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From: Peter Korsgaard <peter@korsgaard.com>
To: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>,  Eric Dumazet
 <edumazet@google.com>,  Jakub Kicinski <kuba@kernel.org>,  Paolo Abeni
 <pabeni@redhat.com>,  netdev@vger.kernel.org,  linux-usb@vger.kernel.org,
  linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: usb: dm9601: fix wrong return value in
 dm9601_mdio_read
References: <20240225-dm9601_ret_err-v1-1-02c1d959ea59@gmail.com>
Date: Tue, 27 Feb 2024 17:53:22 +0100
In-Reply-To: <20240225-dm9601_ret_err-v1-1-02c1d959ea59@gmail.com> (Javier
	Carrasco's message of "Sun, 25 Feb 2024 00:20:06 +0100")
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>>>>> "Javier" == Javier Carrasco <javier.carrasco.cruz@gmail.com> writes:

 > 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: Peter Korsgaard <peter@korsgaard.com>

-- 
Bye, Peter Korsgaard