linux-kernel - [PATCH net-next 4/5] net: dpaa: no need to make sure all CPUs receive a corresponding Tx queue

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Message-Id: <20240710230025.46487-5-vladimir.oltean@nxp.com>
Date: Thu, 11 Jul 2024 02:00:24 +0300
From: Vladimir Oltean <vladimir.oltean@....com>
To: netdev@...r.kernel.org
Cc: "David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Breno Leitao <leitao@...ian.org>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	Madalin Bucur <madalin.bucur@....com>,
	linux-kernel@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org,
	linux-arm-kernel@...ts.infradead.org
Subject: [PATCH net-next 4/5] net: dpaa: no need to make sure all CPUs receive a corresponding Tx queue

dpaa_fq_setup() iterates through the &priv->dpaa_fq_list elements
allocated by dpaa_alloc_all_fqs(). This includes a call to:

	if (!dpaa_fq_alloc(dev, 0, dpaa_max_num_txqs(), list, FQ_TYPE_TX))
		goto fq_alloc_failed;

which gives us dpaa_max_num_txqs() elements of FQ_TYPE_TX type.

The code block which we are deleting runs after an earlier iteration
through &priv->dpaa_fq_list. So at the end of this iteration (for which
there is no early break), egress_cnt will be unconditionally equal to
dpaa_max_num_txqs().

In other words, dpaa_alloc_all_fqs() has already allocated TX queues for
all possible CPUs and the maximal number of traffic classes, and we've
already iterated once through them all.

The while() condition is dead code, remove it.

Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
---
 drivers/net/ethernet/freescale/dpaa/dpaa_eth.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
index e52f4cd95f97..9c0bac58a0da 100644
--- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
+++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
@@ -989,17 +989,6 @@ static int dpaa_fq_setup(struct dpaa_priv *priv,
 		}
 	}
 
-	 /* Make sure all CPUs receive a corresponding Tx queue. */
-	while (egress_cnt < dpaa_max_num_txqs()) {
-		list_for_each_entry(fq, &priv->dpaa_fq_list, list) {
-			if (fq->fq_type != FQ_TYPE_TX)
-				continue;
-			priv->egress_fqs[egress_cnt++] = &fq->fq_base;
-			if (egress_cnt == dpaa_max_num_txqs())
-				break;
-		}
-	}
-
 	kfree(channels);
 
 	return 0;
-- 
2.34.1