linux-kernel - [PATCH 03/14] ibmvnic: simplify ibmvnic_set_queue

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Message-ID: <20241228184949.31582-4-yury.norov@gmail.com>
Date: Sat, 28 Dec 2024 10:49:35 -0800
From: Yury Norov <yury.norov@...il.com>
To: linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org,
	Haren Myneni <haren@...ux.ibm.com>,
	Rick Lindsley <ricklind@...ux.ibm.com>,
	Nick Child <nnac123@...ux.ibm.com>,
	Thomas Falcon <tlfalcon@...ux.ibm.com>,
	Michael Ellerman <mpe@...erman.id.au>,
	Nicholas Piggin <npiggin@...il.com>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	Naveen N Rao <naveen@...nel.org>,
	Madhavan Srinivasan <maddy@...ux.ibm.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>
Cc: Yury Norov <yury.norov@...il.com>,
	Rasmus Villemoes <linux@...musvillemoes.dk>
Subject: [PATCH 03/14] ibmvnic: simplify ibmvnic_set_queue_affinity()

A loop based on cpumask_next_wrap() opencodes the dedicated macro
for_each_online_cpu_wrap(). Using the macro allows to avoid setting
bits affinity mask more than once when stride >= num_online_cpus.

This also helps to drop cpumask handling code in the caller function.

Signed-off-by: Yury Norov <yury.norov@...il.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index e95ae0d39948..4cfd90fb206b 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -234,11 +234,16 @@ static int ibmvnic_set_queue_affinity(struct ibmvnic_sub_crq_queue *queue,
 		(*stragglers)--;
 	}
 	/* atomic write is safer than writing bit by bit directly */
-	for (i = 0; i < stride; i++) {
-		cpumask_set_cpu(*cpu, mask);
-		*cpu = cpumask_next_wrap(*cpu, cpu_online_mask,
-					 nr_cpu_ids, false);
+	for_each_online_cpu_wrap(i, *cpu) {
+		if (!stride--)
+			break;
+		cpumask_set_cpu(i, mask);
 	}
+
+	/* For the next queue we start from the first unused CPU in this queue */
+	if (i < nr_cpu_ids)
+		*cpu = i + 1;
+
 	/* set queue affinity mask */
 	cpumask_copy(queue->affinity_mask, mask);
 	rc = irq_set_affinity_and_hint(queue->irq, queue->affinity_mask);
@@ -256,7 +261,7 @@ static void ibmvnic_set_affinity(struct ibmvnic_adapter *adapter)
 	int num_rxqs = adapter->num_active_rx_scrqs, i_rxqs = 0;
 	int num_txqs = adapter->num_active_tx_scrqs, i_txqs = 0;
 	int total_queues, stride, stragglers, i;
-	unsigned int num_cpu, cpu;
+	unsigned int num_cpu, cpu = 0;
 	bool is_rx_queue;
 	int rc = 0;
 
@@ -274,8 +279,6 @@ static void ibmvnic_set_affinity(struct ibmvnic_adapter *adapter)
 	stride = max_t(int, num_cpu / total_queues, 1);
 	/* number of leftover cpu's */
 	stragglers = num_cpu >= total_queues ? num_cpu % total_queues : 0;
-	/* next available cpu to assign irq to */
-	cpu = cpumask_next(-1, cpu_online_mask);
 
 	for (i = 0; i < total_queues; i++) {
 		is_rx_queue = false;
-- 
2.43.0