From: Deren Wu <deren.wu@mediatek.com>
Date: Sun, 15 Jan 2023 04:44:57 +0000 (+0800)
Subject: wifi: mt76: add memory barrier to SDIO queue kick
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5f54237ad798f41cb6a503271aa9ca47188cfb9b;p=linux.git

wifi: mt76: add memory barrier to SDIO queue kick

Ensure the entry has been fully updated before SDIO bus worker access
it. This patch would fix potential memory risk in both mt7663s and
mt7921s.

Fixes: 764dee47e2c1 ("mt76: sdio: move common code in mt76_sdio module")
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

diff --git a/drivers/net/wireless/mediatek/mt76/sdio.c b/drivers/net/wireless/mediatek/mt76/sdio.c
index 228bc7d45011c..419723118ded8 100644
--- a/drivers/net/wireless/mediatek/mt76/sdio.c
+++ b/drivers/net/wireless/mediatek/mt76/sdio.c
@@ -562,6 +562,10 @@ mt76s_tx_queue_skb_raw(struct mt76_dev *dev, struct mt76_queue *q,
 
 	q->entry[q->head].buf_sz = len;
 	q->entry[q->head].skb = skb;
+
+	/* ensure the entry fully updated before bus access */
+	smp_wmb();
+
 	q->head = (q->head + 1) % q->ndesc;
 	q->queued++;