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From:   Yang Yingliang <yangyingliang@huawei.com>
To:     <pkshih@realtek.com>, <kvalo@kernel.org>
CC:     <linux-wireless@vger.kernel.org>, <yangyingliang@huawei.com>
Subject: [PATCH v2 2/3] wifi: rtlwifi: rtl8188ee: don't call kfree_skb() under spin_lock_irqsave()
Date:   Wed, 7 Dec 2022 14:28:22 +0800
Message-ID: <20221207062823.3474551-3-yangyingliang@huawei.com>
In-Reply-To: <20221207062823.3474551-1-yangyingliang@huawei.com>
References: <20221207062823.3474551-1-yangyingliang@huawei.com>
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Precedence: bulk

It is not allowed to call kfree_skb() from hardware interrupt
context or with interrupts being disabled. So add all skb to
a free list, then free them after spin_unlock_irqrestore() at
once.

Fixes: 7fe3b3abb5da ("rtlwifi: rtl8188ee: rtl8821ae: Fix a queue locking problem")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
---
 drivers/net/wireless/realtek/rtlwifi/rtl8188ee/hw.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8188ee/hw.c b/drivers/net/wireless/realtek/rtlwifi/rtl8188ee/hw.c
index 58c2ab3d44be..de61c9c0ddec 100644
--- a/drivers/net/wireless/realtek/rtlwifi/rtl8188ee/hw.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rtl8188ee/hw.c
@@ -68,8 +68,10 @@ static void _rtl88ee_return_beacon_queue_skb(struct ieee80211_hw *hw)
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 	struct rtl_pci *rtlpci = rtl_pcidev(rtl_pcipriv(hw));
 	struct rtl8192_tx_ring *ring = &rtlpci->tx_ring[BEACON_QUEUE];
+	struct sk_buff_head free_list;
 	unsigned long flags;
 
+	skb_queue_head_init(&free_list);
 	spin_lock_irqsave(&rtlpriv->locks.irq_th_lock, flags);
 	while (skb_queue_len(&ring->queue)) {
 		struct rtl_tx_desc *entry = &ring->desc[ring->idx];
@@ -79,10 +81,12 @@ static void _rtl88ee_return_beacon_queue_skb(struct ieee80211_hw *hw)
 				 rtlpriv->cfg->ops->get_desc(hw, (u8 *)entry,
 						true, HW_DESC_TXBUFF_ADDR),
 				 skb->len, DMA_TO_DEVICE);
-		kfree_skb(skb);
+		__skb_queue_tail(&free_list, skb);
 		ring->idx = (ring->idx + 1) % ring->entries;
 	}
 	spin_unlock_irqrestore(&rtlpriv->locks.irq_th_lock, flags);
+
+	__skb_queue_purge(&free_list);
 }
 
 static void _rtl88ee_disable_bcn_sub_func(struct ieee80211_hw *hw)
-- 
2.25.1