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Date:   Wed, 23 Feb 2022 11:48:10 +0100
From:   Andrew Lunn <andrew@lunn.ch>
To:     Heyi Guo <guoheyi@linux.alibaba.com>
Cc:     linux-kernel@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Joel Stanley <joel@jms.id.au>,
        Guangbin Huang <huangguangbin2@huawei.com>,
        Hao Chen <chenhao288@hisilicon.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Dylan Hung <dylan_hung@aspeedtech.com>, netdev@vger.kernel.org
Subject: Re: [PATCH 3/3] drivers/net/ftgmac100: fix DHCP potential failure
 with systemd
Message-ID: <YhYQ6jGQv39rSsDU@lunn.ch>
References: <20220223031436.124858-1-guoheyi@linux.alibaba.com>
 <20220223031436.124858-4-guoheyi@linux.alibaba.com>
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> diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
> index c1deb6e5d26c5..d5356db7539a4 100644
> --- a/drivers/net/ethernet/faraday/ftgmac100.c
> +++ b/drivers/net/ethernet/faraday/ftgmac100.c
> @@ -1402,8 +1402,17 @@ static void ftgmac100_adjust_link(struct net_device *netdev)
>  	/* Disable all interrupts */
>  	iowrite32(0, priv->base + FTGMAC100_OFFSET_IER);
>  
> -	/* Reset the adapter asynchronously */
> -	schedule_work(&priv->reset_task);
> +	/* Release phy lock to allow ftgmac100_reset to aquire it, keeping lock
> +	 * order consistent to prevent dead lock.
> +	 */
> +	if (netdev->phydev)
> +		mutex_unlock(&netdev->phydev->lock);

No need to do this test. The fact that adjust_link is being called
indicates there must be a PHY.

    Andrew