netdev - [PATCH v2 net-next 07/14] net: mscc: ocelot: avoid unneeded "lp" variable in LAG join

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Message-Id: <20210116005943.219479-8-olteanv@gmail.com>
Date:   Sat, 16 Jan 2021 02:59:36 +0200
From:   Vladimir Oltean <olteanv@...il.com>
To:     "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     netdev <netdev@...r.kernel.org>,
        Microchip Linux Driver Support <UNGLinuxDriver@...rochip.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Claudiu Manoil <claudiu.manoil@....com>,
        Tobias Waldekranz <tobias@...dekranz.com>,
        Maxim Kochetkov <fido_max@...ox.ru>
Subject: [PATCH v2 net-next 07/14] net: mscc: ocelot: avoid unneeded "lp" variable in LAG join

From: Vladimir Oltean <vladimir.oltean@....com>

The index of the LAG is equal to the logical port ID that all the
physical port members have, which is further equal to the index of the
first physical port that is a member of the LAG.

The code gets a bit carried away with logic like this:

	if (a == b)
		c = a;
	else
		c = b;

which can be simplified, of course, into:

	c = b;

(with a being port, b being lp, c being lag)

This further makes the "lp" variable redundant, since we can use "lag"
everywhere where "lp" (logical port) was used. So instead of a "c = b"
assignment, we can do a complete deletion of b. Only one comment here:

		if (bond_mask) {
			lp = __ffs(bond_mask);
			ocelot->lags[lp] = 0;
		}

lp was clobbered before, because it was used as a temporary variable to
hold the new smallest port ID from the bond. Now that we don't have "lp"
any longer, we'll just avoid the temporary variable and zeroize the
bonding mask directly.

Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
---
Changes in v2:
None.

 drivers/net/ethernet/mscc/ocelot.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index e2744b921a97..ce52bf892f9b 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1273,7 +1273,7 @@ int ocelot_port_lag_join(struct ocelot *ocelot, int port,
 			 struct netdev_lag_upper_info *info)
 {
 	u32 bond_mask = 0;
-	int lag, lp;
+	int lag;
 
 	if (info->tx_type != NETDEV_LAG_TX_TYPE_HASH)
 		return -EOPNOTSUPP;
@@ -1282,22 +1282,18 @@ int ocelot_port_lag_join(struct ocelot *ocelot, int port,
 
 	bond_mask = ocelot_get_bond_mask(ocelot, bond);
 
-	lp = __ffs(bond_mask);
+	lag = __ffs(bond_mask);
 
 	/* If the new port is the lowest one, use it as the logical port from
 	 * now on
 	 */
-	if (port == lp) {
-		lag = port;
+	if (port == lag) {
 		ocelot->lags[port] = bond_mask;
 		bond_mask &= ~BIT(port);
-		if (bond_mask) {
-			lp = __ffs(bond_mask);
-			ocelot->lags[lp] = 0;
-		}
+		if (bond_mask)
+			ocelot->lags[__ffs(bond_mask)] = 0;
 	} else {
-		lag = lp;
-		ocelot->lags[lp] |= BIT(port);
+		ocelot->lags[lag] |= BIT(port);
 	}
 
 	ocelot_setup_lag(ocelot, lag);
-- 
2.25.1