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From: Lorenzo Bianconi <lorenzo@kernel.org>
To: nbd@nbd.name
Cc: lorenzo.bianconi@redhat.com,
	linux-wireless@vger.kernel.org,
	sean.wang@mediatek.com,
	deren.wu@mediatek.com
Subject: [RFT] mt76: sdio: move mcu queue size check inside critical section
Date: Tue, 19 Mar 2024 18:39:24 +0100
Message-ID: <e7b8e26b999918f3b74f951ea87adc5b14bc925b.1710869778.git.lorenzo@kernel.org>
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Even if it is not a real issue at the moment since concurrent access to
mcu message queue is protected by mcu mutex, make the code more robust
and move mcu queue free space check inside queue spinlock critical section.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
compile tested only.
@Deren: can you please run some tests?
---
 drivers/net/wireless/mediatek/mt76/sdio.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/sdio.c b/drivers/net/wireless/mediatek/mt76/sdio.c
index 3e88798df017..6198906946f5 100644
--- a/drivers/net/wireless/mediatek/mt76/sdio.c
+++ b/drivers/net/wireless/mediatek/mt76/sdio.c
@@ -548,10 +548,7 @@ static int
 mt76s_tx_queue_skb_raw(struct mt76_dev *dev, struct mt76_queue *q,
 		       struct sk_buff *skb, u32 tx_info)
 {
-	int ret = -ENOSPC, len = skb->len, pad;
-
-	if (q->queued == q->ndesc)
-		goto error;
+	int ret, len = skb->len, pad;
 
 	pad = round_up(skb->len, 4) - skb->len;
 	ret = mt76_skb_adjust_pad(skb, pad);
@@ -560,6 +557,12 @@ mt76s_tx_queue_skb_raw(struct mt76_dev *dev, struct mt76_queue *q,
 
 	spin_lock_bh(&q->lock);
 
+	if (q->queued == q->ndesc) {
+		ret = -ENOSPC;
+		spin_unlock_bh(&q->lock);
+		goto error;
+	}
+
 	q->entry[q->head].buf_sz = len;
 	q->entry[q->head].skb = skb;
 
-- 
2.44.0