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From: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
To: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>
Cc: Sergey Shtylyov <s.shtylyov@omp.ru>,
	Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	=?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>,
	netdev@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Subject: [PATCH] net: ravb: Fix dma_addr_t truncation in error case
Date: Sat, 13 Jan 2024 10:22:21 +0600
Message-Id: <20240113042221.480650-1-nikita.yoush@cogentembedded.com>
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In ravb_start_xmit(), ravb driver uses u32 variable to store result of
dma_map_single() call. Since ravb hardware has 32-bit address fields in
descriptors, this works properly when mapping is successful - it is
platform's job to provide mapping addresses that fit into hardware
limitations.

However, in failure case dma_map_single() returns DMA_MAPPING_ERROR
constant that is 64-bit when dma_addr_t is 64-bit. Storing this constant
in u32 leads to truncation, and further call to dma_mapping_error()
fails to notice the error.

Fix that by storing result of dma_map_single() in a dma_addr_t
variable.

Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
---
 drivers/net/ethernet/renesas/ravb_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 8649b3e90edb..0e3731f50fc2 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -1949,7 +1949,7 @@ static netdev_tx_t ravb_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	struct ravb_tstamp_skb *ts_skb;
 	struct ravb_tx_desc *desc;
 	unsigned long flags;
-	u32 dma_addr;
+	dma_addr_t dma_addr;
 	void *buffer;
 	u32 entry;
 	u32 len;
-- 
2.39.2