linux-kernel - [PATCH v2] platform/x86: ISST: Fix optimization with use of numa

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Date:   Tue, 10 Aug 2021 20:36:33 -0700
From:   Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To:     hdegoede@...hat.com, mgross@...ux.intel.com
Cc:     platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
        sfr@...b.auug.org.au,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Subject: [PATCH v2] platform/x86: ISST: Fix optimization with use of numa

When numa is used to map CPU to PCI device, the optimized path to read
from cached data is not working and still calls _isst_if_get_pci_dev().

The reason is that when caching the mapping, numa information is not
available as it is read later. So move the assignment of
isst_cpu_info[cpu].numa_node before calling _isst_if_get_pci_dev().

Fixes: aa2ddd242572 ("platform/x86: ISST: Use numa node id for cpu pci dev mapping")
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
---
v2:
Fixed "Fixes tag" as suggested by Stephen Rothwell

Update:
	The fixes tag was wrong
This patch can wait for next merge window as these systems are not
shipped.

 drivers/platform/x86/intel_speed_select_if/isst_if_common.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/intel_speed_select_if/isst_if_common.c b/drivers/platform/x86/intel_speed_select_if/isst_if_common.c
index 6f0cc679c8e5..8a4d52a9028d 100644
--- a/drivers/platform/x86/intel_speed_select_if/isst_if_common.c
+++ b/drivers/platform/x86/intel_speed_select_if/isst_if_common.c
@@ -379,6 +379,8 @@ static int isst_if_cpu_online(unsigned int cpu)
 	u64 data;
 	int ret;
 
+	isst_cpu_info[cpu].numa_node = cpu_to_node(cpu);
+
 	ret = rdmsrl_safe(MSR_CPU_BUS_NUMBER, &data);
 	if (ret) {
 		/* This is not a fatal error on MSR mailbox only I/F */
@@ -397,7 +399,6 @@ static int isst_if_cpu_online(unsigned int cpu)
 		return ret;
 	}
 	isst_cpu_info[cpu].punit_cpu_id = data;
-	isst_cpu_info[cpu].numa_node = cpu_to_node(cpu);
 
 	isst_restore_msr_local(cpu);
 
-- 
2.31.1