-Reply-To: <20190429171712.52983-1-nbd@nbd.name>
References: <20190429171712.52983-1-nbd@nbd.name>
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

Use a separate lock and spin_trylock to avoid disabling interrupts.
Should improve performance and latency

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 drivers/net/wireless/mediatek/mt76/mt76x02.h      | 1 +
 drivers/net/wireless/mediatek/mt76/mt76x02_mac.c  | 7 ++++---
 drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c | 1 +
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02.h b/drivers/net/wireless/mediatek/mt76/mt76x02.h
index cd37f44580ba..9f103c2506db 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02.h
@@ -86,6 +86,7 @@ struct mt76x02_dev {
 
 	u8 txdone_seq;
 	DECLARE_KFIFO_PTR(txstatus_fifo, struct mt76x02_tx_status);
+	spinlock_t txstatus_fifo_lock;
 
 	struct sk_buff *rx_head;
 
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c b/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c
index 28851060aa0f..c1f041e1a279 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c
@@ -739,7 +739,6 @@ int mt76x02_mac_process_rx(struct mt76x02_dev *dev, struct sk_buff *skb,
 void mt76x02_mac_poll_tx_status(struct mt76x02_dev *dev, bool irq)
 {
 	struct mt76x02_tx_status stat = {};
-	unsigned long flags;
 	u8 update = 1;
 	bool ret;
 
@@ -749,9 +748,11 @@ void mt76x02_mac_poll_tx_status(struct mt76x02_dev *dev, bool irq)
 	trace_mac_txstat_poll(dev);
 
 	while (!irq || !kfifo_is_full(&dev->txstatus_fifo)) {
-		spin_lock_irqsave(&dev->mt76.mmio.irq_lock, flags);
+		if (!spin_trylock(&dev->txstatus_fifo_lock))
+			break;
+
 		ret = mt76x02_mac_load_tx_status(dev, &stat);
-		spin_unlock_irqrestore(&dev->mt76.mmio.irq_lock, flags);
+		spin_unlock(&dev->txstatus_fifo_lock);
 
 		if (!ret)
 			break;
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c b/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
index 87e14af7a93b..5bc1b901f897 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
@@ -201,6 +201,7 @@ int mt76x02_dma_init(struct mt76x02_dev *dev)
 	tasklet_init(&dev->pre_tbtt_tasklet, mt76x02_pre_tbtt_tasklet,
 		     (unsigned long)dev);
 
+	spin_lock_init(&dev->txstatus_fifo_lock);
 	kfifo_init(&dev->txstatus_fifo, status_fifo, fifo_size);
 
 	mt76_dma_attach(&dev->mt76);
-- 
2.17.0