linux-kernel - [PATCH v5 14/19] arch_topology: Avoid parsing through all the CPUs once a outlier CPU is found

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Message-Id: <20220627165047.336669-15-sudeep.holla@arm.com>
Date:   Mon, 27 Jun 2022 17:50:42 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     linux-kernel@...r.kernel.org
Cc:     Sudeep Holla <sudeep.holla@....com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Atish Patra <atishp@...shpatra.org>,
        Atish Patra <atishp@...osinc.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Qing Wang <wangqing@...o.com>,
        Rob Herring <robh+dt@...nel.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Ionela Voinescu <ionela.voinescu@....com>,
        Pierre Gondois <pierre.gondois@....com>,
        linux-arm-kernel@...ts.infradead.org,
        linux-riscv@...ts.infradead.org, Gavin Shan <gshan@...hat.com>
Subject: [PATCH v5 14/19] arch_topology: Avoid parsing through all the CPUs once a outlier CPU is found

There is no point in looping through all the CPU's physical package
identifier to check if it is valid or not once a CPU which is outside
the topology(i.e. outlier CPU) is found.

Let us just break out of the loop early in such case.

Link: https://lore.kernel.org/r/20220621192034.3332546-15-sudeep.holla@arm.com
Tested-by: Ionela Voinescu <ionela.voinescu@....com>
Reviewed-by: Gavin Shan <gshan@...hat.com>
Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 drivers/base/arch_topology.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index ef90d9c00d9e..7a569aefe313 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -642,8 +642,10 @@ static int __init parse_dt_topology(void)
 	 * only mark cores described in the DT as possible.
 	 */
 	for_each_possible_cpu(cpu)
-		if (cpu_topology[cpu].package_id < 0)
+		if (cpu_topology[cpu].package_id < 0) {
 			ret = -EINVAL;
+			break;
+		}
 
 out_map:
 	of_node_put(map);
-- 
2.36.1