From 6fd2e4466e33ea345174777c409995dea7b30930 Mon Sep 17 00:00:00 2001
From: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Date: Sun, 25 Feb 2024 00:20:06 +0100
Subject: [PATCH] net: usb: dm9601: fix wrong return value in dm9601_mdio_read
Patch-mainline: v6.8-rc7
Git-commit: c68b2c9eba38ec3f60f4894b189090febf4d8d22
References: git-fixes
The MII code does not check the return value of mdio_read (among
others), and therefore no error code should be sent. A previous fix to
the use of an uninitialized variable propagates negative error codes,
that might lead to wrong operations by the MII library.
An example of such issues is the use of mii_nway_restart by the dm9601
driver. The mii_nway_restart function does not check the value returned
by mdio_read, which in this case might be a negative number which could
contain the exact bit the function checks (BMCR_ANENABLE = 0x1000).
Return zero in case of error, as it is common practice in users of
mdio_read to avoid wrong uses of the return value.
Fixes: 8f8abb863fa5 ("net: usb: dm9601: fix uninitialized variable use in dm9601_mdio_read")
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Peter Korsgaard <peter@korsgaard.com>
Link: https://lore.kernel.org/r/20240225-dm9601_ret_err-v1-1-02c1d959ea59@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
drivers/net/usb/dm9601.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/usb/dm9601.c b/drivers/net/usb/dm9601.c
index 5aad26600b03..9b7db5fd9e08 100644
--- a/drivers/net/usb/dm9601.c
+++ b/drivers/net/usb/dm9601.c
@@ -231,7 +231,7 @@ static int dm9601_mdio_read(struct net_device *netdev, int phy_id, int loc)
err = dm_read_shared_word(dev, 1, loc, &res);
if (err < 0) {
netdev_err(dev->net, "MDIO read error: %d\n", err);
- return err;
+ return 0;
}
netdev_dbg(dev->net,
--
2.16.4