Subject: Re: [PATCH net-next v6 05/25] net: dsa: qca8k: handle error with qca8k_read operation

From: "Russell King (Oracle)" <[email-masked]>
Date: Sat, 15 May 2021 00:01:52 +0100

On Fri, May 14, 2021 at 10:59:55PM +0200, Ansuel Smith wrote:
> -static void
> +static int
>  qca8k_fdb_read(struct qca8k_priv *priv, struct qca8k_fdb *fdb)
>  {
> -	u32 reg[4];
> +	u32 reg[4], val;

val is unsigned.

>  	int i;
>  
>  	/* load the ARL table into an array */
> -	for (i = 0; i < 4; i++)
> -		reg[i] = qca8k_read(priv, QCA8K_REG_ATU_DATA0 + (i * 4));
> +	for (i = 0; i < 4; i++) {
> +		val = qca8k_read(priv, QCA8K_REG_ATU_DATA0 + (i * 4));
> +		if (val < 0)
> +			return val;

So this return statement will never be reached.

> @@ -374,6 +386,8 @@ qca8k_fdb_access(struct qca8k_priv *priv, enum qca8k_fdb_cmd cmd, int port)
>  	/* Check for table full violation when adding an entry */
>  	if (cmd == QCA8K_FDB_LOAD) {
>  		reg = qca8k_read(priv, QCA8K_REG_ATU_FUNC);
> +		if (reg < 0)
> +			return reg;

"reg" here is also a u32, and therefore unsigned, so this will have no
effect.

>  		if (reg & QCA8K_ATU_FUNC_FULL)
>  			return -1;
>  	}
> @@ -388,10 +402,10 @@ qca8k_fdb_next(struct qca8k_priv *priv, struct qca8k_fdb *fdb, int port)
>  
>  	qca8k_fdb_write(priv, fdb->vid, fdb->port_mask, fdb->mac, fdb->aging);
>  	ret = qca8k_fdb_access(priv, QCA8K_FDB_NEXT, port);
> -	if (ret >= 0)
> -		qca8k_fdb_read(priv, fdb);
> +	if (ret < 0)
> +		return ret;

This looks fine to me.

>  
> -	return ret;
> +	return qca8k_fdb_read(priv, fdb);
>  }
>  
>  static int
> @@ -449,6 +463,8 @@ qca8k_vlan_access(struct qca8k_priv *priv, enum qca8k_vlan_cmd cmd, u16 vid)
>  	/* Check for table full violation when adding an entry */
>  	if (cmd == QCA8K_VLAN_LOAD) {
>  		reg = qca8k_read(priv, QCA8K_REG_VTU_FUNC1);
> +		if (reg < 0)
> +			return reg;

reg is unsigned... unreachable.

>  		if (reg & QCA8K_VTU_FUNC1_FULL)
>  			return -ENOMEM;
>  	}
> @@ -475,6 +491,8 @@ qca8k_vlan_add(struct qca8k_priv *priv, u8 port, u16 vid, bool untagged)
>  		goto out;
>  
>  	reg = qca8k_read(priv, QCA8K_REG_VTU_FUNC0);
> +	if (reg < 0)
> +		return reg;

reg is unsigned... unreachable.

>  	reg |= QCA8K_VTU_FUNC0_VALID | QCA8K_VTU_FUNC0_IVL_EN;
>  	reg &= ~(QCA8K_VTU_FUNC0_EG_MODE_MASK << QCA8K_VTU_FUNC0_EG_MODE_S(port));
>  	if (untagged)
> @@ -506,6 +524,8 @@ qca8k_vlan_del(struct qca8k_priv *priv, u8 port, u16 vid)
>  		goto out;
>  
>  	reg = qca8k_read(priv, QCA8K_REG_VTU_FUNC0);
> +	if (reg < 0)
> +		return reg;

reg is unsigned... unreachable.

