Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 16 Jun 2022 15:34:18 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Oleksij Rempel <o.rempel@pengutronix.de>
Cc:     Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, kernel@pengutronix.de,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH net-next v1 1/1] net: dsa: ar9331: fix potential dead
 lock on mdio access
Message-ID: <YqsxWv79Ge1AFiQx@lunn.ch>
References: <20220616112550.877118-1-o.rempel@pengutronix.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220616112550.877118-1-o.rempel@pengutronix.de>
Precedence: bulk

>  static int ar9331_mdio_read(void *ctx, const void *reg_buf, size_t reg_len,
> @@ -849,6 +849,8 @@ static int ar9331_mdio_read(void *ctx, const void *reg_buf, size_t reg_len,
>  		return 0;
>  	}
>  
> +	mutex_lock_nested(&sbus->mdio_lock, MDIO_MUTEX_NESTED);
> +

Do you know about mdiobus_read_nested() and
mdiobus_write_nested(). The mv88e6xxx driver uses these.

	Andrew