[PATCH] net: stmmac: use dma_addr_t for DMA addresses

Alex Elder elder at riscstar.com
Tue Aug 11 12:27:02 PDT 2026


In jumbo_frm() (implemented in both "chain_mode.c" and "ring_mode.c"),
an unsigned integer local variable is used to hold the value returned
by dma_map_single().  On systems where a dma_addr_t is 64 bits, the
subsequent dma_mapping_error() check of the returned value operates
only on the low 32 bits (whose high bit won't be sign-extended).  In
this case, dma_mapping_error() would return 0 (no error) even if there
were one.

Fix this in both spots by using a dma_addr_t for the local variable.

Reported-by: Sashiko <sashiko-bot at kernel.org>
Link: https://lore.kernel.org/linux-devicetree/20260606010122.21A211F00899@smtp.kernel.org/
Signed-off-by: Alex Elder <elder at riscstar.com>
---
 drivers/net/ethernet/stmicro/stmmac/chain_mode.c | 3 ++-
 drivers/net/ethernet/stmicro/stmmac/ring_mode.c  | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
index fc04a23342cfc..ec25193d287bb 100644
--- a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
@@ -20,9 +20,10 @@ static int jumbo_frm(struct stmmac_tx_queue *tx_q, struct sk_buff *skb,
 	unsigned int nopaged_len = skb_headlen(skb);
 	struct stmmac_priv *priv = tx_q->priv_data;
 	unsigned int entry = tx_q->cur_tx;
-	unsigned int bmax, buf_len, des2;
+	unsigned int bmax, buf_len;
 	unsigned int i = 1, len;
 	struct dma_desc *desc;
+	dma_addr_t des2;
 
 	desc = tx_q->dma_tx + entry;
 
diff --git a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
index 78fc6aa5bbe95..664d8cfb58cdc 100644
--- a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
@@ -20,8 +20,9 @@ static int jumbo_frm(struct stmmac_tx_queue *tx_q, struct sk_buff *skb,
 	unsigned int nopaged_len = skb_headlen(skb);
 	struct stmmac_priv *priv = tx_q->priv_data;
 	unsigned int entry = tx_q->cur_tx;
-	unsigned int bmax, len, des2;
+	unsigned int bmax, len;
 	struct dma_desc *desc;
+	dma_addr_t des2;
 
 	if (priv->extend_desc)
 		desc = (struct dma_desc *)(tx_q->dma_etx + entry);

base-commit: 31397cf1819210bd63fa3d2c7d8c24f7c8667d99
-- 
2.53.0




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