>  	reg &= ~(3 << QCA8K_VTU_FUNC0_EG_MODE_S(port));
>  	reg |= QCA8K_VTU_FUNC0_EG_MODE_NOT <<
>  			QCA8K_VTU_FUNC0_EG_MODE_S(port);
> @@ -621,8 +641,11 @@ qca8k_mdio_read(struct qca8k_priv *priv, int port, u32 regnum)
>  			    QCA8K_MDIO_MASTER_BUSY))
>  		return -ETIMEDOUT;
>  
> -	val = (qca8k_read(priv, QCA8K_MDIO_MASTER_CTRL) &
> -		QCA8K_MDIO_MASTER_DATA_MASK);
> +	val = qca8k_read(priv, QCA8K_MDIO_MASTER_CTRL);
> +	if (val < 0)
> +		return val;

val is unsigned... unreachable.

> +
> +	val &= QCA8K_MDIO_MASTER_DATA_MASK;
>  
>  	return val;
>  }
> @@ -978,6 +1001,8 @@ qca8k_phylink_mac_link_state(struct dsa_switch *ds, int port,
>  	u32 reg;
>  
>  	reg = qca8k_read(priv, QCA8K_REG_PORT_STATUS(port));
> +	if (reg < 0)
> +		return reg;

reg is unsigned... unreachable.

>  
>  	state->link = !!(reg & QCA8K_PORT_STATUS_LINK_UP);
>  	state->an_complete = state->link;
> @@ -1078,18 +1103,26 @@ qca8k_get_ethtool_stats(struct dsa_switch *ds, int port,
>  {
>  	struct qca8k_priv *priv = (struct qca8k_priv *)ds->priv;
>  	const struct qca8k_mib_desc *mib;
> -	u32 reg, i;
> +	u32 reg, i, val;
>  	u64 hi;
>  
>  	for (i = 0; i < ARRAY_SIZE(ar8327_mib); i++) {
>  		mib = &ar8327_mib[i];
>  		reg = QCA8K_PORT_MIB_COUNTER(port) + mib->offset;
>  
> -		data[i] = qca8k_read(priv, reg);
> +		val = qca8k_read(priv, reg);
> +		if (val < 0)
> +			continue;

val is unsigned... unreachable....

> +
>  		if (mib->size == 2) {
>  			hi = qca8k_read(priv, reg + 4);
> -			data[i] |= hi << 32;
> +			if (hi < 0)
> +				continue;

hi is a u64, so this condition is always false.

>  		}
> +
> +		data[i] = val;
> +		if (mib->size == 2)
> +			data[i] |= hi << 32;
>  	}
>  }
>  
> @@ -1107,18 +1140,25 @@ qca8k_set_mac_eee(struct dsa_switch *ds, int port, struct ethtool_eee *eee)
>  {
>  	struct qca8k_priv *priv = (struct qca8k_priv *)ds->priv;
>  	u32 lpi_en = QCA8K_REG_EEE_CTRL_LPI_EN(port);
> +	int ret = 0;

No need to zero-initialise this.

>  	u32 reg;
>  
>  	mutex_lock(&priv->reg_mutex);
>  	reg = qca8k_read(priv, QCA8K_REG_EEE_CTRL);
> +	if (reg < 0) {
> +		ret = reg;
> +		goto exit;
> +	}
> +
>  	if (eee->eee_enabled)
>  		reg |= lpi_en;
>  	else
>  		reg &= ~lpi_en;
>  	qca8k_write(priv, QCA8K_REG_EEE_CTRL, reg);
> -	mutex_unlock(&priv->reg_mutex);
>  
> -	return 0;
> +exit:
> +	mutex_unlock(&priv->reg_mutex);
> +	return ret;
>  }
>  
>  static int
> @@ -1443,6 +1483,9 @@ qca8k_sw_probe(struct mdio_device *mdiodev)
>  
>  	/* read the switches ID register */
>  	id = qca8k_read(priv, QCA8K_REG_MASK_CTRL);
> +	if (id < 0)
> +		return id;

id is unsigned ...

-- 
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