Subject: [PATCH net v2] net: dlink: mask rx_coalesce/rx_timeout before writing RxDMAIntCtrl

From: Yeounsu Moon <[email-masked]>
Date: Sat, 3 Jan 2026 18:29:05 +0900

RxDMAIntCtrl encodes rx_coalesce in the low 16 bits
and rx_timeout in the high 16 bits. If either value exceeds
the field width, the current code may truncate the value and/or
corrupt adjacent bits when programming the register.

Mask both values to 16 bits so only the intended fields are written.

Found by inspection.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Tested-on: D-Link DGE-550T Rev-A3
Signed-off-by: Yeounsu Moon <[email-masked]>
---
Changelog:
v2:
- drop unnecessary cast
v1: https://lore.kernel.org/netdev/[email-masked]/
---
 drivers/net/ethernet/dlink/dl2k.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/dlink/dl2k.c b/drivers/net/ethernet/dlink/dl2k.c
index 846d58c769ea..74e0fd08d828 100644
--- a/drivers/net/ethernet/dlink/dl2k.c
+++ b/drivers/net/ethernet/dlink/dl2k.c
@@ -590,7 +590,8 @@ static void rio_hw_init(struct net_device *dev)
 
 	set_multicast (dev);
 	if (np->coalesce) {
-		dw32(RxDMAIntCtrl, np->rx_coalesce | np->rx_timeout << 16);
+		dw32(RxDMAIntCtrl, (np->rx_coalesce & 0x0000ffff) |
+				    (np->rx_timeout & 0x0000ffff) << 16);
 	}
 	/* Set RIO to poll every N*320nsec. */
 	dw8(RxDMAPollPeriod, 0x20);
-- 
2.52.0