[PATCH v2] net: usb: net1080: add error handling to nc_vendor_write()

From 8c6ffd0b1a5ac33fb6a81cfd4d7d2c54462233bc Mon Sep 17 00:00:00 2001
From: Ashwin Gundarapu <[email protected]>
Date: Mon, 27 Jul 2026 19:34:16 +0530
Subject: [PATCH] net: usb: net1080: add error handling to nc_vendor_write()

The nc_vendor_write() function currently ignores the return value of
usbnet_write_cmd(). This can lead to silent failures when USB
communication fails.

Change nc_vendor_write() and nc_register_write() to return int
instead of void, and propagate the error from usbnet_write_cmd()
back to the caller.

Also fix the callers in net1080_reset() to check the return value
and handle errors appropriately. Remove an unused #if 0 block while
at it.

Signed-off-by: Ashwin Gundarapu <[email protected]>
---
 drivers/net/usb/net1080.c | 55 +++++++++++++--------------------------
 1 file changed, 18 insertions(+), 37 deletions(-)

diff --git a/drivers/net/usb/net1080.c b/drivers/net/usb/net1080.c
index 19f6e1222d93..87848f6e8e01 100644
--- a/drivers/net/usb/net1080.c
+++ b/drivers/net/usb/net1080.c
@@ -113,49 +113,22 @@ nc_register_read(struct usbnet *dev, u8 regnum, u16 *retval_ptr)
 	return nc_vendor_read(dev, REQUEST_REGISTER, regnum, retval_ptr);
 }
 
-static void
+static int
 nc_vendor_write(struct usbnet *dev, u8 req, u8 regnum, u16 value)
 {
-	usbnet_write_cmd(dev, req,
-			 USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
-			 value, regnum, NULL, 0);
+	return usbnet_write_cmd(dev, req,
+				USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+				value, regnum, NULL, 0);
 }
 
-static inline void
+static inline int
 nc_register_write(struct usbnet *dev, u8 regnum, u16 value)
 {
-	nc_vendor_write(dev, REQUEST_REGISTER, regnum, value);
+	return nc_vendor_write(dev, REQUEST_REGISTER, regnum, value);
 }
 
 
-#if 0
-static void nc_dump_registers(struct usbnet *dev)
-{
-	u8	reg;
-	u16	*vp = kmalloc(sizeof (u16));
-
-	if (!vp)
-		return;
 
-	netdev_dbg(dev->net, "registers:\n");
-	for (reg = 0; reg < 0x20; reg++) {
-		int retval;
-
-		// reading some registers is trouble
-		if (reg >= 0x08 && reg <= 0xf)
-			continue;
-		if (reg >= 0x12 && reg <= 0x1e)
-			continue;
-
-		retval = nc_register_read(dev, reg, vp);
-		if (retval < 0)
-			netdev_dbg(dev->net, "reg [0x%x] ==> error %d\n",
-				   reg, retval);
-		else
-			netdev_dbg(dev->net, "reg [0x%x] = 0x%x\n", reg, *vp);
-	}
-	kfree(vp);
-}
 #endif
 
 
@@ -279,8 +252,12 @@ static int net1080_reset(struct usbnet *dev)
 	usbctl = vp;
 	nc_dump_usbctl(dev, usbctl);
 
-	nc_register_write(dev, REG_USBCTL,
-			USBCTL_FLUSH_THIS | USBCTL_FLUSH_OTHER);
+	retval = nc_register_write(dev, REG_USBCTL,
+				   USBCTL_FLUSH_THIS | USBCTL_FLUSH_OTHER);
+	if (retval < 0) {
+		netdev_dbg(dev->net, "can't write USBCTL: %d\n", retval);
+		goto done;
+	}
 
 	if ((retval = nc_register_read(dev, REG_TTL, &vp)) < 0) {
 		netdev_dbg(dev->net, "can't read TTL, %d\n", retval);
@@ -288,8 +265,12 @@ static int net1080_reset(struct usbnet *dev)
 	}
 	ttl = vp;
 
-	nc_register_write(dev, REG_TTL,
-			MK_TTL(NC_READ_TTL_MS, TTL_OTHER(ttl)) );
+	retval = nc_register_write(dev, REG_TTL,
+				   MK_TTL(NC_READ_TTL_MS, TTL_OTHER(ttl)));
+	if (retval < 0) {
+		netdev_dbg(dev->net, "can't write TTL: %d\n", retval);
+		goto done;
+	}
 	netdev_dbg(dev->net, "assigned TTL, %d ms\n", NC_READ_TTL_MS);
 
 	netif_info(dev, link, dev->net, "port %c, peer %sconnected\n",
-- 
2.53.0