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From: "ping.li" <leeonion.muyu@gmail.com>
To: james.morse@arm.com, ben.horgan@arm.com
Cc: linux-kernel@vger.kernel.org, reinette.chatre@intel.com,
	fenghuay@nvidia.com, "ping.li" <ping.li@horizon.auto>
Subject: [PATCH] arm_mpam: Only schedule mpam_enable work after first successful MSC probe
Date: Tue, 18 Aug 2026 21:06:46 +0800	[thread overview]
Message-ID: <20260818130646.663778-1-ping.li@horizon.auto> (raw)

mpam_discovery_cpu_online() sets new_device_probed unconditionally after
processing each reachable MSC. Once an MSC has already been probed
(msc->probed is true), later CPUs sharing it skip
mpam_msc_hw_probe() but still leave err at its default value of 0.
As a result, new_device_probed is still set to true, causing
mpam_enable_work to be scheduled again even though no new hardware was
probed.

Set new_device_probed only when mpam_msc_hw_probe() is called and
succeeds.

Fixes: 8f8d0ac1da78 ("arm_mpam: Add cpuhp callbacks to probe MSC hardware")
Signed-off-by: ping.li <ping.li@horizon.auto>
---
 drivers/resctrl/mpam_devices.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index 2f09f4b78bd3..fefdcf588932 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -1866,13 +1866,15 @@ static int mpam_discovery_cpu_online(unsigned int cpu)
 			continue;
 
 		mutex_lock(&msc->probe_lock);
-		if (!msc->probed)
+		if (!msc->probed) {
 			err = mpam_msc_hw_probe(msc);
+			if (!err)
+				new_device_probed = true;
+		}
 		mutex_unlock(&msc->probe_lock);
 
 		if (err)
 			break;
-		new_device_probed = true;
 	}
 
 	if (new_device_probed && !err)
-- 
2.34.1


             reply	other threads:[~2026-08-18 13:06 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-18 13:06 ping.li [this message]
2026-09-08  2:48 ` [PATCH v2] " ping.li
2026-09-10  9:25   ` Ben Horgan
2026-09-17  9:19     ` Yin Li
2026-09-21 12:39       ` Ben Horgan
2026-09-22  6:16         ` Yin Li
2026-09-15  3:18   ` [PATCH v3] arm_mpam: Use an atomic counter to schedule mpam_enable_once() Ping Li
2026-09-15  9:48     ` Ben Horgan
2026-09-15 11:56     ` [PATCH v4] " Ping Li
2026-09-21 10:49       ` Ben Horgan
2026-09-21 11:49       ` [PATCH v5] " Ping Li
     [not found]         ` <CAKpSQZD2hEuAF9CDD7o9F6v6j-s3sDEwVPtEk9_QLBFjk=nqvA@mail.gmail.com>
2026-10-13  9:40           ` Ben Horgan
2026-10-13 13:03             ` [PATCH v6] " Ping Li
     [not found] <20260818130646.663778-1-ping.li@horizon.auto_quarantine>
2026-09-07 14:02 ` [PATCH] arm_mpam: Only schedule mpam_enable work after first successful MSC probe Ben Horgan

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