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From:   gregkh@linuxfoundation.org
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Biao Huang <biao.huang@mediatek.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.11 055/306] net: ethernet: mtk-star-emac: fix wrong unmap in RX handling
Date:   Mon, 15 Mar 2021 14:51:58 +0100
Message-Id: <20210315135509.511797491@linuxfoundation.org>
In-Reply-To: <20210315135507.611436477@linuxfoundation.org>
References: <20210315135507.611436477@linuxfoundation.org>
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

From: Biao Huang <biao.huang@mediatek.com>

commit 95b39f07a17faef3a9b225248ba449b976e529c8 upstream.

mtk_star_dma_unmap_rx() should unmap the dma_addr of old skb rather than
that of new skb.
Assign new_dma_addr to desc_data.dma_addr after all handling of old skb
ends to avoid unexpected receive side error.

Fixes: f96e9641e92b ("net: ethernet: mtk-star-emac: fix error path in RX handling")
Signed-off-by: Biao Huang <biao.huang@mediatek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/mediatek/mtk_star_emac.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/mediatek/mtk_star_emac.c
+++ b/drivers/net/ethernet/mediatek/mtk_star_emac.c
@@ -1225,8 +1225,6 @@ static int mtk_star_receive_packet(struc
 		goto push_new_skb;
 	}
 
-	desc_data.dma_addr = new_dma_addr;
-
 	/* We can't fail anymore at this point: it's safe to unmap the skb. */
 	mtk_star_dma_unmap_rx(priv, &desc_data);
 
@@ -1236,6 +1234,9 @@ static int mtk_star_receive_packet(struc
 	desc_data.skb->dev = ndev;
 	netif_receive_skb(desc_data.skb);
 
+	/* update dma_addr for new skb */
+	desc_data.dma_addr = new_dma_addr;
+
 push_new_skb:
 	desc_data.len = skb_tailroom(new_skb);
 	desc_data.skb = new_skb;